International
Tables for
Crystallography
Volume C
Mathematical, physical and chemical tables
Edited by E. Prince

International Tables for Crystallography (2006). Vol. C, ch. 9.6, pp. 812-896
https://doi.org/10.1107/97809553602060000622

Chapter 9.6. Typical interatomic distances: organometallic compounds and coordination complexes of the d- and f-block metals

A. G. Orpen,a L. Brammer,b F. H. Allen,c D. G. Watsonc and R. Taylorc

aSchool of Chemistry, University of Bristol, Bristol BS8 1TS, England,bDepartment of Chemistry, University of Missouri–St Louis, 8001 Natural Bridge Road, St Louis, MO 63121-4499, USA, and cCambridge Crystallographic Data Centre, 12 Union Road, Cambridge CB2 1EZ, England

Statistics, including averages, for lengths of metal–ligand bonds are reported, together with some intraligand distances, for complexes of the d- and f-block metals. Mean values are presented for 325 different bond types involving metal atoms bonded to H, B, C, N, O, F, Si, P, S, Cl, As, Se, Br, Te or I atoms of the ligands.

9.6.1. Introduction

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The determination of molecular geometry is of vital importance to our understanding of chemical structure and bonding. The majority of experimental data have come from X-ray and neutron diffraction, microwave spectroscopy, and electron diffraction. Over the years, compilations of results from these techniques have appeared sporadically. The first major compilation was Chemical Society Special Publication No. 11: Tables of Interatomic Distances and Configuration in Molecules and Ions (Sutton, 1958[link]). This volume summarized results obtained by diffraction and spectroscopic methods prior to 1956; a supplementary volume (Sutton, 1965[link]) extended this coverage to 1959. Summary tables of bond lengths between carbon and other elements were also published in Volume III of International Tables for X-ray Crystallography (Kennard, 1962[link]). Some years later, the Cambridge Crystallographic Data Centre (Allen, Bellard, Brice, Cartwright, Doubleday, Higgs, Hummelink, Hummelink-Peters, Kennard, Motherwell, Rodgers & Watson, 1979[link]) produced an atlas-style compendium of all organic, organometallic and metal-complex crystal structures published in the period 1960–1965 (Kennard, Watson, Allen, Isaacs, Motherwell, Pettersen & Town, 1972[link]). More recently, a survey of geometries determined by spectroscopic methods (Harmony, Laurie, Kuczkowski, Schwendemann, Ramsay, Lovas, Lafferty & Maki, 1979[link]) has extended coverage in this area to mid-1977. A notable compendium of structural data, without geometric information, was given in Comprehensive Organometallic Chemistry (Bruce, 1981[link]), covering all complexes with metal–carbon bonds. The BIDICS (Brown, Brown & Hawthorne, 1982[link]) series, which finished in 1981, provided for some years a full coverage of metal complexes giving both bibliographic and geometric information. There have also been valuable annual summaries, without geometric information, on the structures of organometallic compounds determined by diffraction methods (Russell, 1988[link]).

The production of further comprehensive compendia of X-ray and neutron diffraction results has been precluded by the steep rise in the number of published crystal structures, as illustrated by Fig. 9.6.1.1[link]. Print compilations have been effectively superseded by computerized databases. In particular, the Cambridge Structural Database now contains bibliographic, chemical, and numerical results for some 86 000 organo-carbon crystal structures. This machine-readable file fulfils the function of a comprehensive structure-by-structure compendium of molecular geometries. However, the amount of data now held in the CSD is so large that there is also a need for concise, printed tabulations of average molecular dimensions.

[Figure 9.6.1.1]

Figure 9.6.1.1 | top | pdf |

Growth of the Cambridge Structural Database as number of entries (Nent) added annually. The structures containing d- or f-block metals are indicated by shading.

The only tables of average geometry in general use are those contained in the Chemical Society Special Publications of 1958 and 1965 (Sutton, 1958[link], 1965[link]), which list mean bond lengths for a variety of atom pairs and functional groups. Since these early tables were based on data obtained before 1960, we have used the CSD to prepare a new table of average bond lengths in organic compounds (see Chapter 9.5[link] ) and in metal complexes. The table given here (Table 9.6.3.3[link]) specifically lists average lengths for metal–ligand distances, together with intra-ligand distances, involving bonds between the d- and f-block metals (Sc–Zn, Y–Cd, La–Hg, Ce–Lu, Th–U) and atoms H, B, C, N, O, F, Si, P, S, Cl, As, Se, Br, Te, and I of ligands. Mean values are presented for 324 different bond types involving such metal–ligand bonds.

9.6.2. Methodology

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9.6.2.1. Selection of crystallographic data

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All results given in Table 9.6.3.3[link] are based on X-ray and neutron diffraction results retrieved from the September 1985 version of the CSD. Neutron diffraction data only were used to derive mean bond lengths involving hydrogen atoms. This version of the CSD contained results for 49 854 single-crystal diffraction studies of organo-carbon compounds; 9802 of these satisfied the acceptance criteria listed below and were used in the averaging procedures:

  • (i) Structure contains a d- or f-block metal.

  • (ii) Atomic coordinates for the structure have been published and are available in the CSD.

  • (iii) Structure was determined from diffractometer data.

  • (iv) Structure does not contain unresolved numeric data errors from the original publication (such errors are usually typographical and are normally resolved by consultation with the authors).

  • (v) Only structures of higher precision were included on the basis that either (a) the crystallographic R factor was ≤ 0.07 and the reported mean estimated standard deviation (e.s.d.) of the C—C bond lengths was ≤ 0.030 Å (corresponds to AS flag = 1, 2 or 3 in the CSD), or (b) the crystallographic R factor ≤ 0.05 and the mean e.s.d. for C—C bonds was not available in the database (AS = 0 in the CSD).

  • (vi) Where the structure of a given compound had been determined more than once within the limits of (i)–(v), then only the most precise determination was used.

The structures used in Table 9.6.3.3[link] do not include compounds whose structure precludes them from the CSD (i.e. not containing `organic' carbon). In practice, structures including at least one C—H bond are taken to contain `organic' carbon. Thus, the entry for Cr—CO distances has a contribution from [NEt4][Cr(μ-H)(CO)10] but not from K[Cr(μ-H)(CO)10] or [Cr(CO)6].

9.6.2.2. Program system

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All calculations were performed on a University of Bristol VAX 11/750 computer. Programs BIBSER, CONNSER, RETRIEVE (Allen et al., 1979[link]) and GEOSTAT (Murray-Rust & Raftery, 1985a[link],b[link]), as locally modified, were used. A stand-alone program was written to implement the selection criteria, whilst a new program (STATS) was used for statistical calculations described below. It was also necessary to modify CONNSER to improve the precision with which it locates chemical substructures. In particular, the program was altered to permit the location of atoms with specified coordination numbers. This was essential in the case of carbon so that atoms with coordination numbers 2, 3, and 4 (equivalent to formal hybridization state sp1, sp2, sp3) could be distinguished easily and reliably. Considerable care was taken to ensure that the correct molecular fragment was located by GEOSTAT in the generation of geometrical tabulations. Searches were conducted for all metals together and statistics for individual metal elements and subdivision of the entry for a given metal carried out subsequently. An important modification to GEOSTAT allowed for calculation of metal-atom coordination number with due allowance for multihapto ligands and μ2 ligands. Thus, η5-C5H5, η6-C6H6, and other η5 and η6 ligands were assigned to occupy 3 coordination sites, η3 and η4 ligands such as allyls and dienes to occupy 2 coordination sites, and η2 ligands such as alkenes 1 site, and so on. The approach taken in dealing with (μ2) bridging ligands was that when a metal–metal bond is bridged by one atom of a ligand [e.g. as in Cl, CO, OMe etc. as in (a), (b) below] then only the non-metal atom is counted as occupying a coordination site. For the relatively rare case of bridging polyhapto ligands (in which the bridging atoms are linked by direct bonds), the assignment follows logically, thus, μ222-alkyne, see (c) below, occupies one site on each metal. Bridging ligands that do not have one atom bonded to both metals [e.g. acetate in (d) below] contribute to metal coordination numbers as do terminal ligands. In examples (a)–(d) below, the metal atoms therefore have coordination numbers as follows: (a), Rh 4; (b), Fe 6; (c), Co 4; (d), Rh 6. For cases where coordination number is very difficult to assign, notably where a metal atom is bonded to more than one other metal atom as in metal cluster complexes, no assignment was attempted. [Scheme cbch9.6scheme1]

The non-location of hydrogen atoms presents major difficulties, both in the determination of coordination numbers for metal atoms, and for correct identification of ligands (e.g. to distinguish methoxide from methanol). Care was therefore taken to exclude cases where any ambiguity existed [e.g. no data taken for M—(OCH3) and M—O(H)CH3 distances when both are present in a structure in which hydrogen-atom positions were not reported].

9.6.2.3. Classification of bonds

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The classification of metal–ligand bonds in Table 9.6.3.3[link] is based on the ligating contacting atom. Thus, all metal–boron distances appear in sections 2.1–2.3 of Table 9.6.3.3[link], all metal–carbon distances in sections 3.1–3.22, and so on. Where intra-ligand interatomic distances (e.g. P—C distances in tertiary phosphines) are given in Table 9.6.3.3[link], they are averaged over all metals and precede the individual metal–ligand interatomic distances for that ligand.

Table 9.6.3.3[link] is designated: (i) to appear logical, useful, and reasonably self-explanatory to chemists, crystallographers, and others who may use it; (ii) to permit a meaningful average value to be cited for each bond length. With reference to (ii), it was considered that a sample of bond lengths could be averaged meaningfully if: (a) the sample was unimodally distributed; (b) the sample standard deviation (σ) was reasonably small, ideally less than ca 0.04 Å; (c) there were no conspicuous outlying observations – those that occurred at > 4σ from the mean were automatically eliminated from the sample by STATS, other outliers were inspected carefully; (d) there were no compelling chemical reasons for further subdivision of the sample. It should be noted that Table 9.6.3.3[link] is not intended to be complete in covering all possible ligands. The purpose of the table is to provide information on the interatomic distances for ligands of the greatest chemical importance, notably for those that are simple and/or common.

9.6.2.4. Statistics

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Where there are less than four independent observations of a given bond length, then each individual observation is given explicitly in Table 9.6.3.3[link]. In all other cases, the following statistics were generated by the program STATS.

  • (i) The unweighted sample mean, d, where [d=\textstyle\sum\limits^n_{i=1}d_i/n]and [d_i] is the ith observation of the bond length in a total sample of n observations. Recent work (Taylor & Kennard, 1983[link], 1985[link], 1986[link]) has shown that the unweighted mean is an acceptable (even preferable) alternative to the weighted mean, where the ith observation is assigned a weight equal to 1/var(di). This is especially true where structures have been pre-screened on the basis of precision.

