MgCuAl2 ($E1_{a}$) Structure : A2BC_oC16_63_f_c_c
| Prototype | : | Al2CuMg |
| AFLOW prototype label | : | A2BC_oC16_63_f_c_c |
| Strukturbericht designation | : | $E1_{a}$ |
| Pearson symbol | : | oC16 |
| Space group number | : | 63 |
| Space group symbol | : | $Cmcm$ |
| AFLOW prototype command | : | aflow --proto=A2BC_oC16_63_f_c_c --params=$a$,$b/a$,$c/a$,$y_{1}$,$y_{2}$,$y_{3}$,$z_{3}$ |
Other compounds with this structure
- YNiAl2, TaBCo2, ScNiAl2, LaPdIn2, $RE$–CuPd2 ($RE$ = Ce, Pr, Nd, Sm), CaNiGa2, PPdNi2, EuIrSn2, EuPdIn2, EuPdSn2, YbAuIn2, and YbPdIn2
- This is often referred to as an `S–phase precipitate'. It can be considered as the ternary version of the Re3B structure.
Base-centered Orthorhombic primitive vectors:
\[ \begin{array}{ccc} \mathbf{a}_1 & = & \frac12 \, a \, \mathbf{\hat{x}} - \frac12 \, b \, \mathbf{\hat{y}} \\ \mathbf{a}_2 & = & \frac12 \, a \, \mathbf{\hat{x}} + \frac12 \, b \, \mathbf{\hat{y}} \\ \mathbf{a}_3 & = & c \, \mathbf{\hat{z}} \\ \end{array} \]
Basis vectors:
\[ \begin{array}{ccccccc} & & \text{Lattice Coordinates} & & \text{Cartesian Coordinates} &\text{Wyckoff Position} & \text{Atom Type} \\ \mathbf{B}_{1} & = & -y_{1} \, \mathbf{a}_{1} + y_{1} \, \mathbf{a}_{2} + \frac{1}{4} \, \mathbf{a}_{3} & = & y_{1}b \, \mathbf{\hat{y}} + \frac{1}{4}c \, \mathbf{\hat{z}} & \left(4c\right) & \text{Cu} \\ \mathbf{B}_{2} & = & y_{1} \, \mathbf{a}_{1}-y_{1} \, \mathbf{a}_{2} + \frac{3}{4} \, \mathbf{a}_{3} & = & -y_{1}b \, \mathbf{\hat{y}} + \frac{3}{4}c \, \mathbf{\hat{z}} & \left(4c\right) & \text{Cu} \\ \mathbf{B}_{3} & = & -y_{2} \, \mathbf{a}_{1} + y_{2} \, \mathbf{a}_{2} + \frac{1}{4} \, \mathbf{a}_{3} & = & y_{2}b \, \mathbf{\hat{y}} + \frac{1}{4}c \, \mathbf{\hat{z}} & \left(4c\right) & \text{Mg} \\ \mathbf{B}_{4} & = & y_{2} \, \mathbf{a}_{1}-y_{2} \, \mathbf{a}_{2} + \frac{3}{4} \, \mathbf{a}_{3} & = & -y_{2}b \, \mathbf{\hat{y}} + \frac{3}{4}c \, \mathbf{\hat{z}} & \left(4c\right) & \text{Mg} \\ \mathbf{B}_{5} & = & -y_{3} \, \mathbf{a}_{1} + y_{3} \, \mathbf{a}_{2} + z_{3} \, \mathbf{a}_{3} & = & y_{3}b \, \mathbf{\hat{y}} + z_{3}c \, \mathbf{\hat{z}} & \left(8f\right) & \text{Al} \\ \mathbf{B}_{6} & = & y_{3} \, \mathbf{a}_{1}-y_{3} \, \mathbf{a}_{2} + \left(\frac{1}{2} +z_{3}\right) \, \mathbf{a}_{3} & = & -y_{3}b \, \mathbf{\hat{y}} + \left(\frac{1}{2} +z_{3}\right)c \, \mathbf{\hat{z}} & \left(8f\right) & \text{Al} \\ \mathbf{B}_{7} & = & -y_{3} \, \mathbf{a}_{1} + y_{3} \, \mathbf{a}_{2} + \left(\frac{1}{2} - z_{3}\right) \, \mathbf{a}_{3} & = & y_{3}b \, \mathbf{\hat{y}} + \left(\frac{1}{2}-z_{3}\right)c \, \mathbf{\hat{z}} & \left(8f\right) & \text{Al} \\ \mathbf{B}_{8} & = & y_{3} \, \mathbf{a}_{1}-y_{3} \, \mathbf{a}_{2}-z_{3} \, \mathbf{a}_{3} & = & -y_{3}b \, \mathbf{\hat{y}}-z_{3}c \, \mathbf{\hat{z}} & \left(8f\right) & \text{Al} \\ \end{array} \]References
- B. Heying, R.–D. Hoffmann, and R. Pöttgen, Structure Refinement of the S–Phase Precipitate MgCuAl2, Z. Naturforsch. B 60, 491–494 (2005), doi:10.1515/znb-2005-0502.