International
Tables for Crystallography Volume C Mathematical, physical and chemical tables Edited by E. Prince © International Union of Crystallography 2006 |
International Tables for Crystallography (2006). Vol. C. ch. 1.2, pp. 6-9
https://doi.org/10.1107/97809553602060000573 Chapter 1.2. Application to the crystal systems
E. Kocha
a Institut für Mineralogie, Petrologie und Kristallographie, Universität Marburg, Hans-Meerwein-Strasse, D-35032 Marburg, Germany In this chapter, all general formulae from Chapter 1.1 Keywords: crystal systems; crystals; cubic crystal system; hexagonal crystal system; monoclinic crystal system; orthorhombic crystal system; rhombohedral crystal system; tetragonal crystal system; triclinic crystal system; trigonal crystal system. |
Information on the description and classification of Bravais lattices, their assignment to crystal systems, the choice of basis vectors for reduced or conventional basis systems, and on basis transformations is given in IT A (2005, Parts 5
and 9
). In the following, for each crystal system, the metrical conditions for conventionally chosen basis systems and the possible Bravais types of lattices are listed. As some of the general formulae from Chapter 1.1
become simpler when not applied to a lattice with general (triclinic) metric, these simplified formulae are tabulated for all crystal systems (except triclinic).
Except for triclinic, monoclinic, and orthorhombic symmetry, tables are given that relate pairs h, k or triplets h, k, l of indices to certain sums s of products of these indices needed in equation (1.1.2.2
). Such tables may be useful, for example, for indexing powder diffraction patterns.
No metrical conditions: a, b, c, α, β, γ arbitrary
Bravais lattice type: aP
Symmetry of lattice points:
Bravais lattice types: mP, mS
Symmetry of lattice points: 2/m
Metrical conditions: a, b, c, β arbitrary; α = γ = 90°
Bravais lattice types: mP, mC or mA or mI
Symmetry of lattice points: .2/m.
Metrical conditions: a, b, c arbitrary; α = β = γ = 90°
Bravais lattice types: oP, oS (oC, oA), oI, oF
Symmetry of lattice points: mmm
Metrical conditions: a = b; c arbitrary; α = β = γ = 90°
Bravais lattice types: tP, tI
Symmetry of lattice points: 4/mmm
Simplified formulae:
with
For each value of
, all corresponding pairs h, k are listed in Table 1.2.4.1
.
|
Metrical conditions: a = b; c arbitrary; α = β = 90°; γ = 120°
Bravais lattice types: hP, hR
Symmetry of lattice points: 6/mmm (hP), (hR)
Simplified formulae:
with
For each value of
, all corresponding pairs h, k are listed in Table 1.2.5.1
.
|
Metrical conditions: a = b = c; α = β = γ
Bravais lattice type: hR
Symmetry of lattice points:
Simplified formulae:
with
For each value of
, all corresponding values of
and all triplets h, k, l are listed in Table 1.2.5.2
.
|
Metrical conditions: a = b = c; α = β = γ = 90°
Bravais lattice types: cP, cI, cF
Symmetry of lattice points:
Simplified formulae:
with
For each value of
, all corresponding triplets h, k, l are listed in Table 1.2.6.1
.
|
References
