(Ba,Ca)CO$_{3}$ ($C2$
) Structure: ABC3_mC10_5_b_a_ac-001
| Prototype | BaCCaO$_{3}$ |
| AFLOW prototype label | ABC3_mC10_5_b_a_ac-001 |
| ICSD | 403432 |
| Pearson symbol | mC10 |
| Space group number | 5 |
| Space group symbol | $C2$ |
| AFLOW prototype command |
aflow --proto=ABC3_mC10_5_b_a_ac-001
--params=$a, \allowbreak b/a, \allowbreak c/a, \allowbreak \beta, \allowbreak y_{1}, \allowbreak y_{2}, \allowbreak y_{3}, \allowbreak x_{4}, \allowbreak y_{4}, \allowbreak z_{4}$ |
- (Ba,Ca)(CO$_{3}$)$_{2}$ comes in a variety of crystal structures (Spahr, 2019):
- monoclinic barytocalcite, space group $P2_1/m$ #11
- trigonal paralstonite, space group $P321$ #150,
- triclinic alstonite (space group $P1$ #1 or $P\overline{1}$ #2) (Sartori, 1975), and
- a new monoclinic structure, space group $C2$ #5, synthesized by (Spahr, 2019), and lacking the centrosymmetric character of barytocalcite (the current structure).
- We used the data using the
HT synthesis
results of (Spahr, 2019) while the ICSD entry uses theprecipitation syntheis
results. This makes the two CIF files slightly different. - The site we have labeled Ba is actually a mixture of barium and calcium atoms.
\[ \begin{array}{ccc}
\mathbf{a_{1}}&=&\frac{1}{2}a \,\mathbf{\hat{x}}- \frac{1}{2}b \,\mathbf{\hat{y}}\\\mathbf{a_{2}}&=&\frac{1}{2}a \,\mathbf{\hat{x}}+\frac{1}{2}b \,\mathbf{\hat{y}}\\\mathbf{a_{3}}&=&c \cos{\beta} \,\mathbf{\hat{x}}+c \sin{\beta} \,\mathbf{\hat{z}}
\end{array}\]
Basis vectors
| Lattice coordinates | Cartesian coordinates | Wyckoff position | Atom type | |||
|---|---|---|---|---|---|---|
| $\mathbf{B_{1}}$ | = | $- y_{1} \, \mathbf{a}_{1}+y_{1} \, \mathbf{a}_{2}$ | = | $b y_{1} \,\mathbf{\hat{y}}$ | (2a) | C I |
| $\mathbf{B_{2}}$ | = | $- y_{2} \, \mathbf{a}_{1}+y_{2} \, \mathbf{a}_{2}$ | = | $b y_{2} \,\mathbf{\hat{y}}$ | (2a) | O I |
| $\mathbf{B_{3}}$ | = | $- y_{3} \, \mathbf{a}_{1}+y_{3} \, \mathbf{a}_{2}+\frac{1}{2} \, \mathbf{a}_{3}$ | = | $\frac{1}{2}c \cos{\beta} \,\mathbf{\hat{x}}+b y_{3} \,\mathbf{\hat{y}}+\frac{1}{2}c \sin{\beta} \,\mathbf{\hat{z}}$ | (2b) | Ba I |
| $\mathbf{B_{4}}$ | = | $\left(x_{4} - y_{4}\right) \, \mathbf{a}_{1}+\left(x_{4} + y_{4}\right) \, \mathbf{a}_{2}+z_{4} \, \mathbf{a}_{3}$ | = | $\left(a x_{4} + c z_{4} \cos{\beta}\right) \,\mathbf{\hat{x}}+b y_{4} \,\mathbf{\hat{y}}+c z_{4} \sin{\beta} \,\mathbf{\hat{z}}$ | (4c) | O II |
| $\mathbf{B_{5}}$ | = | $- \left(x_{4} + y_{4}\right) \, \mathbf{a}_{1}- \left(x_{4} - y_{4}\right) \, \mathbf{a}_{2}- z_{4} \, \mathbf{a}_{3}$ | = | $- \left(a x_{4} + c z_{4} \cos{\beta}\right) \,\mathbf{\hat{x}}+b y_{4} \,\mathbf{\hat{y}}- c z_{4} \sin{\beta} \,\mathbf{\hat{z}}$ | (4c) | O II |
References
- D. Spahr, L. Bayarjargal, V. Vinograd, R. Luchitskaia, V. Milman, and B. Winkler, A new BaCa(CO$_{3}$)$_{2}$ polymorph, Acta Crystallogr. Sect. B 75, 291–300 (2019), doi:10.1107/S2052520619003238.
- F. Sartori, New data on alstonite, Lithos 8, 199–207 (1975).
Prototype Generator
aflow --proto=ABC3_mC10_5_b_a_ac --params=$a,b/a,c/a,\beta,y_{1},y_{2},y_{3},x_{4},y_{4},z_{4}$