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

International Tables for Crystallography (2006). Vol. C, ch. 1.3, p. 13

Table 1.3.4.1 

E. Kocha

aInstitut für Mineralogie, Petrologie und Kristallographie, Universität Marburg, Hans-Meerwein-Strasse, D-35032 Marburg, Germany

Table 1.3.4.1| top | pdf |
Possible twin operations for twins by merohedry

m is the index of the point group in the corresponding holohedry; point groups allowing twins of type 2 are marked by an asterisk.

HolohedryBravais latticePoint groupmPossible twin operations
1 aP 1 2 [\bar 1]
2/m mP, mS 2 2 [\bar 1]
m 2 [\bar 1]
mmm oP, oS, oI, oF 222 2 [\bar1]
mm2 2 [\bar 1]
4/mmm tP, tI [^*4] 4 [\bar1, .m., .2.]
[^*\bar4] 4 [\bar1, .m.,.2.]
[^*4/m] 2 [.m.]
422 2 [\bar 1]
[4mm] 2 [\bar 1]
[\bar42m/\bar4m2] 2 [\bar 1]
[\bar3m] hR [^*3] 4 [\bar1, .m, .2]
[^*\bar3] 2 .m
32 2 [\bar1]
3m 2 [\bar1]
6/mmm hP [^*3] 8 [\bar1], .m., .2., m.., ..m, 2.., ..2
[^*\bar3] 4 .m., m.., ..m
[^*321/312] 4 [\bar1,m..,..2/.2.]
[^*3m1/31m] 4 [\bar1,m..,..m/.m.]
[^*\bar3m1/\bar31m] 2 m..
[^*6] 4 [\bar1,.m., .2.]
[^*\bar6] 4 [\bar1, .m., ..m]
[^*6/m] 2 .m.
622 2 [\bar1]
6mm 2 [\bar1]
[\bar62m/\bar6m2] 2 [\bar1]
[m\bar3m] cP, cI, cF [^*23] 4 [\bar1, ..m,..2]
[^*m\bar3] 2 ..m
432 2 [\bar1]
[\bar43m] 2 [\bar1]