  • (ii) The sample median, m. This has the property that half of the observations in the sample exceed m, and half fall short of it.

  • (iii) The sample standard deviation, σ, where [\sigma=\left[\textstyle\sum\limits^n_{i=1}(d_i-d)^2/(n-1)\right]^{1/2}.]

  • (iv) The lower quartile for the sample, [q_l]. This has the property that 25% of the observations are less than [q_l] and 75% exceed it.

  • (v) The upper quartile for the sample, [q_u]. This has the property that 25% of the observations exceed [q_u] and 75% fall short of it.

  • (vi) The number (n) of observations in the sample.

The statistics given in Table 9.6.3.3[link] correspond to distributions for which the automatic 4σ cut-off (see above) had been applied, and any manual removal of additional outliers (an infrequent operation) had been performed. In practice, a very small percentage of observations were excluded by these methods. The major effect of removing outliers is to improve the sample standard deviation, as shown in Fig. 9.6.2.1(b)[link] in which four (out of 366) observations are deleted.

[Figure 9.6.2.1]

Figure 9.6.2.1 | top | pdf |

Effects of outlier removal and subdivision based on coordination number and oxidation state. Cu—Cl: (a) all data; (b) all data without outliers [> 4σ (sample) from mean]; (c) all data for which Cu is 4-coordinate, CuII.[\matrix{&d &m &\sigma &q_l &q_u &N \cr (a) &2.282 &2.255 &0.105 &2.233 &2.296 &366 \cr (b) &2.276 &2.254 &0.092 &2.232 &2.292 &362 \cr (c) &2.248 &2.246 &0.032 &2.233 &2.263 &153\cr}]

The statistics chosen for tabulation effectively describe the distribution of bond lengths in each case. For a symmetrical, normal distribution, the mean (d) will be approximately equal to the median (m), the lower and upper quartiles ([q_l,q_u]) will be approximately symmetric about the median [m-q_l\simeq q_u-m], and 95% of the observations may be expected to lie within ±2σ of the mean value. For a skewed distribution, d and m may differ appreciably and [q_l] and [q_u] will be asymmetric with respect to m. When a bond-length distribution is negatively skewed, i.e. very short values are more common than very long values, then it may be due to thermal-motion effects; the distances used to prepare the table were not corrected for thermal libration.

In a number of cases, the initial bond-length distribution was clearly not unimodal as in Fig. 9.6.2.1(a)[link]. Where possible, such distributions were resolved into their unimodal components (as in Fig. 9.6.2.1c[link]) on chemical or structural criteria. The case illustrated in Fig. 9.6.2.1[link], for Cu—Cl bonds, is one of the most spectacular examples, owing to the dramatic consequences of oxidation state and coordination number (and Jahn–Teller effects) on the structures of copper complexes.

9.6.3. Content and arrangement of table of interatomic distances

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Table 9.6.3.1[link] indicates how the interatomic distances covered in Table 9.6.3.3[link] are subdivided. Metal–ligand distances are grouped according to the ligand contact atom, which leads to ordering by atomic number of that contact atom. For a given contact atom (H, B, C, etc.), the ligands are grouped by type as listed in Table 9.6.3.1[link]. The class of ligand is identified numerically (e.g. alkoxides are class 5.3, alcohols class 5.23, ethers 5.24, etc.). Particular ligands are identified by a third number (e.g. methoxide is ligand 5.3.1). Finally, alternative bonding modes for a particular ligand are denoted by a fourth number [e.g. terminal alkoxides 5.3.1.1, bridging (μ2) alkoxides 5.3.1.2]. In general, the bonding modes are arranged in the sequence [\eta^1, \eta^2, \ldots, \eta^n], [\mu_2,\mu_3], etc., where ηn implies n atoms of the ligand are bonded to metal atoms, and μm that m metal atoms are bonded to the ligand. Thus, acetates are represented by entries headed 5.5.2.1 (η1), 5.5.2.2 (chelating, η2) and 5.5.2.3 (bridging, μ2). For each ligand, the metal–ligand bonds then follow a sequence of ascending atomic number of the metal. For a given metal, the first line of an entry in Table 9.6.3.3[link] gives statistics covering all appropriate occurrences of metal–ligand distances. Further lines give statistics for metal–ligand distances for subdivision based largely on chemical criteria (e.g. metal oxidation state or coordination number). Cases where one atom of a ligand bridges two or more metal atoms were included only when the metal atoms were all of the same type and, unless specified, only when the metal–ligand distances were symmetrical (range for distances ≤ 0.1 Å).

Table 9.6.3.1| top | pdf |
Ligand index

Contact atomLigand classLigand class identifier
Hydrogen hydride 1.1
tetrahydroborate [({\rm BH}^{-}_{4})] 1.2
Boron borohydrides 2.1
boranes/carbaboranes 2.2
boroles, borylenes, other heteroboracycles 2.3
Carbon carbide (C) 3.1
carbyne/alkylidyne (CR) 3.2
vinylidene/alkenylidene (CCR2) 3.3
acetylide/alkynyl (CCR) 3.4
cyano (CN) 3.5
isocyanides (CNR) 3.6
carbon monoxide (CO) 3.7
thiocarbonyl (CS) 3.8
carbene/alkylidene (CR2) 3.9
vinyl/alkenyl (CRCR2) 3.10
aryl (C6R5) 3.11
acyl [C(O)R] 3.12
alkyl (CR3) 3.13
η-alkenes (C2R4, allenes, etc.) 3.14
alkynes (RCCR) 3.15
[\eta^3] ligands (allyls, etc.) 3.16
[\eta^4] ligands (conjugated dienes, etc.) 3.17
[\eta^5] ligands (dienyls, etc.) 3.18
[\eta^6] ligands (arenes, etc.) 3.19
[\eta^7, \eta^8] ligands 3.20
carbaboranes, boroles 3.21
miscellaneous (CO2, CS2, etc.) 3.22
Nitrogen nitride (N) 4.1
nitrene/imide (NR) 4.2
methyleneamido (N=CR2) 4.3
nitriles (NCR) 4.4
isocyanate, isothiocyanate (NCO, NCS) 4.5
dinitrogen (N2) 4.6
diazonium (N2R), diazoalkanes (N2CR2) 4.7
azide (N3) 4.8
nitrosyl, thionitrosyl (NO, NS) 4.9
amide (NR2) 4.10
amidinate [RNC(R)NR] 4.11
Schiff bases 4.12
phthalocyanines, porphyrins, pyrroles 4.13
pyrazolate, imidazolate and derivatives 4.14
pyridine, polypyridyls (bpy, o-phen) 4.15
pyrazines, pyridazines, pyrimidines 4.16
other N2 ligands (NRNR2, NNR2, NRNR) 4.17
triazenido (RNNNR) 4.18
hydrazones and related species (NR2N=CR) 4.19
oximes 4.20
N-nitrite (NO2) 4.21
amine (NR3) 4.22
borazines 4.23
Oxygen oxo (O) 5.1
hydroxy (OH) 5.2
alkoxy, aryloxy, etc. (OR) 5.3
O-ketones (OCR2), urea 5.4
carboxylates (O2CR) 5.5
oxalate (O2CCO2) 5.6
acetylacetonates [RC(O)CRC(O)CR] 5.7
α,β-diones (e.g. o-quinones) 5.8
carbonate [({\rm CO}^{2-}_3)] 5.9
N-oxides (e.g. pyridine N-oxide) 5.10
nitrate [({\rm NO}^-_3)] 5.11
O-nitrite [({\rm NO}^-_2)] 5.12
dioxygen, peroxides 5.13
phosphine oxides (OPR3) 5.14
phosphate [({\rm PO}^{3-}_4)] 5.15
other P—O anions 5.16
O-dialkyl sulfoxides (OSR2) 5.17
sulfate [({\rm SO}^{2-}_4)] 5.18
other S—O anions (sulfonates, etc.) 5.19
O-SO2 5.20
other oxyanions (e.g. [{\rm ClO}^-_4]) 5.21
aqua 5.22
alcohols (ROH) 5.23
ethers (ROR′) 5.24
miscellaneous ([\eta^2]-acyl, [\eta^2]-CO2, μ-NCO) 5.25
Fluorine fluoride (F) 6.1
fluoroanions ([{\rm BF}^-_4], [{\rm PF}^-_6]) 6.2
Silicon miscellaneous 7.1
Phosphorus phosphorus (P) 8.1
phosphinidenes (PR) 8.2
phosphides (PR2) 8.3
oligo-phosphorus ligands (P3, PR2PR2, PRPR, etc.) 8.4
phosphines (PR3) 8.5
diphosphines (e.g. diphos) 8.6
phosphites [P(OR)3] 8.7
aminophosphines, cyclotriphosphazenyl, misc. P—N ligands 8.8
Sulfur sulfides (S) 9.1
thiolates (SR) 9.2
S-thiocyanate (SCN) 9.3
thioketones, thiourea (S=CR2) 9.4
thiocarboxylates (S2CR) 9.5
thiocarbamates [({\rm S}_2{\rm CN}R^-_2)] 9.6
xanthates (S2COR), dithiocarbonates 9.7
trithiocarbonate [({\rm CS}^{2-}_3)], thioxanthates 9.8
α,β-dithiones 9.9
phosphine sulfides 9.10
dithiophosphinates [({\rm S}_2{\rm P}R^-_2)] 9.11
polysulfur ligands (S2, SSR, etc.) 9.12
thioethers (SR2) 9.13
S-SO2, S-SO3, etc. 9.14
disulfides (RSSR) 9.15
S-dialkyl sulfoxides (R2SO) 9.16
miscellaneous ([\eta^2]-CS2) 9.17
Chlorine chloride (Cl) 10.1
Arsenic arsines (AsR3) 11.1
miscellaneous 11.2
Selenium miscellaneous 12.1
Bromine bromide (Br) 13.1
Tellurium miscellaneous 14.1
Iodine iodide (I) 15.1
[Figure 9.6.3.1]

Figure 9.6.3.1 | top | pdf |

Diagrams of ligands in Table 9.6.3.3[link], showing table entry number and ligand atom labelling.

In many instances, the number of structures having inter-atomic distances involving a given metal for a particular ligand is too small (< 4) for statistics to be quoted. In these cases, individual structures, and the distances in them, are given. These structures are identified by their CSD reference code (e.g. BOZMIN); short-form literature references, ordered alphabetically by reference code, are in Appendix 9.6.2[link].

Each line of Table 9.6.3.3[link] contains nine columns of which six record the statistics of the bond-length distribution described above. The content of the remaining three columns: Bond, Substructure, and Note, are described below.

