$\gamma$–Pu Structure: A_oF8_70_a

Picture of Structure; Click for Big Picture
Prototype : $\gamma$–Pu
AFLOW prototype label : A_oF8_70_a
Strukturbericht designation : None
Pearson symbol : oF8
Space group number : 70
Space group symbol : $\mbox{Fddd}$
AFLOW prototype command : aflow --proto=A_oF8_70_a
--params=
$a$,$b/a$,$c/a$


  • 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.

Face-centered Orthorhombic primitive vectors:

\[ \begin{array}{ccc} \mathbf{a}_1 & = & \frac12 \, b \, \mathbf{\hat{y}} + \frac12 \, c \, \mathbf{\hat{z}} \\ \mathbf{a}_2 & = & \frac12 \, a \, \mathbf{\hat{x}} + \frac12 \, c \, \mathbf{\hat{z}} \\ \mathbf{a}_3 & = & \frac12 \, a \, \mathbf{\hat{x}} + \frac12 \, b \, \mathbf{\hat{y}} \\ \end{array} \]

Basis vectors:

\[ \begin{array}{ccccccc} & & \mbox{Lattice Coordinates} & & \mbox{Cartesian Coordinates} &\mbox{Wyckoff Position} & \mbox{Atom Type} \\ \mathbf{B}_{1} & =& \frac18 \, \mathbf{a}_{1} + \frac18 \, \mathbf{a}_{2} + \frac18 \, \mathbf{a}_{3}& =& \frac18 \, a \, \mathbf{\hat{x}} + \frac18 \, b \, \mathbf{\hat{y}} + \frac18 \, c \, \mathbf{\hat{z}}& \left(8a\right) & \mbox{Pu} \\ \mathbf{B}_{2} & =& \frac78 \, \mathbf{a}_{1} + \frac78 \, \mathbf{a}_{2} + \frac78 \, \mathbf{a}_{3}& =& \frac78 \, a \, \mathbf{\hat{x}} + \frac78 \, b \, \mathbf{\hat{y}} + \frac78 \, c \, \mathbf{\hat{z}}& \left(8a\right) & \mbox{Pu} \\ \end{array} \]

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 gamma–plutonium, Acta Cryst. 8, 431–433 (1955), doi:10.1107/S0365110X55001357.
  • J. Donohue, The Structure of the Elements (Robert E. Krieger Publishing Company, Malabar, Florida, 1982).

Geometry files


Prototype Generator

aflow --proto=A_oF8_70_a --params=

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