Encyclopedia of Crystallographic Prototypes

AFLOW Prototype: AB_hP8_194_f_f-003

If you are using this page, please cite:
H. Eckert, S. Divilov, M. J. Mehl, D. Hicks, A. C. Zettel, M. Esters. X. Campilongo and S. Curtarolo, The AFLOW Library of Crystallographic Prototypes: Part 4. Submitted to Computational Materials Science.

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https://aflow.org/p/BDG1
or https://aflow.org/p/AB_hP8_194_f_f-003
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β-GaSe Structure: AB_hP8_194_f_f-003

Prototype	GaSe
AFLOW prototype label	AB_hP8_194_f_f-003
ICSD	41978
Pearson symbol	hP8
Space group number	194
Space group symbol	$P 6_{3} / mm c$
AFLOW prototype command	aflow --proto=AB_hP8_194_f_f-003 --params= $a, c / a, z_{1}, z_{2}$

GaSe takes on a variety of structures depending on the stacking of the Ga $_{2}$ Se $_{2}$ layers:
- $β$ –GaSe (this structure) is in space group $P 6_{3} / mm c$ #194.
- $γ$ –GaSe is in space group $R 3 m$ #160.
- $δ$ –GaSe is in space group $P 6_{3} m c$ #186.
- $ϵ$ –GaSe is in space group $P \overline{6} m 2$ #187.

a_{1} a_{2} a_{3} = = = \frac{1}{2} a \hat{x} - \frac{3}{2} a \hat{y} \frac{1}{2} a \hat{x} + \frac{3}{2} a \hat{y} c \hat{z}

Picture of Structure; Click for Big Picture

Basis vectors

		Lattice coordinates		Cartesian coordinates	Wyckoff position	Atom type
$B_{1}$	=	$\frac{1}{3} a_{1} + \frac{2}{3} a_{2} + z_{1} a_{3}$	=	$\frac{1}{2} a \hat{x} + \frac{3}{6} a \hat{y} + c z_{1} \hat{z}$	(4f)	Ga I
$B_{2}$	=	$\frac{2}{3} a_{1} + \frac{1}{3} a_{2} + (z_{1} + \frac{1}{2}) a_{3}$	=	$\frac{1}{2} a \hat{x} - \frac{3}{6} a \hat{y} + c (z_{1} + \frac{1}{2}) \hat{z}$	(4f)	Ga I
$B_{3}$	=	$\frac{2}{3} a_{1} + \frac{1}{3} a_{2} - z_{1} a_{3}$	=	$\frac{1}{2} a \hat{x} - \frac{3}{6} a \hat{y} - c z_{1} \hat{z}$	(4f)	Ga I
$B_{4}$	=	$\frac{1}{3} a_{1} + \frac{2}{3} a_{2} - (z_{1} - \frac{1}{2}) a_{3}$	=	$\frac{1}{2} a \hat{x} + \frac{3}{6} a \hat{y} - c (z_{1} - \frac{1}{2}) \hat{z}$	(4f)	Ga I
$B_{5}$	=	$\frac{1}{3} a_{1} + \frac{2}{3} a_{2} + z_{2} a_{3}$	=	$\frac{1}{2} a \hat{x} + \frac{3}{6} a \hat{y} + c z_{2} \hat{z}$	(4f)	Se I
$B_{6}$	=	$\frac{2}{3} a_{1} + \frac{1}{3} a_{2} + (z_{2} + \frac{1}{2}) a_{3}$	=	$\frac{1}{2} a \hat{x} - \frac{3}{6} a \hat{y} + c (z_{2} + \frac{1}{2}) \hat{z}$	(4f)	Se I
$B_{7}$	=	$\frac{2}{3} a_{1} + \frac{1}{3} a_{2} - z_{2} a_{3}$	=	$\frac{1}{2} a \hat{x} - \frac{3}{6} a \hat{y} - c z_{2} \hat{z}$	(4f)	Se I
$B_{8}$	=	$\frac{1}{3} a_{1} + \frac{2}{3} a_{2} - (z_{2} - \frac{1}{2}) a_{3}$	=	$\frac{1}{2} a \hat{x} + \frac{3}{6} a \hat{y} - c (z_{2} - \frac{1}{2}) \hat{z}$	(4f)	Se I

References

A. Kuhn, A. Chevy, and R. Chevalier, Crystal Structure and Interatomic Distances in GaSe, phys. stat. sol. (a) 31, 469–475 (1975), doi:10.1002/pssa.2210310216.
K. Schubert, E. Dörre, and M. Kluge, Zur Kristallchemie der B-Metalle. III. Kristallstruktur von GaSe und InTe, Z. Metallkd. 46, 216–224 (1955), doi:10.1515/ijmr-1955-460312.

a

c / a

z_{1}

z_{2}

Encyclopedia of Crystallographic Prototypes

β-GaSe Structure: AB_hP8_194_f_f-003

Hexagonal primitive vectors

References

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