9.6.3.1. The `Bond' column

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This specifies the atom pair to which the line refers. Therefore, in the case of triethylphosphine complexes (section 8.5.2), there are 18 lines, in which the bond column contains P—C, followed by 17 entries for Ti—P through to Au—P, indicating statistics for both intraligand and metal–ligand atom pairs.

9.6.3.2. Definition of `Substructure'

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This column provides details of any subdivision of particular metal–ligand bonds that has been applied. Thus, for terminal iron–chlorine bonds (in section 10.1.1.1), the second and third lines of the Fe—Cl entry refer to complexes in which the iron atom is four-coordinate and in oxidation state II and III, respectively. In some cases, subdivision has been carried out on the basis of ligand substituents in those cases where a well defined subdistribution was observed. For clarity, in a number of cases the ligand structure and numbering scheme are illustrated in Fig. 9.6.3.1[link]. The reader will be aware that formal oxidation state is not always well defined, where no assignment was possible then this is indicated by (−) rather than the roman numeral used elsewhere. Finally, cases where the ligand oxidation state is variable are identified (e.g. for O2, o-quinones etc.) by references to the footnotes at the end of Table 9.6.3.3[link].

9.6.3.3. Use of the `Note' column

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The `Note' column refers to the footnotes collected in Appendix 9.6.1[link]. These record additional information as follows: (a) notable features of the distribution of distances, e.g. likely bias due to dominance by one structure of substructure, skewness, bimodality (subdivisions of the entry usually follow, which remove these features whenever possible); (b) further details of the chemical substructure, such as the exclusion of structures with particular trans ligands; (c) details of exclusion criteria used for a given entry or group of entries, such as the constraint that the two M—Cl distances, in bridging (μ2) chloride complexes, differ by < 0.1 Å (section 10.1.1.2); (d) references to previously published surveys of crystallographic results relevant to the entry in question. We do not claim that these entries are in any way comprehensive and we would be grateful to authors for notification (to AGO) of any omissions. This will serve to improve the content of any future version of Table 9.6.3.3[link].

9.6.3.4. Locating an entry in Table 9.6.3.3[link]

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Table 9.6.3.2[link] provides a `guide' to the contents of Table 9.6.3.3[link]. The number of entries for which individual examples of M—ligand distances are quoted, and the number of entries for which statistics are given in Table 9.6.3.3[link] are listed for each metal. Inspection of Table 9.6.3.2[link] shows which element pairs have no bond lengths recorded in Table 9.6.3.3[link]. Thus, while there are no cobalt–fluorine distances in Table 9.6.3.3[link], there are 6 classes of cobalt–phosphorus distances for which there are examples quoted and 10 for which statistics are given.

Table 9.6.3.2| top | pdf |
Numbers of entries in Table 9.6.3.3[link]

Numbers of entries for which < 4 examples are known are given first, followed by numbers of entries for which statistics are quoted (i.e. those with > 4 examples).

 Ligand atoms
HBCNOFSiPSClAsSeBrTeI
Ligand class54667179413249321313
Metal               
Sc1   1, 0 0, 1   0, 4                    
Ti2,3   2, 0 6, 8 14, 5 4, 15 1, 0   1, 2 4, 3 1, 2 1, 0   1, 0    
V4,5,6   2, 0 8, 8 6, 5 10, 10 0, 1   3, 3 2, 6 0, 2 1, 0       1, 0
Cr7 1, 0 1, 2 9, 15 12, 13 5, 19 0, 1   9, 5 1, 7 1, 1 0, 2 1, 0 2, 0 1, 0 1, 0
Mn   0, 3 15, 12 14, 13 14, 10 1, 0 1, 0 5, 6 7, 4 0, 2 0, 2 1, 0 1, 1 0, 1 1, 1
Fe 0, 2 1, 2 10, 33 13, 19 14, 12   0, 1 6, 13 7, 16 0, 2 0, 2 0, 1 2, 0 0, 1 1, 1
Co8 2, 0 0, 4 11, 27 5, 28 18, 22     6, 10 7, 11 1, 2 0, 2   0, 1   0, 1
Ni9,10 0, 1 2, 1 7, 20 9, 23 9, 18 1, 0   6, 8 12, 13 0, 2 1, 1 0, 1 0, 2   1, 1
Cu11,12 1, 0 3, 0 1, 11 7, 35 18, 31 3, 0   3, 3 7, 12 0, 3 0, 1 1, 0 0, 3   0, 3
Zn 1, 0 2, 0 3, 2 7, 16 14, 10       7, 3 0, 2     0, 1   0, 1
Y1   1, 0 0, 1   2, 6         0, 1          
Zr13   1, 0 6, 8 10, 1 5, 7 0, 1   1, 1 4, 0 0, 2   1, 0     1, 0
Nb14     4, 6 3, 5 2, 9 0, 1   2, 0 1, 6 1, 2 0, 1        
Mo15,16 1, 1 1, 0 11, 25 17, 26 7, 28 1, 1 1, 0 5, 11 3, 20 1, 2 0, 2 1, 0 0, 2 1, 0 0, 2
Tc17,18     0, 1 5, 5 3, 5     1, 2 1, 2 1, 1 0, 1   2, 0    
Ru 0, 1 2, 1 12, 25 19, 9 11, 8   0, 1 2, 13 4, 4 0, 2 0, 2   0, 2   1, 1
Rh 2, 1 0, 2 11, 25 12, 18 11, 14   1, 0 5, 13 6, 7 0, 2 1, 1 0, 1 0, 2   0, 2
Pd   0, 1 9, 15 14, 13 6, 6     8, 7 4, 10 1, 2 1, 1   0, 1   1, 1
Ag   1, 0 4, 2 8, 6 8, 2 1, 0   2, 3 4, 6 2, 1   1, 0 1, 0   1, 2
Cd19       3, 14 12, 10     2, 0 6, 4 0, 3     1, 2   0, 1
La§       1, 1 4, 7       1, 0 1, 0          
Ce§     0, 2 0, 1 4, 4       0, 1 1, 0          
Pr§     1, 1 1, 0 2, 5         2, 0          
Nd§       2, 2 7, 5         1, 0          
Sm§     0, 1 2, 1 8, 6                    
Eu§     0, 1 0, 1 3, 6                    
Gd§     0, 1 1, 0 2, 4                    
Tb§         1, 0                    
Dy§       2, 1 1, 2       0, 1            
Ho§         0, 1                    
Er§     0, 1 1, 1 4, 4         1, 0          
Tm§                 0, 1            
Yb§     0, 2 2, 2 3, 2         2, 0         1, 0
Lu§     1, 2 1, 0 0, 1       0, 1            
Hf13     2, 4 1, 0 2, 2     0, 2   1, 0          
Ta23 1, 0   5, 7 4, 1 4, 2     2, 2 2, 4 0, 2     1, 0    
W24,159 0, 2 1, 1 9, 20 10, 7 4, 12 1, 0 1, 0 4, 6 7, 5 1, 2 1, 0 1, 0 0, 1   1, 1
Re 0, 2 0, 1 10, 13 9, 9 11, 12 1, 0 0, 1 4, 5 4, 3 0, 2 0, 1 1, 0 0, 2   0, 2
Os 0, 2 2, 0 12, 11 9, 7 6, 6   1, 0 4, 6 3, 3 0, 2 1, 0 1, 0 1, 0   0, 1
Ir 1, 1 1, 1 11, 12 12, 4 3, 4 1, 0 1, 0 5, 9 5, 5 0, 2   1, 0 0, 2   0, 2
Pt 2, 0 0, 1 4, 25 11, 13 8, 10 1, 0 0, 1 6, 13 8, 11 0, 2 0, 1 1, 0 0, 2 1, 0 0, 2
Au25   0, 1 4, 3 6, 0 4, 0     5, 3 7, 3 0, 1     0, 1   1, 0
Hg26   1, 0 8, 3 10, 5 11, 2   0, 1 3, 2 2, 6 1, 2   1, 0 0, 2 0, 1 0, 2
Th§ 1, 0   1, 2 0, 3 5, 8     1, 0 0, 1 0, 1          
U§   0, 1 1, 5 7, 5 16, 18 1, 2   1, 0 1, 1 0, 2     0, 1    
No entries for Pm, Pa, and Ac.
Superscripts refer to entries in Appendix 9.6.1[link].
§See references 1, 20–23 in Appendix 9.6.1[link].

Table 9.6.3.3| top | pdf |
Interatomic distances (Å)

BondSubstructure (coordination number, oxidation state, comment)dmσqlqunNote
1.1.1.1 Hydrides (terminal) 27
Fe—H all BASLIQ10 1.609 1.610 0.004 1.605 1.612 6  
Zn—H see MAEMAZ11 (1.617)              
Mo—H see HCYPMO02 (1.684)              
Rh—H see CONFEQ01 (1.578, 1.583)              
Ta—H see TACPTH (1.769, 1.774, 1.776)              
W—H all IPPHWH01 1.732 1.734 0.010 1.725 1.740 6  
Re—H (8), (-) 1.684 1.681 0.015 1.676 1.697 12  
Os—H all THMPOS01 1.659 1.656 0.017 1.646 1.677 4  
Ir—H all DETSOK 1.603 1.607 0.021 1.582 1.623 5  
Pt—H see CAKNEH01 (1.610)              

BondSubstructure (coordination number, oxidation state, comment)dmσqlqunNote
1.1.1.2 Hydrides (μ2-H) 27
Cr—H see KCPTCR01 (1.725, 1.723)              
Fe—H all HMYCFE01 1.670 1.670 0.001 1.669 1.672 4  
Mo—H (6, 7), (II, III) 1.842 1.843 0.023 1.819 1.864 4  
Ru—H (), (-) 1.782 1.776 0.019 1.773 1.791 22  
Rh—H (4, ), (I) 1.775 1.768 0.040 1.738 1.811 8  
W—H (6), (0) 1.900 1.897 0.028 1.876 1.926 5  
Re—H (8, ), (I, IV) 1.832 1.832 0.039 1.793 1.870 16  
Os—H (), (-) 1.817 1.824 0.029 1.798 1.837 34  
Ir—H see CUSGAY (1.821, 1.847)              
Pt—H see CAKNEH01 (range 1.656–2.049)              

BondSubstructure (coordination number, oxidation state, comment)dmσqlqunNote
1.1.1.3 Hydrides (μ3-H) 27
Co—H see HMPCIC01 (1.728, 1.731, 1.742)              
Ni—H all TCPNIH11 1.691 1.684 0.022 1.673 1.715 9  
Rh—H see HMPCRH11 (1.847, 1.855, 1.873)              

