CaIn$_{2}$ Structure: AB2_hP6_194_b_f-001
| Prototype | CaIn$_{2}$ |
| AFLOW prototype label | AB2_hP6_194_b_f-001 |
| ICSD | 619376 |
| Pearson symbol | hP6 |
| Space group number | 194 |
| Space group symbol | $P6_3/mmc$ |
| AFLOW prototype command |
aflow --proto=AB2_hP6_194_b_f-001
--params=$a, \allowbreak c/a, \allowbreak z_{2}$ |
Other compounds with this structure
CaIn$_{2}$, EuIn$_{2}$, EuTl$_{2}$, SrIn$_{2}$, SrTl$_{2}$, YGa$_{2}$, YbIn$_{2}$
- (Iandelli, 1964) sets $z_{2} = 0.205$, but the distances quoted in the paper are consistent with $z_{2} = 1/4 - 0.205 = 0.045$. This value is confirmed in the quoted ICSD entry, attributed to (Bruzzone, 1964).
- When $z_{2}=0$ this structure reduces to the AlB$_{2}$ ($C32$), aka the hexagonal $\omega$ phase.
- CaIn$_{2}$ and hexagonal NbS$_{2}$ have the same AFLOW label, AB2_hP6_194_b_f. The structures are generated by the same symmetry operations with different sets of parameters (
--params) specified in their corresponding CIF files.
\[ \begin{array}{ccc}
\mathbf{a_{1}}&=&\frac{1}{2}a \,\mathbf{\hat{x}}- \frac{\sqrt{3}}{2}a \,\mathbf{\hat{y}}\\\mathbf{a_{2}}&=&\frac{1}{2}a \,\mathbf{\hat{x}}+\frac{\sqrt{3}}{2}a \,\mathbf{\hat{y}}\\\mathbf{a_{3}}&=&c \,\mathbf{\hat{z}}
\end{array}\]
Basis vectors
| Lattice coordinates | Cartesian coordinates | Wyckoff position | Atom type | |||
|---|---|---|---|---|---|---|
| $\mathbf{B_{1}}$ | = | $\frac{1}{4} \, \mathbf{a}_{3}$ | = | $\frac{1}{4}c \,\mathbf{\hat{z}}$ | (2b) | Ca I |
| $\mathbf{B_{2}}$ | = | $\frac{3}{4} \, \mathbf{a}_{3}$ | = | $\frac{3}{4}c \,\mathbf{\hat{z}}$ | (2b) | Ca I |
| $\mathbf{B_{3}}$ | = | $\frac{1}{3} \, \mathbf{a}_{1}+\frac{2}{3} \, \mathbf{a}_{2}+z_{2} \, \mathbf{a}_{3}$ | = | $\frac{1}{2}a \,\mathbf{\hat{x}}+\frac{\sqrt{3}}{6}a \,\mathbf{\hat{y}}+c z_{2} \,\mathbf{\hat{z}}$ | (4f) | In I |
| $\mathbf{B_{4}}$ | = | $\frac{2}{3} \, \mathbf{a}_{1}+\frac{1}{3} \, \mathbf{a}_{2}+\left(z_{2} + \frac{1}{2}\right) \, \mathbf{a}_{3}$ | = | $\frac{1}{2}a \,\mathbf{\hat{x}}- \frac{\sqrt{3}}{6}a \,\mathbf{\hat{y}}+c \left(z_{2} + \frac{1}{2}\right) \,\mathbf{\hat{z}}$ | (4f) | In I |
| $\mathbf{B_{5}}$ | = | $\frac{2}{3} \, \mathbf{a}_{1}+\frac{1}{3} \, \mathbf{a}_{2}- z_{2} \, \mathbf{a}_{3}$ | = | $\frac{1}{2}a \,\mathbf{\hat{x}}- \frac{\sqrt{3}}{6}a \,\mathbf{\hat{y}}- c z_{2} \,\mathbf{\hat{z}}$ | (4f) | In I |
| $\mathbf{B_{6}}$ | = | $\frac{1}{3} \, \mathbf{a}_{1}+\frac{2}{3} \, \mathbf{a}_{2}- \left(z_{2} - \frac{1}{2}\right) \, \mathbf{a}_{3}$ | = | $\frac{1}{2}a \,\mathbf{\hat{x}}+\frac{\sqrt{3}}{6}a \,\mathbf{\hat{y}}- c \left(z_{2} - \frac{1}{2}\right) \,\mathbf{\hat{z}}$ | (4f) | In I |
References
- A. Iandelli, MX$_2$-Verbindungen der Erdalkali- und Seltenen Erdmetalle mit Gallium, Indium und Thallium, Z. Anorganische und Allgemeine Chemie 330, 221–232 (1964), doi:10.1002/zaac.19643300315.
- G. Bruzzone and A. F. Ruggiero, The Equilibrium Diagram of the Calcium-Indium System, J. Less-Common Met. 7, 368–372 (1964), doi:10.1016/0022-5088(64)90081-5.
Found in
- W. B. Pearson, The Crystal Chemistry and Physics of Metals and Alloys (Wiley Interscience, New York, London, Sydney, Tornoto, 1972).
Prototype Generator
aflow --proto=AB2_hP6_194_b_f --params=$a,c/a,z_{2}$