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

International Tables for Crystallography (2006). Vol. C, ch. 3.3, p. 161

Section 3.3.4. Media for organic substances

E. S. Larsen Jr,a R. Meyrowitzb and A. J. C. Wilsonc

aUS Geological Survey, Washington 25, DC, and Harvard University, Cambridge, MA, USA,bUS Geological Survey, Washington 25, DC, USA, and cSt John's College, Cambridge, CB2 1TP, England

3.3.4. Media for organic substances

| top | pdf |

Organic substances are usually soluble in organic liquids, but not usually in aqueous solutions. The saturated solutions listed in Table 3.3.4.1[link] (Jelley, 1934[link], p. 245) are generally satisfactory. For substances of low solubility, the organic liquids listed in Table 3.3.4.2[link] may be useful; the refractive index of diluted aqueous solutions changes with time because of evaporation.

Table 3.3.4.1| top | pdf |
Aqueous solutions for use as immersion media for organic crystals

Salt[n^{20^\circ \rm C}_D] of saturated solution
Lithium iodide 1.490
Sodium iodide 1.496
Potassium iodide 1.456
Barium iodide 1.528
Tetrasodium dioxypentathiostannate 1.615

Table 3.3.4.2| top | pdf |
Organic immersion media for use with organic crystals of low solubility

Compound[n^{20^\circ \rm C}_D]
Diethyl oxalate 1.41
Di-n-butyl carbonate 1.41
Triethyl citrate 1.44
Tri-n-butyl citrate 1.44
n-Butyl phthalate 1.49
α-Bromonaphthalene 1.66
α-Iodonaphthalene 1.70
Methylene iodide 1.74

If the index of refraction is greater than about 1.7, the media at the end of Table 3.3.2.1[link] have to be used. These usually dissolve organic crystals, so that the immersion liquid becomes saturated with the compound. The refractive index of the saturated medium is then measured with a microrefractometer (Jelley, 1934[link], pp. 236–240).

References

Jelley, E. E. (1934). A microfractometer and its use in chemical microscopy. J. R. Microsc. Soc. 54, 234–245.








































to end of page
to top of page