BondSubstructure (coordination number, oxidation state, comment)dmσqlqunNote
1.2.1.1 BH4 [M—(μ2-H)—B] 28
Cu—H see TMPCUB01 (1.698)              

BondSubstructure (coordination number, oxidation state, comment)dmσqlqunNote
1.2.1.2 BH4 [M—(μ2-H)2—BH2]  
Co—H see BEGBIY01 (1.707, 1.740)              
Th—H see MCHFHB10 (2.069, 2.120)              

BondSubstructure (coordination number, oxidation state, comment)dmσqlqunNote
2.1.1 Borohydrides [M(—H—)BH2R] 28
Sc—B see BOVCAQ (2.528)              
Ti—B see CPCLBT (2.178)              
Cr—B see BOSKUP (2.294)              
Co—B (-), (I): (η2-BH4, μ21, η1′-BH4) 2.218 2.224 0.030 2.199 2.241 6  
Ni—B see YBAENI (3.088)              
Cu—B see BOLJAN (2.441), CICFID (2.204, 2.232), PHRLCU (2.079), TMPCUB01 (2.517)              
Zn—B see CAPFOO (2.219), NBCZNB10 (2.252, 2.253)              
Y—B see BUWBAW (2.478, 2.836), HBTHFY (2.574, 2.680)              
Zr—B see CANFAY (2.335)              
Mo—B see HBMPMO (2.468)              
Ru—B see CIZBOC (2.237)              
Os—B see COCKOU (2.300)              
U—B (-), (III, IV): all 2.569 2.510 0.136 2.494 2.644 16  
  (-), (IV): [(μ-H)3BR] 2.493 2.498 0.040 2.459 2.515 11  

BondSubstructure (coordination number, oxidation state, comment)dmσqlqunNote
2.2.1 Boranes/carbaboranes (not H-bridged) (see also 3.21.1) 29
Ti—B see CEXTII (2.355, 2.375, 2.383)              
V—B see BUPLAZ10 (2.246, 2.322, 2.333)              
Cr—B   2.228 2.252 0.054 2.178 2.266 9  
Mn—B   2.255 2.231 0.058 2.213 2.306 9  
Fe—B   2.140 2.135 0.066 2.103 2.179 111  
Co—B   2.086 2.082 0.073 2.036 2.124 270  
Ni—B   2.106 2.108 0.049 2.071 2.142 41  
Cu—B see BOTPCU (2.209, 2.237), TPCUBF (2.273)              
Ru—B :all 2.263 2.234 0.167 2.041 2.377 16 30
  :short < 2.10 2.035 2.033 0.012 2.026 2.046 5  
  :long > 2.25 2.367 2.355 0.067 2.318 2.399 11  
Rh—B   2.224 2.219 0.061 2.188 2.252 55  
Pd—B   2.237 2.244 0.041 2.197 2.260 10  
Ag—B see TPACUB (2.352, 2.420, 2.522)              
W—B   2.403 2.393 0.036 2.381 2.416 7  
Re—B   2.292 2.287 0.056 2.239 2.349 6  
Os—B see BUVROZ (2.147, 2.184, 2.283)              
Ir—B   2.236 2.205 0.083 2.183 2.287 29  
Pt—B   2.243 2.244 0.062 2.213 2.283 94  
Au—B   2.238 2.228 0.034 2.206 2.256 11  
Hg—B see COBHGA (2.201, 2.286), TPMCDB10 (2.204, 2.498, 2.521)              

BondSubstructure (coordination number, oxidation state, comment)dmσqlqunNote
2.2.2 Boranes/carbaboranes [M(—H—)B] (hydrogen located) 29
Mn—B   2.228 2.222 0.025 2.208 2.254 4  
Fe—B see TPCUBF (2.115)              
Co—B   2.100 2.086 0.032 2.079 2.125 15  
Cu—B see TPCUBF (2.164)              
Zn—B see CEXSAZ (2.264, 2.274)              
Ru—B see COKTIF (2.327, 2.462)              
Rh—B   2.342 2.330 0.040 2.311 2.384 4  
W—B see COVROU (2.413)              
Ir—B see BELJEH (2.290, 2.281), CTPIRB (2.250), TPICBO (2.452, 2.480)              

BondSubstructure (coordination number, oxidation state, comment)dmσqlqunNote
2.3.1 Boracycles (see also 3.21.2 and 4.23.1) 31–33
V—B see BOKXEE (2.369)              
Cr—B excluding BRNOCR (2.566) 2.340 2.349 0.026 2.312 2.360 7  
Mn—B   2.291 2.282 0.047 2.252 2.299 7  
Fe—B   2.227 2.185 0.097 2.163 2.279 13  
Co—B   2.123 2.097 0.076 2.073 2.189 12  
Ni—B see CIDBOG (2.411), CPBORN (2.175), FMBCNI (2.260), SIBONI (2.226), VIBONI (2.500, 2.550)              

BondSubstructure (coordination number, oxidation state, comment)dmσqlqunNote
3.1.1.1 Carbide (μ4-C) 34, 35
Hg—C see FAHGME (2.042)              

BondSubstructure (coordination number, oxidation state, comment)dmσqlqunNote
3.1.1.2 Carbide (μ5-C) 34, 35
Ru—C   2.049 2.043 0.057 2.004 2.084 40  
Os—C   2.060 2.056 0.059 2.004 2.108 35  

BondSubstructure (coordination number, oxidation state, comment)dmσqlqunNote
3.1.1.3 Carbide (μ6-C) 34, 35
Ru—C   2.060 2.063 0.023 2.040 2.076 60  
Rh—C see CBACRC (2.122, 2.132, 2.125)              

BondSubstructure (coordination number, oxidation state, comment)dmσqlqunNote
3.2.1.1 Carbyne/alkylidyne (terminal CR, R = any C) 36, 37
C—C   1.468 1.475 0.031 1.436 1.495 18  
Cr—C (6), (-) 1.702 1.710 0.029 1.679 1.720 5 38
Mo—C see BENFEF (1.799)              
Ta—C see BESPIY (1.850), TABYCP10 (1.849)              
W—C (5, 6), (IV, VI) 1.815 1.821 0.041 1.777 1.840 9  
Re—C see CECROR (1.742)              

BondSubstructure (coordination number, oxidation state, comment)dmσqlqunNote
3.2.1.2 Carbynes/alkylidynes (μ2-CR, R = any C, H) 39
C—C   1.480 1.478 0.030 1.452 1.510 4  
Ru—C see VCPRUB10 (1.933, 1.941), CIFXOE (1.936)              
W—C   1.955 1.947 0.021 1.940 1.973 6  

BondSubstructure (coordination number, oxidation state, comment)dmσqlqunNote
3.2.1.3 Carbynes/alkylidynes (μ3-CR, R = any C, H)    
C—C   1.510 1.505 0.025 1.494 1.526 21  
Fe—C   1.928 1.933 0.024 1.910 1.939 15  
Co—C   1.896 1.895 0.035 1.874 1.920 27  
Mo—C   2.059 2.056 0.019 2.042 2.075 11  
Ru—C   2.084 2.089 0.027 2.067 2.102 6  
Rh—C all R = H 1.964 1.970 0.020 1.945 1.980 7  
Os—C all COTPOQ01 2.101 2.102 0.004 2.097 2.105 6  

BondSubstructure (coordination number, oxidation state, comment)dmσqlqunNote
3.2.2.1 Amino carbynes (terminal CNR2)    
(M)C—N   1.322 1.334 0.053 1.271 1.368 5  
N—C   1.469 1.470 0.027 1.441 1.485 8  
Cr—C see BAMCOH (1.750), SNCOCR (1.743)              
Mo—C see BITKIY (1.797)              
W—C see CAVREW (1.776, 1.747)              

BondSubstructure (coordination number, oxidation state, comment)dmσqlqunNote
3.2.3.1 Thiocarbynes (terminal CSR)    
C—S (1.712, 1.713)              
Mo—C see CAWSAU (1.801)              
W—C see TPCPTW (1.810)              

BondSubstructure (coordination number, oxidation state, comment)dmσqlqunNote
3.3.1.1 Vinylidenes/alkenylidenes (terminal CCR2) 40
C=C   1.318 1.312 0.032 1.295 1.329 7  
Fe—C see COPMID (1.780, 1.799)              
Mo—C see BUJFIV (1.918), CVMOMP10 (1.833)              
Ru—C see BOJJUF (1.845)              
Rh—C see CAYMAQ (1.820)              
W—C see CEFVUE (1.983)              

BondSubstructure (coordination number, oxidation state, comment)dmσqlqunNote
3.3.1.2 Vinylidenes/alkenylidenes (μ2-CCR2)  
C=C   1.317 1.315 0.023 1.305 1.326 7  
Mn—C see EYCCMN (1.971, 1.978)              
Fe—C see CHPECI (1.969, 1.955)              
Co—C   1.885 1.885 0.021 1.864 1.904 4  
Ru—C see VCPRUA10 (2.025, 2.034)              
Rh—C see BECVOU (1.987, 1.989)              
Os—C see BEXJUJ (2.096, 2.102)              

BondSubstructure (coordination number, oxidation state, comment)dmσqlqunNote
3.4.1.1 Acetylides/alkynyls (terminal CCR)  
C[triple bond]C   1.188 1.188 0.017 1.178 1.202 16  
C—C   1.456 1.451 0.030 1.436 1.465 16  
V—C see CIJLUC (2.074)              
Fe—C see CPFPEY (1.920)              
Rh—C see BIMTEW (1.939)              
Pd—C see EYPIPD (1.953)              
W—C see BONSUS (2.134)              
Ir—C see CEFPEI (2.041)              
Pt—C (4, 6), (II, IV) 1.992 2.000 0.032 1.985 2.009 8 41
Hg—C see PEYHGP (2.047, 2.031)              

BondSubstructure (coordination number, oxidation state, comment)dmσqlqunNote
3.4.1.2 Acetylides/alkynyls (μ2-CCR)§ 42
C—C   1.231 1.232 0.026 1.206 1.256 4  
Fe—Cσ see ACYPCI (1.890)              
—Cπ (2.117, 2.283)              
Ru—Cσ see BAYCOS (2.047), BOBTOB (2.044)              
—Cπ see BAYCOS (2.323, 2.423); BOBTOB (2.285, 2.508)              
Pt—Cσ see MSIPEP (1.964)              
—Cπ see MSIPEP (2.141, 2.468)              

