Encyclopedia of Crystallographic Prototypes

AFLOW Prototype: A_hP6_178_a-001

This structure originally had the label A_hP6_178_a. Calls to that address will be redirected here.

If you are using this page, please cite:
D. Hicks, M. J. Mehl, E. Gossett, C. Toher, O. Levy, R. M. Hanson, G. L. W. Hart, and S. Curtarolo, The AFLOW Library of Crystallographic Prototypes: Part 2, Comp. Mat. Sci. 161, S1-S1011 (2019). (doi=10.1016/j.commatsci.2018.10.043)

Links to this page

https://aflow.org/p/Z993
or https://aflow.org/p/A_hP6_178_a-001
or PDF Version

Sc-V (High-Pressure) Structure: A_hP6_178_a-001

Picture of Structure; Click for Big Picture
Prototype Sc
AFLOW prototype label A_hP6_178_a-001
ICSD 153837
Pearson symbol hP6
Space group number 178
Space group symbol $P6_122$
AFLOW prototype command aflow --proto=A_hP6_178_a-001
--params=$a, \allowbreak c/a, \allowbreak x_{1}$

  • This high pressure phase of scandium becomes stable at 240 GPa. We use the experimental data at 242 GPa and 297K. This chiral structure could also have been presented in the enantiomorphic space group $P6_{5}22$ #179.

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

Basis vectors

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

References

  • Y. Akahama, H. Fujihisa, and H. Kawamura, New Helical Chain Structure for Scandium at 240 GPa, Phys. Rev. Lett. 94, 195503 (2005), doi:10.1103/PhysRevLett.94.195503.

Prototype Generator

aflow --proto=A_hP6_178_a --params=$a,c/a,x_{1}$

Species:

Running:

Output: