ThH$_{2}$ ($L'2_{b}$) Structure: A2B_tI6_139_d_a-001
| Prototype | H$_{2}$Th |
| AFLOW prototype label | A2B_tI6_139_d_a-001 |
| Strukturbericht designation | $L'2_{b}$ |
| ICSD | 24623 |
| Pearson symbol | tI6 |
| Space group number | 139 |
| Space group symbol | $I4/mmm$ |
| AFLOW prototype command |
aflow --proto=A2B_tI6_139_d_a-001
--params=$a, \allowbreak c/a$ |
Other compounds with this structure
SiPt$_{2}$, TiH$_{2}$, ZrH$_{2}$, Pt$_{2}$Si (LT)
- This structure was given the extended Strukturbericht label $L'2_{b}$ by (Pearson, 1967). It did not appear in the original Strukturbericht volumes. We had previously followed (Villars, 1991) and (Westbrook, 1995) and gave it the label $L'2$, however this conflicts with the label for the $L'2_{0}$
martensite
structure, so we will now use the original label.
\[ \begin{array}{ccc}
\mathbf{a_{1}}&=&- \frac{1}{2}a \,\mathbf{\hat{x}}+\frac{1}{2}a \,\mathbf{\hat{y}}+\frac{1}{2}c \,\mathbf{\hat{z}}\\\mathbf{a_{2}}&=&\frac{1}{2}a \,\mathbf{\hat{x}}- \frac{1}{2}a \,\mathbf{\hat{y}}+\frac{1}{2}c \,\mathbf{\hat{z}}\\\mathbf{a_{3}}&=&\frac{1}{2}a \,\mathbf{\hat{x}}+\frac{1}{2}a \,\mathbf{\hat{y}}- \frac{1}{2}c \,\mathbf{\hat{z}}
\end{array}\]
Basis vectors
| Lattice coordinates | Cartesian coordinates | Wyckoff position | Atom type | |||
|---|---|---|---|---|---|---|
| $\mathbf{B_{1}}$ | = | $0$ | = | $0$ | (2a) | Th I |
| $\mathbf{B_{2}}$ | = | $\frac{3}{4} \, \mathbf{a}_{1}+\frac{1}{4} \, \mathbf{a}_{2}+\frac{1}{2} \, \mathbf{a}_{3}$ | = | $\frac{1}{2}a \,\mathbf{\hat{y}}+\frac{1}{4}c \,\mathbf{\hat{z}}$ | (4d) | H I |
| $\mathbf{B_{3}}$ | = | $\frac{1}{4} \, \mathbf{a}_{1}+\frac{3}{4} \, \mathbf{a}_{2}+\frac{1}{2} \, \mathbf{a}_{3}$ | = | $\frac{1}{2}a \,\mathbf{\hat{x}}+\frac{1}{4}c \,\mathbf{\hat{z}}$ | (4d) | H I |
References
- R. E. Rundle, C. G. Shull, and E. O. Wollan, The crystal structure of thorium and zirconium dihydrides by X-ray and neutron diffraction, Acta Cryst. 5, 22–26 (1952), doi:10.1107/S0365110X52000071.
- W. B. Pearson, A Handbook of Lattice Spacings and Structures of Metals and Alloys, Volume 2, International Series of Monographs on Metal Physics and Physical Metallurgy, vol. 8 (Pergamon Press, Oxford, London, Edinburgh, New York, Toronto, Sydney, Paris, Braunschweig, 1967).
- P. Villars and L. Calvert, Pearson's Handbook of Crystallographic Data for Intermetallic Phases (ASM International, Materials Park, OH, 1991), 2nd edn.
- J. H. Westbrook and R. L. Fleischer, eds., Intermetallic Compounds – Principles and Practice (John Wiley & Sons, Ltd., Chichester, England, 1995). Two Volumes.
Prototype Generator
aflow --proto=A2B_tI6_139_d_a --params=$a,c/a$