BondSubstructure (coordination number, oxidation state, comment)dmσqlqunNote
3.5.1.1 Cyano (terminal CN) 43
C—N   1.146 1.146 0.014 1.138 1.154 168  
V—C see CIRSAX (2.067), CIRSEB (2.088)              
Cr—C (6), (-): all 2.058 2.063 0.024 2.031 2.080 8 7
Mn—C see CAZJAO10 (1.996, 1.989)              
Fe—C (5, 6), (0, II, III): all 1.937 1.935 0.023 1.923 1.950 33  
Co—C (5, 6), (-): all 1.896 1.900 0.019 1.883 1.907 50 8
Ni—C (4, 5), (-): all 1.883 1.868 0.076 1.852 1.873 30  
  excluding 2 > 2.1 1.864 1.868 0.021 1.851 1.872 28  
Cu—C (3, 5), (-): all 2.003 1.975 0.101 1.924 2.098 5 12
Zn—C (4), (-): all 2.000 1.997 0.012 1.991 2.013 4  
Mo—C (6, 7, 8), (-): all 2.167 2.166 0.021 2.155 2.184 21 15, 44
Ru—C see BEPJIP (2.025)              
Pd—C see BEJHUT (1.997)              
Ag—C see COLSEB (2.093)              
Pt—C (4, 5), (II): all 1.943 1.931 0.031 1.916 1.977 5  
Au—C see CIGCOK (2.003)              
Hg—C see BINRAR (2.187, 2.174), CAHRUY (2.100)              

BondSubstructure (coordination number, oxidation state, comment)dmσqlqunNote
3.5.1.2 Cyano (μ2-CN)§ (see also 4.4.2)  
C—N   1.143 1.147 0.016 1.132 1.153 21  
Cr—C see CYCRTF (1.999, 1.972, 1.965)              
Mn—C see CAZJAO10 (1.995)              
Fe—C (6), (III) 1.948 1.942 0.025 1.928 1.972 6  
Ni—C (4), (II) 1.859 1.853 0.017 1.847 1.877 4  
Cu—C (4), (I) 1.951 1.965 0.030 1.914 1.974 6 12
Pd—C see BUSRIQ (2.011)              

BondSubstructure (coordination number, oxidation state, comment)dmσqlqunNote
3.6.1.1 Isocyanides (terminal CNR, R = any C) 45, 46
C—N   1.149 1.147 0.016 1.139 1.157 220  
V—C see CIRSAX (2.003), CLBCNV (2.189)              
Cr—C (6, 7), (0–III): R = Ph, tBu, Bz 1.996 2.003 0.038 1.969 2.014 21 7
Mn—C (6), (-): R = Ph, tBu, Me 1.927 1.924 0.028 1.900 1.947 15  
Fe—C (5, 6, ), (0–II): all 1.862 1.867 0.048 1.819 1.901 12  
  (6), (II): all 1.874 1.874 0.043 1.832 1.901 7  
Co—C see BISJOC (1.851, 1.846, 1.866)              
Ni—C (3, 4), (0): R = tBu 1.853 1.854 0.021 1.838 1.870 6  
Cu—C (3, 4), (I): R = tBu, p-Tol, cyh 1.896 1.895 0.009 1.890 1.905 7  
Nb—C (7, 8), (-): R = tBu 2.241 2.237 0.036 2.208 2.270 6  
Mo—C (5–8), (0–IV) 2.107 2.115 0.040 2.089 2.135 61 15
  (5–8), (II) 2.111 2.115 0.032 2.094 2.131 56  
  (5–7), (II): R = tBu 2.108 2.115 0.030 2.089 2.125 36  
Ru—C (6, ), (-) 1.986 1.997 0.040 1.941 2.014 7  
Rh—C (4–6), (-) 1.968 1.969 0.036 1.955 1.983 21  
  (4), (-) 1.956 1.962 0.031 1.947 1.975 13  
Pd—C (3–5), (-) 1.985 1.974 0.036 1.958 2.020 18 47
  (4), (-) 1.978 1.972 0.035 1.955 1.994 15  
Ag—C see BUXGAC (2.162, 2.136)              
Pr—C see CXINPR10 (2.654)              
W—C (7), (II): R = tBu 2.102 2.105 0.035 2.070 2.125 11  
Re—C (6, 7), (I–II) 2.002 2.008 0.022 1.980 2.018 12  
Os—C see CIRJAO (1.983, 2.004), HOSTBC10 (2.032)              
Ir—C see MCPEIR (1.945), MICPIR10 (1.986)              
Pt—C (4, 5, ), (-) 1.936 1.924 0.059 1.896 1.968 13  
  (4, 5), (-) 1.944 1.966 0.036 1.912 1.968 7  

BondSubstructure (coordination number, oxidation state, comment)dmσqlqunNote
3.6.1.2 Isocyanides (μ2-CNR)  
C—N   1.221 1.227 0.038 1.196 1.241 15  
Fe—C   1.941 1.941 0.025 1.920 1.948 12  
Ni—C all MINCNI 1.881 1.880 0.022 1.861 1.903 4  
Os—C see HYBIOS (2.072, 2.039)              
Pt—C all BIDCAS 2.100 2.086 0.070 2.038 2.170 12  

BondSubstructure (coordination number, oxidation state, comment)dmσqlqunNote
3.7.1.1 Carbon monoxide (terminal CO) 48
C—O   1.145 1.143 0.020 1.132 1.156 10022  
Ti—C   2.003 1.997 0.030 1.980 2.030 5 49
V—C   1.946 1.946 0.037 1.924 1.974 60  
Cr—C   1.866 1.867 0.037 1.835 1.895 925 38
Mn—C   1.808 1.805 0.034 1.784 1.833 789  
Fe—C   1.782 1.784 0.030 1.765 1.801 2572 50
Co—C   1.780 1.781 0.034 1.758 1.801 662  
Ni—C   1.771 1.776 0.029 1.750 1.794 34 51
Cu—C   1.787 1.782 0.019 1.776 1.807 18 12
Zr—C see CCPZRA (2.187)             49
Nb—C   2.073 2.073 0.028 2.056 2.092 26  
Mo—C   1.978 1.973 0.041 1.947 2.007 748 15
Tc—C   1.884 1.883 0.021 1.866 1.904 4 17
Ru—C   1.896 1.896 0.036 1.873 1.919 1453  
Rh—C   1.847 1.846 0.040 1.821 1.869 238  
Ta—C see BISZIM (2.036), BUVGII (2.083), CPMPTA (2.008)              
W—C   2.002 2.007 0.043 1.971 2.034 508 24
Re—C   1.936 1.933 0.050 1.898 1.978 370  
Os—C   1.902 1.903 0.036 1.880 1.927 1443  
Ir—C   1.870 1.876 0.042 1.839 1.898 148  
Pt—C   1.853 1.854 0.056 1.821 1.878 29  

BondSubstructure (coordination number, oxidation state, comment)dmσqlqunNote
3.7.1.2 Carbon monoxide (μ2-CO) 52
C—O   1.171 1.171 0.022 1.159 1.183 279  
Mn—C (all) 1.940 1.930 0.021 1.926 1.955 8  
  (M—C—M < 70°) 1.929 1.928 0.005 1.924 1.933 6  
Fe—C (all) 1.941 1.925 0.041 1.914 1.971 104  
  (M—C—M < 80°) 1.985 1.995 0.037 1.953 2.018 20  
  (80° < M—C—M < 86°) 1.930 1.921 0.034 1.908 1.946 80  
Co—C   1.914 1.919 0.046 1.883 1.947 114  
Ni—C   1.882 1.880 0.021 1.870 1.892 14  
Cu—C   1.861 1.862 0.015 1.854 1.872 6  
Mo—C (all) 2.127 2.091 0.095 2.045 2.237 6  
  (Mo=Mo only) 2.068 2.064 0.027 2.045 2.095 4  
Ru—C (all) 2.072 2.055 0.047 2.038 2.099 66  
  (non-clusters) 2.040 2.039 0.021 2.026 2.055 20  
  (clusters) 2.086 2.087 0.048 2.043 2.114 46  
Rh—C (all) 2.040 2.037 0.055 1.994 2.076 180  
  (M—C—M < 85°) 2.057 2.058 0.059 2.000 2.111 106  
  (85° < M—C—M < 95°) 2.018 2.029 0.037 1.984 2.046 68  
  (M—C—M > 115°) 1.983 1.982 0.007 1.977 1.990 4  
Pd—C (all) 2.004 1.997 0.039 1.979 2.015 14  
Re—C (all BAWTOI) 2.073 2.072 0.009 2.063 2.080 6  
Os—C   2.081 2.063 0.057 2.042 2.122 6  
Ir—C   2.065 2.072 0.039 2.026 2.093 30  
Pt—C   2.044 2.039 0.032 2.018 2.063 6  

BondSubstructure (coordination number, oxidation state, comment)dmσqlqunNote
3.7.1.3 Carbon monoxide (μ3-CO) 42
C—O   1.190 1.191 0.038 1.173 1.202 33  
Fe—C   2.002 1.990 0.037 1.980 1.997 15  
Co—C   1.950 1.949 0.032 1.937 1.962 15  
Ni—C see TCPDNI01 (1.931, 1.932)              
Ru—C   2.171 2.169 0.020 2.153 2.193 8  
Rh—C see POSHRH10 (2.205, 2.155, 2.238)              
Pd—C see BUJYIO (2.190, 2.078, 2.157)              

BondSubstructure (coordination number, oxidation state, comment)dmσqlqunNote
3.8.1.1 CS (terminal)  
C—S   1.563 1.570 0.030 1.536 1.587 5  
Cr—C see BUGRIE (1.778), MBZCRC (1.797), TLCSCR (1.751)              
Mn—C see ICPNMN (1.803)              
Fe—C see BEPDEF (1.662)              

BondSubstructure (coordination number, oxidation state, comment)dmσqlqunNote
3.8.1.2 CS (μ2-CS)  
C—S (1.597, 1.606, 1.618)              
Fe—C all CPTCFF 1.886 1.889 0.007 1.878 1.891 4  

BondSubstructure (coordination number, oxidation state, comment)dmσqlqunNote
3.9.1.1 Carbene/alkylidene (terminal CH2) 36
Re—C see CAHZUG (1.898)              
Os—C see CAMTEP (1.924)              

BondSubstructure (coordination number, oxidation state, comment)dmσqlqunNote
3.9.1.2 Carbenes/alkylidenes (μ2-CR2, R = any C, H) 39, 53
Mn—C see BANGIG10 (2.026), MYCCMN10 (2.018, 2.019)              
Fe—C   2.006 1.990 0.045 1.974 2.052 6  
Co—C   1.934 1.925 0.025 1.909 1.961 7  
Ru—C   2.085 2.095 0.056 2.076 2.112 12  
Rh—C   2.048 2.059 0.033 2.017 2.075 15  
W—C excluding BIJJAF (2.127, 2.436) 2.298 2.296 0.035 2.266 2.331 4  
Re—C all CEHFEA 2.141 2.132 0.030 2.119 2.171 4  
Os—C excluding CODCON (1.922, 1.909) 2.160 2.155 0.041 2.136 2.192 20  
Au—C   2.112 2.102 0.026 2.095 2.139 4  

