$\beta$–Np ($A_{d}$) Structure: A_tP4_129_ac

Picture of Structure; Click for Big Picture
Prototype : $\beta$–Np
AFLOW prototype label : A_tP4_129_ac
Strukturbericht designation : $A_{d}$
Pearson symbol : tP4
Space group number : 129
Space group symbol : $\mbox{P4/nmm}$
AFLOW prototype command : aflow --proto=A_tP4_129_ac
--params=
$a$,$c/a$,$z_{2}$


  • When $z=1/2$ the atoms in this structure are in the L10 (CuAu) or the A6 (indium) structure. This structure is identical to the B10 (PbO) structure. Pearson's Handbook, along with the original papers, give the space group as P421. However, as noted by Structure Reports 15, 121 (1951), the correct space group is P4/nmm. P421 is a subgroup of P4/nmm.

Simple Tetragonal primitive vectors:

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

Basis vectors:

\[ \begin{array}{ccccccc} & & \mbox{Lattice Coordinates} & & \mbox{Cartesian Coordinates} &\mbox{Wyckoff Position} & \mbox{Atom Type} \\ \mathbf{B}_{1} & =&\frac34 \, \mathbf{a}_{1}+ \frac14 \, \mathbf{a}_{2}& =&\frac34 \, a \, \mathbf{\hat{x}}+ \frac14 \, a \, \mathbf{\hat{y}}& \left(2a\right) & \mbox{Np I} \\ \mathbf{B}_{2} & =&\frac14 \, \mathbf{a}_{1}+ \frac34 \, \mathbf{a}_{2}& =&\frac14 \, a \, \mathbf{\hat{x}}+ \frac34 \, a \, \mathbf{\hat{y}}& \left(2a\right) & \mbox{Np I} \\ \mathbf{B}_{3} & =&\frac14 \, \mathbf{a}_{1}+ \frac14 \, \mathbf{a}_{2}+ z_{2} \, \mathbf{a}_{3}& =&\frac14 \, a \, \mathbf{\hat{x}}+ \frac14 \, a \, \mathbf{\hat{y}}+ z_{2} \, c \, \mathbf{\hat{z}}& \left(2c\right) & \mbox{Np II} \\ \mathbf{B}_{4} & =&\frac34 \, \mathbf{a}_{1}+ \frac34 \, \mathbf{a}_{2}- z_{2} \, \mathbf{a}_{3}& =&\frac34 \, a \, \mathbf{\hat{x}}+ \frac34 \, a \, \mathbf{\hat{y}}- z_{2} \, c \, \mathbf{\hat{z}}& \left(2c\right) & \mbox{Np II} \\ \end{array} \]

References

  • W. H. Zachariasen, Crystal chemical studies of the 5f–series of elements. XVIII. Crystal structure studies of neptunium metal at elevated temperatures, Acta Cryst. 5, 664–667 (1952), doi:10.1107/S0365110X52001805.
  • W. B. Pearson, The Crystal Chemistry and Physics of Metals and Alloys (Wiley– Interscience, New York, London, Sydney, Toronto, 1972).
  • A. J. C. Wilson, Structure Reports Vol. 15: Structure Reports for 1951 (N.V.A. Oosthoek's Uitgevers, Utrecht, 1958).

Found in

  • J. Donohue, The Structure of the Elements (Robert E. Krieger Publishing Company, Malabar, Florida, 1982)., pp. 154-156.

Geometry files


Prototype Generator

aflow --proto=A_tP4_129_ac --params=

Species:

Running:

Output: