γ-Pu Structure: A_oF8_70_a-001
- Plutonium has been found in a variety of structures (Donohue, 1982):
- $\alpha$–Pu
- $\beta$–Pu
- $\gamma$–Pu (this structure)
- $\delta$–Pu is in the face-centered cubic $A1$ structure
- $\delta$'-Pu is in the body-centered tetragonal $A6$ (In) structure
- $\epsilon$–Pu is in the body-centered cubic $A2$ structure
- It is obvious from the coordinates that this is an extremely distorted diamond ($A4$) structure, but, as noted by (Donohue, 1982), it can also be considered as a distorted hcp ($A3$) structure.
\[ \begin{array}{ccc}
\mathbf{a_{1}}&=&\frac{1}{2}b \,\mathbf{\hat{y}}+\frac{1}{2}c \,\mathbf{\hat{z}}\\\mathbf{a_{2}}&=&\frac{1}{2}a \,\mathbf{\hat{x}}+\frac{1}{2}c \,\mathbf{\hat{z}}\\\mathbf{a_{3}}&=&\frac{1}{2}a \,\mathbf{\hat{x}}+\frac{1}{2}b \,\mathbf{\hat{y}}
\end{array}\]
Basis vectors
| Lattice coordinates | Cartesian coordinates | Wyckoff position | Atom type | |||
|---|---|---|---|---|---|---|
| $\mathbf{B_{1}}$ | = | $\frac{1}{8} \, \mathbf{a}_{1}+\frac{1}{8} \, \mathbf{a}_{2}+\frac{1}{8} \, \mathbf{a}_{3}$ | = | $\frac{1}{8}a \,\mathbf{\hat{x}}+\frac{1}{8}b \,\mathbf{\hat{y}}+\frac{1}{8}c \,\mathbf{\hat{z}}$ | (8a) | Pu I |
| $\mathbf{B_{2}}$ | = | $\frac{7}{8} \, \mathbf{a}_{1}+\frac{7}{8} \, \mathbf{a}_{2}+\frac{7}{8} \, \mathbf{a}_{3}$ | = | $\frac{7}{8}a \,\mathbf{\hat{x}}+\frac{7}{8}b \,\mathbf{\hat{y}}+\frac{7}{8}c \,\mathbf{\hat{z}}$ | (8a) | Pu I |
References
- W. H. Zachariasen and F. H. Ellinger, Crystal chemical studies of the 5f-series of elements. XXIV. The crystal structure and thermal expansion of γ-plutonium, Acta Cryst. 8, 431–433 (1955), doi:10.1107/S0365110X55001357.
Found in
- J. Donohue, The Structures of the Elements (Robert E. Krieger Publishing Company, New York, 1974).
First cited in
- M. J. Mehl, D. Hicks, C. Toher, O. Levy, R. M. Hanson, G. L. W. Hart, and S. Curtarolo, The AFLOW Library of Crystallographic Prototypes: Part 1, Comp. Mat. Sci. 136, S1-S828 (2017). (doi=10.1016/j.commatsci.2017.01.017)
Geometry files
Prototype Generator
aflow --proto=A_oF8_70_a --params=$a,b/a,c/a$