BondSubstructure (coordination number, oxidation state, comment)dmσqlqunNote
3.9.2.1 Carbenes/alkylidenes (terminal CHR)  
C—C   1.490 1.493 0.027 1.462 1.513 14  
Ta—C (5, 6, 8), (V): all 1.963 1.938 0.065 1.932 2.030 7 54, 55
W—C (5–7), (IV, VI) 1.953 1.942 0.086 1.871 2.041 5 38, 55
Re—C see BOBYAS (1.949), CECROR (1.873)              

BondSubstructure (coordination number, oxidation state, comment)dmσqlqunNote
3.9.3.1 Carbenes/alkylidenes (terminal CR2)  
C—C [R = C (sp3)] 1.503 1.509 0.024 1.500 1.519 12  
Mn—C see CERJIS (1.853), MCBCMN (1.864, 1.871)              
Fe—C see CPCFEA10 (1.978)              
W—C see DPCBWC (2.132, 2.154)             38, 55
Ir—C see PYBPIR (1.998)              

BondSubstructure (coordination number, oxidation state, comment)dmσqlqunNote
3.9.4.1 Alkoxy carbenes [terminal CR(OR), R = any C]  
(M)C—O   1.318 1.314 0.023 1.300 1.338 18  
(M)C—C   1.501 1.503 0.032 1.479 1.524 18  
O—C   1.466 1.459 0.024 1.452 1.484 18  
Cr—C (6), (-) 2.012 2.006 0.029 1.988 2.039 5 38, 55
Mn—C see BOCWAR (1.848), MNXCMN (1.890), NPMCMN (1.950)             55
Co—C see PGECBC (1.912)              
Mo—C see BEBTUX (2.087)              
W—C (6), (-) 2.161 2.161 0.014 2.148 2.175 4  
Re—C see CMNCBR (2.098)              
Os—C see BODGUW10 (1.981)              
Pt—C see CIPTMN (1.889), EOBCPT10 (1.920)              

BondSubstructure (coordination number, oxidation state, comment)dmσqlqunNote
3.10.1.1 Vinyls (σ-CRCR2)§ 41
C=C   1.345 1.344 0.024 1.333 1.357 98  
Ti—C (8), (IV) 2.215 2.239 0.042 2.171 2.243 7  
Cr—C all MPEYCR10 2.035 2.033 0.009 2.027 2.045 4  
Mn—C see BIZJEZ (1.985), CECCIW (2.009), MASBCM (2.027)              
Fe—C (5, 6), (II) 1.991 1.997 0.039 1.954 2.030 10  
Co—C (6), (-) 1.934 1.932 0.019 1.914 1.946 8  
Ni—C (4, 5), (-) 1.892 1.900 0.017 1.874 1.903 4  
Zr—C see CPPHZR (2.249, 2.265)              
Mo—C (7), (-) 2.204 2.223 0.049 2.151 2.247 5  
Ru—C see CNBRUB (2.073), CXFMPR (2.082), PCFMRU10 (2.034)              
Rh—C   2.040 2.060 0.054 1.986 2.085 5  
Pd—C (4), (II) 2.000 2.006 0.024 1.989 2.011 16 47
Hf—C see CPTPHF (2.190, 2.219)              
W—C see BEDGAS (2.202), COPMEZ (2.275), MCTCEW (2.194)              
Os—C see CIRNOG (2.052)              
Ir—C (5, 6), (-) 2.071 2.073 0.044 2.036 2.103 6  
Pt—C (4,5), (-) 2.024 2.022 0.037 1.991 2.058 17 41
Au—C see BULPED (2.039, 2.045)              

BondSubstructure (coordination number, oxidation state, comment)dmσqlqunNote
3.10.1.2 Vinyls (η2-CRCR2)§  
Cα—Cβ   1.408 1.407 0.013 1.418 1.442 8  
Mo—Cα   1.936 1.937 0.020 1.917 1.954 4  
—Cβ   2.292 2.293 0.027 2.265 2.316 4  
W—Cα   1.918 1.907 0.030 1.898 1.949 4  
—Cβ   2.251 2.249 0.078 2.181 2.324 4  

BondSubstructure (coordination number, oxidation state, comment)dmσqlqunNote
3.10.1.3 Vinyls (μ21, η2-CRCR2)§ 39
Cα—Cβ   1.408 1.407 0.022 1.395 1.421 43  
Mn1—Cα see BOWYOB (2.058, 2.053)              
Mn2—Cα see BOWYOB (2.086, 2.102)              
—Cβ see BOWYOB (2.263, 2.263)              
Fel—Cα   1.996 2.004 0.036 2.000 2.009 8  
Fe2—Cα   2.102 2.095 0.039 2.079 2.111 8  
Fe2—Cβ   2.219 2.197 0.046 2.183 2.260 8  
Co1—Cα see BOCCOC (1.973, 1.968), BULYOW (1.981)              
Co2—Cα see BOCCOC (2.009, 2.011), BULYOW (1.995)              
—Cβ see BOCCOC (2.132, 2.115), BULYOW (2.127)              
Mo1—Cα see BEDDAP (2.151, 2.140), CAMKIK (2.141)              
Mo2—Cα see BEDDAP (2.181, 2.181), CAMKIK (2.232)              
—Cβ see BEDDAP (2.301, 2.301), CAMKIK (2.446)              
Ru1—Cα   2.079 2.075 0.043 2.060 2.089 13  
Ru2—Cα   2.221 2.227 0.057 2.191 2.260 13  
—Cβ   2.276 2.276 0.042 2.247 2.284 13  
Rh1—Cα see BATNIT (2.045), FMPENR (2.025, 2.028)              
Rh2—Cα see BATNIT (2.100), FMPENR (2.058, 2.102)              
—Cβ see BATNIT (2.222), FMPENR (2.139, 2.205)              
W1—Cα (6, 7), (0, II, IV): all 2.158 2.145 0.043 2.128 2.203 6  
W2—Cα (6), (IV): excluding 2.266, 2.124 2.412 2.412 0.034 2.380 2.445 4  
—Cβ (6), (II, IV): excluding 1 at 2.220 2.458 2.470 0.047 2.410 2.500 5  
Re1—Cα see COTFAS (2.170, 2.098)              
Re2—Cα see COTFAS (2.359, 2.255)              
—Cβ see COTFAS (2.352, 2.307)              
Os21Cα see CHVINO (2.108), HPETOS (2.154), UCHXOS (2.170)              
Os2—Cα see CHVINO (2.273), HPETOS (2.151), UCHXOS (2.188)              
—Cβ see CHVINO (2.362), HPETOS (2.300), UCHXOS (2.311)              

BondSubstructure (coordination number, oxidation state, comment)dmσqlqunNote
3.11.1.1 σ-Aryls (η1-Ar)§  
Cl—C2   1.396 1.396 0.021 1.381 1.409 398  
C2—C3   1.393 1.392 0.022 1.379 1.406 398  
C3—C4   1.378 1.379 0.025 1.364 1.395 399  
Ti—C see PFPBTI (2.135), PSIBTI (2.161)              
V—C (4, 6), (II, III) 2.114 2.115 0.012 2.102 2.124 4  
Cr—C (5, 6), (II, III) 2.075 2.072 0.019 2.061 2.089 10 38
Mn—C (6), (I) 2.064 2.059 0.021 2.044 2.083 6  
Fe—C (4, 6), (I, II) 2.031 2.022 0.062 1.985 2.065 6  
  (6), (I, II) 2.008 2.021 0.021 1.974 2.030 5  
Co—C see DMDECO01 (1.995), ETPSCO10 (1.997), TOPFCO10 (1.931)              
Ni—C (4, 5), (II, III) 1.917 1.929 0.038 1.893 1.942 18  
Cu—C see CODJIO (2.020)              
Mo—C (4, 5, 7), (0, II, IV): all 2.193 2.176 0.054 2.164 2.195 11 38
  (4, 5), (II, IV) 2.172 2.169 0.016 2.160 2.187 9  
Ru—C (5, 6), (II) 2.092 2.121 0.057 2.013 2.136 7  
Rh—C (5, 6), (II, III) 2.011 2.000 0.026 1.990 2.037 9  
Pd—C (4, ), (II): all 1.981 1.987 0.032 1.965 2.002 28 47
Lu—C see CILCUV (2.425, 2.427, 2.455)              
Ta—C (5), (V) 2.199 2.173 0.073 2.147 2.276 4  
Re—C see PHTPRE (2.024, 2.029)              
Os—C (6, ), (-) 2.090 2.092 0.032 2.058 2.120 4  
Ir—C (4–6, ), (I, III): all 2.070 2.067 0.038 2.043 2.092 17  
  (6), (III) 2.053 2.049 0.024 2.037 2.071 10  
Pt—C (4–6), (I, II, IV): all 2.049 2.061 0.046 2.033 2.079 35 41
  (4), (I, II) 2.055 2.062 0.039 2.043 2.079 28  
Au—C (2–4, ), (I, III): all 2.059 2.062 0.024 2.052 2.073 22  
  (2, 3), (I) 2.053 2.050 0.009 2.045 2.062 5  
  (4), (III) 2.062 2.068 0.031 2.055 2.081 13  
Hg—C (2–4, ), (II): all 2.086 2.088 0.040 2.054 2.120 24  
  (2, 3), (II) 2.053 2.057 0.027 2.040 2.075 12  
  (), (-): all BIPHHG 2.120 2.119 0.014 2.115 2.126 12  

BondSubstructure (coordination number, oxidation state, comment)dmσqlqunNote
3.12.1.1 Acyls [η1-C(O)R]§  
C=O   1.210 1.209 0.023 1.195 1.218 60  
Mn—C see PNMNCP (2.012), PYRMNC (2.076)              
Fe—C (6), (II) 1.997 2.004 0.033 1.967 2.028 18  
Co—C see BOBSUG (1.915), OXCOCP10 (2.055)              
Ni—C (4, 5), (II) 1.850 1.870 0.059 1.788 1.893 4  
Mo—C see BOLCIO10 (2.049), MABUMO10 (2.168)              
Ru—C see BEWMAR (2.091)              
Rh—C (5, 6), (III): all 1.995 1.996 0.031 1.969 2.006 10  
Pd—C (4), (II): all 1.982 1.992 0.029 1.951 2.002 4  
Re—C (6), (I) 2.190 2.183 0.027 2.175 2.214 7  
Os—C see BUYMAJ (2.161)              
Ir—C see NRBIRB (1.971), POIRID (2.067)              
Pt—C (4), (II) 1.991 2.000 0.025 1.969 2.008 7  

