Encyclopedia of Crystallographic Prototypes

AFLOW Prototype: A2BC2_hP5_164_d_a_d-001

This structure originally had the label A2BC2_hP5_164_d_a_d. Calls to that address will be redirected here.

If you are using this page, please cite:
D. Hicks, M.J. Mehl, M. Esters, C. Oses, O. Levy, G.L.W. Hart, C. Toher, and S. Curtarolo, The AFLOW Library of Crystallographic Prototypes: Part 3, Comp. Mat. Sci. 199, 110450 (2021). (doi=10.1016/j.commatsci.2021.110450)

Links to this page

https://aflow.org/p/N2MR
or https://aflow.org/p/A2BC2_hP5_164_d_a_d-001
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Brucite [Mg(OH)$_{2}$] Structure: A2BC2_hP5_164_d_a_d-001

Picture of Structure; Click for Big Picture
Prototype H$_{2}$MgO$_{2}$
AFLOW prototype label A2BC2_hP5_164_d_a_d-001
Mineral name brucite
ICSD 79031
Pearson symbol hP5
Space group number 164
Space group symbol $P\overline{3}m1$
AFLOW prototype command aflow --proto=A2BC2_hP5_164_d_a_d-001
--params=$a, \allowbreak c/a, \allowbreak z_{2}, \allowbreak z_{3}$

Other compounds with this structure

Ca(OH)$_{2}$ (Portlandite),  Fe(OH)$_{2}$,  Mn(OH)$_{2}$ (Pyrochroite),  Ni(OH)$_{2}$ (Theophrastite),  $\beta$-Co(OH)$_{2}$


  • We used the data from (Catti, 1995) at ambient pressure. In some Brucite-like materials the hydrogen atoms are displaced to the (6i) Wyckoff positions $(x,-x,z)$ of space group $P3m1$ #164, and these sites are 1/3 occupied.

\[ \begin{array}{ccc} \mathbf{a_{1}}&=&\frac{1}{2}a \,\mathbf{\hat{x}}- \frac{\sqrt{3}}{2}a \,\mathbf{\hat{y}}\\\mathbf{a_{2}}&=&\frac{1}{2}a \,\mathbf{\hat{x}}+\frac{\sqrt{3}}{2}a \,\mathbf{\hat{y}}\\\mathbf{a_{3}}&=&c \,\mathbf{\hat{z}} \end{array}\]

Basis vectors

Lattice coordinates Cartesian coordinates Wyckoff position Atom type
$\mathbf{B_{1}}$ = $0$ = $0$ (1a) Mg I
$\mathbf{B_{2}}$ = $\frac{1}{3} \, \mathbf{a}_{1}+\frac{2}{3} \, \mathbf{a}_{2}+z_{2} \, \mathbf{a}_{3}$ = $\frac{1}{2}a \,\mathbf{\hat{x}}+\frac{\sqrt{3}}{6}a \,\mathbf{\hat{y}}+c z_{2} \,\mathbf{\hat{z}}$ (2d) H I
$\mathbf{B_{3}}$ = $\frac{2}{3} \, \mathbf{a}_{1}+\frac{1}{3} \, \mathbf{a}_{2}- z_{2} \, \mathbf{a}_{3}$ = $\frac{1}{2}a \,\mathbf{\hat{x}}- \frac{\sqrt{3}}{6}a \,\mathbf{\hat{y}}- c z_{2} \,\mathbf{\hat{z}}$ (2d) H I
$\mathbf{B_{4}}$ = $\frac{1}{3} \, \mathbf{a}_{1}+\frac{2}{3} \, \mathbf{a}_{2}+z_{3} \, \mathbf{a}_{3}$ = $\frac{1}{2}a \,\mathbf{\hat{x}}+\frac{\sqrt{3}}{6}a \,\mathbf{\hat{y}}+c z_{3} \,\mathbf{\hat{z}}$ (2d) O I
$\mathbf{B_{5}}$ = $\frac{2}{3} \, \mathbf{a}_{1}+\frac{1}{3} \, \mathbf{a}_{2}- z_{3} \, \mathbf{a}_{3}$ = $\frac{1}{2}a \,\mathbf{\hat{x}}- \frac{\sqrt{3}}{6}a \,\mathbf{\hat{y}}- c z_{3} \,\mathbf{\hat{z}}$ (2d) O I

References

  • M. Catti, G. Ferraris, S. Hull, and A. Pavese, Static compression and H disorder in brucite, Mg(OH)$_{2}$, to 11 GPa: a powder neutron diffraction study, Phys. Chem. Min. 22, 200–206 (1995), doi:10.1007/BF00202300.

Prototype Generator

aflow --proto=A2BC2_hP5_164_d_a_d --params=$a,c/a,z_{2},z_{3}$

Species:

Running:

Output: