Dyscrasite (Ag$_{3.15}$Sb$_{0.85}$) Structure: A3B_oP4_25_abc_d-001
| Prototype | Ag$_{3}$Sb |
| AFLOW prototype label | A3B_oP4_25_abc_d-001 |
| Mineral name | dyscrasite |
| ICSD | 64698 |
| CCDC | 1626881 |
| Pearson symbol | oP4 |
| Space group number | 25 |
| Space group symbol | $Pmm2$ |
| AFLOW prototype command |
aflow --proto=A3B_oP4_25_abc_d-001
--params=$a, \allowbreak b/a, \allowbreak c/a, \allowbreak z_{1}, \allowbreak z_{2}, \allowbreak z_{3}, \allowbreak z_{4}$ |
- We have reordered the Wyckoff positions of this structure to match the AFLOW standard. What (Scott, 1976) designated as the Sb (1a) site is now (1d). That site is actually 85% antimony and 15% silver.
- Space group $Pmm2$ #25 allows an arbitary choice of the origin of the $z$-axis. We set $z_{1} = 0$ for the (1a) site.
\[ \begin{array}{ccc}
\mathbf{a_{1}}&=&a \,\mathbf{\hat{x}}\\\mathbf{a_{2}}&=&b \,\mathbf{\hat{y}}\\\mathbf{a_{3}}&=&c \,\mathbf{\hat{z}}
\end{array}\]
Basis vectors
| Lattice coordinates | Cartesian coordinates | Wyckoff position | Atom type | |||
|---|---|---|---|---|---|---|
| $\mathbf{B_{1}}$ | = | $z_{1} \, \mathbf{a}_{3}$ | = | $c z_{1} \,\mathbf{\hat{z}}$ | (1a) | Ag I |
| $\mathbf{B_{2}}$ | = | $\frac{1}{2} \, \mathbf{a}_{2}+z_{2} \, \mathbf{a}_{3}$ | = | $\frac{1}{2}b \,\mathbf{\hat{y}}+c z_{2} \,\mathbf{\hat{z}}$ | (1b) | Ag II |
| $\mathbf{B_{3}}$ | = | $\frac{1}{2} \, \mathbf{a}_{1}+z_{3} \, \mathbf{a}_{3}$ | = | $\frac{1}{2}a \,\mathbf{\hat{x}}+c z_{3} \,\mathbf{\hat{z}}$ | (1c) | Ag III |
| $\mathbf{B_{4}}$ | = | $\frac{1}{2} \, \mathbf{a}_{1}+\frac{1}{2} \, \mathbf{a}_{2}+z_{4} \, \mathbf{a}_{3}$ | = | $\frac{1}{2}a \,\mathbf{\hat{x}}+\frac{1}{2}b \,\mathbf{\hat{y}}+c z_{4} \,\mathbf{\hat{z}}$ | (1d) | Sb I |
References
- J. D. Scott, Refinement of the crystal structure of dyscrasite, and its implications for the structure of allargentum, Can. Mineral. 14, 139–142 (1976).
Found in
- R. T. Downs and M. Hall-Wallace, The American Mineralogist Crystal Structure Database, Am. Mineral. 88, 247–250 (2003).
First cited in
- N. Anderson, M. J. Mehl, H. Eckert, S. Divilov, X. Campilongo, S. Curtarolo, The AFLOW Library of Crystallographic Prototypes: Part 5. Submitted to Computational Materials Science (2026).
Geometry files
Prototype Generator
aflow --proto=A3B_oP4_25_abc_d --params=$a,b/a,c/a,z_{1},z_{2},z_{3},z_{4}$