In ($A6$) Structure: A_tI2_139_a-001
Other compounds with this structure
Cr, La
- The indium ($A6$) and protactinium ($A_{a}$) structures have the same AFLOW prototype label, A_tI2_139_a. They are generated by the same symmetry operations with different sets of parameters (
--params) specified in their corresponding CIF files. - The ICSD lists both structures under the high-pressure Sn(tI2) structure type. We instead follow the Strukturbericht designation and assign structures with $c/a > 1$ to $A6$ while $A_{a}$ has $c/a < 1$.
- We did not find an ICSD entry for (Deshpande, 1969) so we used the ICSD entry from (Ridley, 1965). (Deshpande, 1969) report a = 4.6002Å and c = 4.9463Å while (Ridley, 1965) reports a = 4.5994Å and c = 4.9461Å, so the two lattices are practically indistinguishable.
- Our report of this structure in (Mehl, 2017) stated that (Deshpande, 1969) reported this structure in a face-centered tetragonal lattice. This is an error dating back to the original Crystal Lattice Structures page. The lattice constants are those of the standard conventional unit cell of a body-centered tetragonal lattice. We thank Bochuan Sun of Hampton University for pointing this out.
\[ \begin{array}{ccc}
\mathbf{a_{1}}&=&- \frac{1}{2}a \,\mathbf{\hat{x}}+\frac{1}{2}a \,\mathbf{\hat{y}}+\frac{1}{2}c \,\mathbf{\hat{z}}\\\mathbf{a_{2}}&=&\frac{1}{2}a \,\mathbf{\hat{x}}- \frac{1}{2}a \,\mathbf{\hat{y}}+\frac{1}{2}c \,\mathbf{\hat{z}}\\\mathbf{a_{3}}&=&\frac{1}{2}a \,\mathbf{\hat{x}}+\frac{1}{2}a \,\mathbf{\hat{y}}- \frac{1}{2}c \,\mathbf{\hat{z}}
\end{array}\]
Basis vectors
| Lattice coordinates | Cartesian coordinates | Wyckoff position | Atom type | |||
|---|---|---|---|---|---|---|
| $\mathbf{B_{1}}$ | = | $0$ | = | $0$ | (2a) | In I |
References
- V. T. Deshpande and R. R. Pawar, Anisotropic Thermal Expansion of Indium, Acta Crystallogr. Sect. A 25, 415–416 (1969), doi:10.1107/S0567739469000830.
- N. Ridley, Densities of some indium solid solutions, J. Less-Common Met. 8, 354–358 (1965), doi:10.1016/0022-5088(65)90071-8.
- M. J. Mehl, D. Hicks, C. Toher, O. Levy, R. M. Hanson, G. Hart, and S. Curtarolo, The AFLOW Library of Crystallographic Prototypes: Part 1, Comput. Mater. Sci. 136, S1–S828 (2017), doi:10.1016/j.commatsci.2017.01.017.
Found in
- J. Donohue, The Structures of the Elements (Robert E. Krieger Publishing Company, New York, 1974).
First cited in
- M. J. Mehl, D. Hicks, C. Toher, O. Levy, R. M. Hanson, G. L. W. Hart, and S. Curtarolo, The AFLOW Library of Crystallographic Prototypes: Part 1, Comp. Mat. Sci. 136, S1-S828 (2017). (doi=10.1016/j.commatsci.2017.01.017)
Geometry files
Prototype Generator
aflow --proto=A_tI2_139_a --params=$a,c/a$