Mo2B5 ($D8_{i}$) Structure: A5B2_hR7_166_a2c_c

Picture of Structure; Click for Big Picture
Prototype : Mo2B5
AFLOW prototype label : A5B2_hR7_166_a2c_c
Strukturbericht designation : $D8_{i}$
Pearson symbol : hR7
Space group number : 166
Space group symbol : $\mbox{R}\bar{3}\mbox{m}$
AFLOW prototype command : aflow --proto=A5B2_hR7_166_a2c_c [--hex]
--params=
$a$,$c/a$,$x_{2}$,$x_{3}$,$x_{4}$


Other compounds with this structure

  • V2B5, InL5Tl, Li5Sn2, Li5Tl2

  • The boron atoms form buckled graphitic sheets, making this the rhombohedral form of D8h. (Frotscher, 2007) suggest that the stable composition in this part of the molybdenum nitride system might be Mo2B4, but here we will describe the D8i structure, with the warning that this might not be the experimental structure. Hexagonal settings of this structure can be obtained with the option ––hex.

Rhombohedral primitive vectors:

\[ \begin{array}{ccc} \mathbf{a}_1 & = & ~ \frac12 \, a \, \mathbf{\hat{x}} - \frac{1}{2\sqrt{3}} \, a \, \mathbf{\hat{y}} + \frac13 \, c \, \mathbf{\hat{z}} \\ \mathbf{a}_2 & = & \frac{1}{\sqrt{3}} \, a \, \mathbf{\hat{y}} + \frac13 \, c \, \mathbf{\hat{z}} \\ \mathbf{a}_3 & = & - \frac12 \, a \, \mathbf{\hat{x}} - \frac{1}{2\sqrt{3}} \, a \, \mathbf{\hat{y}} + \frac13 \, c \, \mathbf{\hat{z}} \\ \end{array} \]

Basis vectors:

\[ \begin{array}{ccccccc} & & \mbox{Lattice Coordinates} & & \mbox{Cartesian Coordinates} &\mbox{Wyckoff Position} & \mbox{Atom Type} \\ \mathbf{B}_{1} & =&0 \, \mathbf{a}_{1} + 0 \, \mathbf{a}_{2} + 0 \, \mathbf{a}_{3} & =&0 \mathbf{\hat{x}} + 0 \mathbf{\hat{y}} + 0 \mathbf{\hat{z}} & \left(1a\right) & \mbox{B I} \\ \mathbf{B}_{2} & =&x_{2} \, \mathbf{a}_{1}+ x_{2} \, \mathbf{a}_{2}+ x_{2} \, \mathbf{a}_{3}& =&x_{2} \, c \, \mathbf{\hat{z}}& \left(2c\right) & \mbox{B II} \\ \mathbf{B}_{3} & =&- x_{2} \, \mathbf{a}_{1}- x_{2} \, \mathbf{a}_{2}- x_{2} \, \mathbf{a}_{3}& =&- x_{2} \, c \, \mathbf{\hat{z}}& \left(2c\right) & \mbox{B II} \\ \mathbf{B}_{4} & =&x_{3} \, \mathbf{a}_{1}+ x_{3} \, \mathbf{a}_{2}+ x_{3} \, \mathbf{a}_{3}& =&x_{3} \, c \, \mathbf{\hat{z}}& \left(2c\right) & \mbox{B III} \\ \mathbf{B}_{5} & =&- x_{3} \, \mathbf{a}_{1}- x_{3} \, \mathbf{a}_{2}- x_{3} \, \mathbf{a}_{3}& =&- x_{3} \, c \, \mathbf{\hat{z}}& \left(2c\right) & \mbox{B III} \\ \mathbf{B}_{6} & =&x_{4} \, \mathbf{a}_{1}+ x_{4} \, \mathbf{a}_{2}+ x_{4} \, \mathbf{a}_{3}& =&x_{4} \, c \, \mathbf{\hat{z}}& \left(2c\right) & \mbox{Mo} \\ \mathbf{B}_{7} & =&- x_{4} \, \mathbf{a}_{1}- x_{4} \, \mathbf{a}_{2}- x_{4} \, \mathbf{a}_{3}& =&- x_{4} \, c \, \mathbf{\hat{z}}& \left(2c\right) & \mbox{Mo} \\ \end{array} \]

References

  • M. Frotscher, W. Klein, J. Bauer, C. Fang, J. Halet, A. Senyshyn, C. Baehtz, and B. Albert, M2B5 or M2B4? A Reinvestigation of the Mo/B and W/B System, Z. Anorg. Allg. Chem. 633, 2626–2630 (2007), doi:10.1002/zaac.200700376.

Geometry files


Prototype Generator

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