BondSubstructure (coordination number, oxidation state, comment)dmσqlqunNote
3.12.1.2 Acyls [η2-C(O)R]§ (see also 5.25.1)  
C=O   1.240 1.238 0.014 1.227 1.248 10  
Zr—C see BOPSII (2.181, 2.186)              
Mo—C   2.014 2.020 0.011 2.003 2.023 6  
W—C see BUSYIX (2.030), COSSOS (2.000)              

BondSubstructure (coordination number, oxidation state, comment)dmσqlqunNote
3.13.1.1 Methyl (terminal CH3)  
Ti—C see BASMOX (1.969), INDMTI (2.206)              
Cr—C see CAMVER (2.168)              
Mn—C (6), (IV): all CAJHOK 2.095 2.105 0.030 2.068 2.124 4  
Fe—C see BNTLFE (2.080), CEDMON (2.065), CMZTFE (2.077)             50
Co—C (6), (III) 2.014 2.014 0.023 1.993 2.032 16  
Ni—C see BAPKEI (2.035), PEAMNI (2.023)             56
Zr—C IV, (4–6, 8) 2.292 2.279 0.049 2.257 2.346 8  
Nb—C see CPSNBA (2.346), CPSNBB (2.327)             54
Mo—C (5–7), (II–IV, VI): all 2.254 2.282 0.065 2.189 2.296 15  
Ru—C (5, 6), (II) 2.179 2.156 0.045 2.143 2.226 5  
Rh—C (5, 6), (II, III) 2.092 2.101 0.027 2.064 2.113 4  
Hf—C (8), (IV) 2.275 2.267 0.049 2.233 2.325 4  
Ta—C (6, 7), (III, V) 2.217 2.215 0.035 2.181 2.247 7 54
W—C (4–6), (II, III, VI) 2.189 2.187 0.039 2.166 2.213 13  
Re—C (5, 6), (I, III) 2.173 2.188 0.051 2.123 2.201 8  
Ir—C see BEJBEX (2.218), CODPIR10 (2.133)              
Pt—C (4–6), (II, IV): all 2.083 2.077 0.045 2.047 2.117 58 41
  (4, 5), (II) 2.107 2.115 0.044 2.069 2.136 30  
  (6), (IV) 2.057 2.056 0.028 2.038 2.077 28  
Au—C (4), (III) 2.066 2.045 0.045 2.030 2.118 18 57
Hg—C (2–4), (II) 2.072 2.071 0.026 2.056 2.092 29  
Th—C see COSZOZ (2.567)              

BondSubstructure (coordination number, oxidation state, comment)dmσqlqunNote
3.13.2.1 Primary alkyls [CH2R, R = C(sp3)]  
C—C   1.521 1.528 0.033 1.512 1.540 90  
Ti—C see BILWIC (2.138, 2.152), BOYZOE (2.210)              
Mn—C (4, 6), (I, II) 2.176 2.173 0.024 2.154 2.199 5  
Fe—C (6), (II) 2.091 2.082 0.030 2.071 2.102 8  
Co—C (6), (II, III) 2.039 2.037 0.032 2.018 2.061 14  
Ni—C see ACTPEN (1.970), BENIIB (1.973), DIPNIP (1.948)             56
Zn—C see PMCZNE (1.964)              
Nb—C see CPETNB (2.316), ONBCBU (2.322)             54
Mo—C (4–8), (II–IV, VI): all 2.250 2.252 0.061 2.208 2.272 12  
  (4–8), (III, IV, VI) 2.230 2.234 0.042 2.195 2.269 10  
Ru—C (4), (III): all CIBGEZ 2.036 2.033 0.010 2.029 2.045 6  
Rh—C see CIDJEE (2.094), PBUDRI10 (2.098, 2.107)              
Pd—C see BIHLOT01 (2.051), HIMPDA (2.009, 2.023)              
Ta—C (5, 7), (V) 2.225 2.208 0.056 2.183 2.289 6 54
W—C see COPXIO (2.141, 2.126), DMPMPW10 (2.257)              
Re—C see COMPRH (2.285), ETDYRE (2.296)              
Os—C see BOTTAF (2.220, 2.219), BUYNEO (2.203)              
Pt—C (4–6), (II, IV) 2.062 2.065 0.031 2.039 2.085 14 41
Hg—C see CIRMAR (2.125)              

BondSubstructure (coordination number, oxidation state, comment)dmσqlqunNote
3.13.3.1 Primary alkyl [CH2R, R = C(sp2)]  
C—C   1.477 1.478 0.028 1.464 1.496 108  
Ti—C see CEYCOY (2.203, 2.204)              
Cr—C see BELTUH (2.101)              
Mn—C see ACPMNA (2.209), BUFLET (2.199), CABYUZ (2.127)              
Fe—C (5, 6), (0, II) 2.131 2.133 0.038 2.098 2.155 9  
Co—C (5, 6), (-) 2.061 2.085 0.061 2.001 2.109 5  
Ni—C see IPRNIP (1.977)             56
Zn—C see CLPDZN (2.030)              
Zr—C (8), (IV) 2.320 2.306 0.034 2.298 2.355 4  
Nb—C (8), (IV, V) 2.289 2.291 0.024 2.271 2.306 14 54
Mo—C (4–6), (II, III, VI) 2.211 2.214 0.027 2.187 2.233 9  
Ru—C see CALHIG (2.200)              
Rh—C see CIHYOH (2.103)              
Pd—C (4, 5, ), (II, -) 2.050 2.044 0.042 2.019 2.071 20  
Hf—C see CEYCUE (2.274, 2.284)              
Ta—C see CBZYTA (2.304), CPBZTB (2.188, 2.233)             54
W—C (5–8), (II, III, V): all 2.238 2.185 0.090 2.163 2.328 9  
Re—C see BUVSOA (2.203), BZHREC (2.284)              
Os—C see BUYMAJ (2.217)              
Ir—C see BIYJIC (2.127), CIYKAW (2.167), POIRID (2.133)              
Pt—C (4, 5), (II) 2.067 2.081 0.033 2.032 2.089 4 41
Hg—C see CHGACA (2.107), DBEZHG (2.064)              
Th—C all CEKGEE 2.554 2.555 0.022 2.535 2.570 7  
U—C (6, 10), (IV) 2.509 2.521 0.039 2.468 2.539 4  

BondSubstructure (coordination number, oxidation state, comment)dmσqlqunNote
3.13.4.1 Secondary alkyls [terminal CHR2, R = C(sp3)]  
C—C   1.532 1.534 0.033 1.510 1.554 72  
Fe—C see BULLFE (2.168), CAGKEA (2.060), MEDOFE10 (2.079)              
Co—C (6), (III) 2.086 2.090 0.028 2.058 2.111 4  
Ni—C see CONBIQ (1.929)             56
Zr—C see CALNUY (2.381)              
Ru—C (5, 6), (II) 2.145 2.153 0.032 2.112 2.171 4  
Rh—C see HBUPRH (2.083)              
Pd—C (4, 5), (II) 2.035 2.041 0.036 2.003 2.051 9  
Ir—C (5, 6), (III) 2.107 2.107 0.035 2.074 2.141 7  
Pt—C (4, 5), (II) 2.078 2.073 0.038 2.046 2.116 4 41
Hg—C see CHGALD (2.085)              

BondSubstructure (coordination number, oxidation state, comment)dmσqlqunNote
3.13.5.1 Secondary alkyls {CHR2, R2 ≠ [C(sp3)2]}  
C—C R = C(sp2) 1.474 1.475 0.023 1.461 1.485 82  
  R = C(sp3) 1.532 1.527 0.022 1.518 1.545 40  
Ti—C see TCYPTI10 (2.332)              
Fe—C (5, 6), (-) 2.131 2.138 0.027 2.110 2.151 16  
Co—C (6), (-) 2.075 2.086 0.029 2.052 2.093 5  
Zr—C see PDPMZR10 (2.379, 2.396)              
Mo—C see BIRLIX (2.405)              
Ru—C see BDMFRU (2.180), CTERUC (2.138)              
Rh—C see BIGHAA (2.192), CASDIJ (2.154)              
Pd—C (4, 5), (II) 2.083 2.092 0.040 2.052 2.106 11  
Re—C (6), (I) 2.311 2.335 0.065 2.243 2.356 4  
Os—C see BUYNEO (2.221), CINKAL (2.215), EYPCOS (2.185)              
Ir—C see CAYGAK (2.420)              
Pt—C (4, 5), (II) 2.113 2.120 0.036 2.082 2.141 9 41
Au—C see BAJZAN (2.146), CEPYIF (2.175)             57
Hg—C see BAVMUG (2.122), TPHGDI10 (2.292)              

BondSubstructure (coordination number, oxidation state, comment)dmσqlqunNote
3.13.6.1 Tertiary alkyls (terminal CR3, R = any C)  
C—C   1.501 1.502 0.045 1.468 1.534 84 109
Fe—C (5, 6), (II) 2.127 2.128 0.027 2.098 2.153 6  
Co—C see COJBOS (2.154)              
Zn—C see COPLEY (2.050)              
Mo—C see CYPRMO (2.414)              
Pd—C (4), (II) 2.147 2.150 0.040 2.140 2.174 8  
Pt—C (4), (II) 2.148 2.139 0.028 2.133 2.162 9 41
Au—C see BENNOX (2.213), BUJXAF (2.197)             57

BondSubstructure (coordination number, oxidation state, comment)dmσqlqunNote
3.13.7.1 Trifluoromethyl (terminal CF3)  
C—F   1.347 1.343 0.030 1.329 1.355 22  
Pt—C (4, 5), (II) 2.098 2.087 0.057 2.056 2.146 5  

BondSubstructure (coordination number, oxidation state, comment)dmσqlqunNote
3.14.1 η2-Ethene (C2H4)  
C=C   1.392 1.390 0.044 1.363 1.415 43  
Co—C (5), (I) 2.035 2.033 0.012 2.025 2.048 4  
Ni—C (3, 4), (0) 1.985 1.978 0.025 1.970 1.989 18  
Cu—C (3, 4), (I) 2.010 2.011 0.011 2.001 2.019 6 12
Nb—C see CPETNB (2.278, 2.320)             54
Ru—C (6), (II) 2.198 2.204 0.022 2.174 2.215 4  
Rh—C (4, 5), (I) 2.129 2.135 0.033 2.091 2.160 12  
Ta—C see NPNTAB (2.228, 2.285)             54
W—C (5, 6), (-) 2.205 2.185 0.043 2.176 2.246 8  
Ir—C see CETPIR (2.124, 2.111)              
Pt—C (3, 4, ), (0, II) 2.172 2.176 0.042 2.143 2.193 28 41, 58

BondSubstructure (coordination number, oxidation state, comment)dmσqlqunNote
3.14.2 η2-Alkenes (CH2CHR, R = any C) 59
C=C   1.383 1.383 0.033 1.361 1.404 44  
Fe—C (5), (0) 2.090 2.088 0.012 2.079 2.102 4 58, 60
Co—C (5), (I) 2.084 2.085 0.034 2.052 2.115 4  
Ni—C (4, 5), (II) 2.035 2.039 0.053 1.984 2.082 4 9, 58, 61
Cu—C (3, ), (I) 2.060 2.061 0.025 2.046 2.080 6 12
Mo—C (6), (0, II) 2.282 2.271 0.027 2.265 2.310 4  
Ru—C (5, 6), (-) 2.198 2.190 0.034 2.171 2.232 4  
Rh—C (4, 6), (I, -) 2.172 2.164 0.058 2.118 2.216 10  
  (4), (I) 2.150 2.141 0.040 2.117 2.194 8  
Pd—C (4, 5), (II) 2.189 2.179 0.040 2.151 2.233 12  
Ag—C (3–5), (I) 2.535 2.542 0.050 2.486 2.582 6  
W—C (6), (0): all 2.386 2.410 0.080 2.302 2.454 10 30
  : short < 2.35 (trans to C=C) 2.299 2.298 0.010 2.290 2.308 4  
  : long > 2.40 (trans to CO) 2.443 2.434 0.036 2.412 2.484 6  
Ir—C see COPNIR (2.179, 2.162)              
Pt—C (4), (II) 2.179 2.173 0.051 2.139 2.205 22 41

BondSubstructure (coordination number, oxidation state, comment)dmσqlqunNote
3.14.3 η-Alkenes (CH2CR2, R = any C)  
C=C   1.387 1.396 0.029 1.354 1.413 8  
Fe—C (5), (0) 2.124 2.119 0.065 2.072 2.188 6 60
Ru—C see BOVLUT (2.168, 2.203)              
Pd—C see CARJOU (2.187, 2.107)              
Ag—C all CIXYAJ 2.421 2.419 0.081 2.345 2.499 4  

BondSubstructure (coordination number, oxidation state, comment)dmσqlqunNote
3.14.4 η2-Alkenes (CHRCHR, R = any C) 62
C=C   1.391 1.389 0.032 1.372 1.407 280  
V—C see EFMCPV (2.213, 2.186)              
Cr—C see MOBOCO10 (2.248, 2.300)              
Mn—C see CPTOMN (2.193, 2.203)              
Fe—C (5, 6), (0, II): all 2.134 2.143 0.063 2.079 2.183 22  
  : R electron withdrawing 2.067 2.072 0.022 2.041 2.087 8  
  : R = alkyl 2.172 2.169 0.041 2.144 2.195 14  
Co—C all NBPCCO 2.138 2.137 0.005 2.134 2.144 4  
Ni—C (3–5), (0, II): all 2.057 2.054 0.050 2.000 2.095 17 9, 58, 61
  : R electron withdrawing 1.991 1.997 0.015 1.979 2.000 5  
  :1,5-cod 2.084 2.089 0.028 2.052 2.107 12  
Cu—C (3, 4, ), (I): all 2.079 2.079 0.033 2.063 2.089 20 12
Mo—C (6), (0, II) : all 2.369 2.347 0.083 2.298 2.446 28  
  : trans to CO 2.468 2.463 0.039 2.428 2.499 10  
  : not trans to CO 2.314 2.310 0.034 2.284 2.346 18  
Ru—C : all 2.223 2.196 0.076 2.172 2.251 64 63
  : nbd, 1,5-cod only 2.191 2.187 0.036 2.167 2.206 49  
Rh—C (4–6, ), (I–III): all 2.157 2.143 0.049 2.123 2.188 206  
  : nbd, 1,5-cod only 2.156 2.143 0.047 2.122 2.189 184  
Pd—C (4), (II) 2.214 2.208 0.037 2.194 2.221 30  
Ag—C see BUZMUE (2.705, 2.611)              
W—C (6), (-) 2.430 2.430 0.033 2.400 2.457 6  
Re—C see BAXLER (2.275)              
Os—C : all R electron withdrawing 2.167 2.176 0.033 2.133 2.193 4  
Ir—C (4–6, ), (I, III): all 2.170 2.160 0.061 2.124 2.200 94  
  : 1,5-cod only 2.163 2.160 0.051 2.124 2.186 76  
Pt—C (4, 5, ), (0, II): all 2.209 2.223 0.056 2.173 2.252 52 41, 58
  : 1,5-cod only 2.230 2.236 0.039 2.193 2.254 40  

BondSubstructure (coordination number, oxidation state, comment)dmσqlqunNote
3.14.5 η2-Alkenes (CHRCR2, R = any C)  
C=C   1.411 1.403 0.025 1.392 1.427 12  
Mo—C see OCTCMO10 (2.211, 2.227)              
Ru—C see CXFMPR (2.171, 2.184)              
Rh—C (4, 5), (I) 2.130 2.121 0.023 2.111 2.155 14  
Ir—C all COTFEW 2.148 2.150 0.020 2.130 2.165 4  
Pt—C see COTFPT (2.059, 2.072)             41, 58

BondSubstructure (coordination number, oxidation state, comment)dmσqlqunNote
3.14.6 η2-Alkenes (CR2CR2, R = any C)  
C=C   1.436 1.438 0.044 1.415 1.454 15  
Fe—C : all 2.144 2.085 0.127 2.048 2.269 8  
  : excluding trans to CO 2.079 2.058 0.045 2.045 2.121 6  
Co—C see EXPHCO (2.084, 2.134)              
Mo—C see CPOMOA (2.231, 2.234)              
Rh—C (4, 5), (I) 2.175 2.173 0.025 2.153 2.199 4  
Pd—C (4), (II) 2.248 2.258 0.055 2.191 2.296 4  
Ag—C see BUGGAL (2.472, 2.632)              
Ir—C see IRCNIR (2.098, 2.130)              
Pt—C   2.130 2.128 0.026 2.106 2.156 4 41, 58
Hg—C see BODYEY (2.556, 2.577)              

BondSubstructure (coordination number, oxidation state, comment)dmσqlqunNote
3.14.7.1 η2-Allenes (R2CCCR2)§  
Cα=Cβ (coordinated) 1.403 1.403 0.028 1.375 1.431 5  
Cβ=Cγ (free) 1.319 1.321 0.010 1.311 1.327 5  
Fe—Cα see FPCYTP10 (1.982)              
—Cβ see FPCYTP10 (1.897)              
Rh—Cα see MARHAA10 (2.177, 2.178)              
—Cβ see MARHAA10 (2.032, 2.027)              
Pd—Cα see ALETPD (2.118)              
—Cβ see ALETPD (2.068)              
Pt—Cα see MALLPT (2.107)             41
—Cβ see MALLPT (2.049)              

BondSubstructure (coordination number, oxidation state, comment)dmσqlqunNote
3.15.1.1 Alkynes (η2-C2R2, R = any C) 64
C[triple bond]C all 1.285 1.287 0.030 1.269 1.299 73  
  2e donor 1.269 1.271 0.034 1.242 1.284 23  
  3e donor 1.285 1.292 0.024 1.268 1.299 15  
  4e donor 1.304 1.309 0.027 1.280 1.321 15  
V—C see CPFVLV (2.076)              
Cr—C all PHACCS 1.960 1.960 0.009 1.952 1.969 6  
Mn—C see HDYCMN (1.239)              
Co—C see ACNCOB20 (1.977, 1.981), BETCUY10 (1.847, 1.856)              
Cu—C (3), (1): R = SiMe3, H 2.019 2.020 0.029 1.994 2.043 5 12
Nb—C (6, 8), (III): R = Ph 2.082 2.054 0.061 2.041 2.148 8 54
Mo—C varying electron donation (2–4e): all 2.078 2.072 0.050 2.043 2.143 40 65
  2e donor 2.129 2.131 0.031 2.099 2.148 12  
  3e donor 2.071 2.066 0.033 2.053 2.082 12  
  4e donor 2.027 2.035 0.028 1.997 2.049 12  
Rh—C : R = Ph, CF3 2.041 2.045 0.015 2.030 2.051 6  
Pd—C see FMEACA10 (2.040, 2.053)              
Ta—C   2.059 2.064 0.024 2.032 2.079 6 54
W—C varying electron donation (2–4e): all 2.060 2.059 0.036 2.034 2.083 36 65
  2e donor 2.080 2.076 0.041 2.059 2.104 14  
  3e donor 2.066 2.066 0.016 2.053 2.078 12  
  4e donor 2.025 2.022 0.014 2.013 2.036 10  
Re—C   2.043 2.042 0.022 2.029 2.063 6  
Ir—C   2.083 2.083 0.041 2.044 2.122 4  
Pt—C   2.025 2.029 0.016 2.020 2.037 18 41

BondSubstructure (coordination number, oxidation state, comment)dmσqlqunNote
3.15.1.2 Alkynes (μ22, η2′-C2R2)§ 64
C[triple bond]C   1.353 1.355 0.031 1.337 1.365 29  
Co—C   1.954 1.940 0.033 1.930 1.966 47  
Ni—C all FLCPNI 1.910 1.909 0.011 1.901 1.921 4 61
Mo—C   2.171 2.178 0.050 2.137 2.199 32  
Rh—C all CFBYRH 2.054 2.056 0.029 2.026 2.081 4  
Ta—C see ACTHTA (2.217, 2.418)              
W—C all: (show twisting from C2vC2) 2.122 2.099 0.102 2.050 2.214 12  
  excluding CAMLAD 2.117 2.099 0.059 2.086 2.158 8  

BondSubstructure (coordination number, oxidation state, comment)dmσqlqunNote
3.15.1.3 Alkynes (μ21, η1′-C2R2)§ 64
C[triple bond]C   1.315 1.316 0.024 1.301 1.340 14  
Co—C see CAHHAU (2.066)              
Ru—C   2.084 2.091 0.016 2.068 2.094 4  
Rh—C   2.021 2.001 0.041 1.992 2.064 6  
Ir—C   2.112 2.109 0.041 2.082 2.156 8  
Pt—C   2.059 2.056 0.009 2.051 2.068 5 41

BondSubstructure (coordination number, oxidation state, comment)dmσqlqunNote
3.16.1 η3-Allyls (R2C.CR.CR2)§  
C1—C2