$\eta$–Fe2C Structure: AB2_oP6_58_a_g

Picture of Structure; Click for Big Picture
Prototype : $\eta$–Fe2C
AFLOW prototype label : AB2_oP6_58_a_g
Strukturbericht designation : None
Pearson symbol : oP6
Space group number : 58
Space group symbol : $\mbox{Pnnm}$
AFLOW prototype command : aflow --proto=AB2_oP6_58_a_g
--params=
$a$,$b/a$,$c/a$,$x_{2}$,$y_{2}$


  • Classified as bcc-related by Hellner and Schwarz (Westbrook, 1995), Vol. I, Chap. 13. Note that hydrophilite (AB2_oP6_58_a_g, CaCl2), $\eta$–Fe2C (AB2_oP6_58_a_g, $\eta$–Fe2C), and marcasite (AB2_oP6_58_a_g, FeS2) have the same AFLOW prototype label. They are generated by the same symmetry operations with different sets of parameters (––params) specified in their corresponding CIF files.

Simple Orthorhombic primitive vectors:

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

Basis vectors:

\[ \begin{array}{ccccccc} & & \mbox{Lattice Coordinates} & & \mbox{Cartesian Coordinates} &\mbox{Wyckoff Position} & \mbox{Atom Type} \\ \mathbf{B}_{1} & =&0 \, \mathbf{a}_{1} + 0 \, \mathbf{a}_{2} + 0 \, \mathbf{a}_{3} & =&0 \mathbf{\hat{x}} + 0 \mathbf{\hat{y}} + 0 \mathbf{\hat{z}} & \left(2a\right) & \mbox{C} \\ \mathbf{B}_{2} & =&\frac12 \, \mathbf{a}_{1}+ \frac12 \, \mathbf{a}_{2}+ \frac12 \, \mathbf{a}_{3}& =&\frac12 \, a \, \mathbf{\hat{x}}+ \frac12 \, b \, \mathbf{\hat{y}}+ \frac12 \, c \, \mathbf{\hat{z}}& \left(2a\right) & \mbox{C} \\ \mathbf{B}_{3} & =&x_{2} \, \mathbf{a}_{1}+ y_{2} \, \mathbf{a}_{2}& =&x_{2} \, a \, \mathbf{\hat{x}}+ y_{2} \, b \, \mathbf{\hat{y}}& \left(4g\right) & \mbox{Fe} \\ \mathbf{B}_{4} & =&- x_{2} \, \mathbf{a}_{1}- y_{2} \, \mathbf{a}_{2}& =&- x_{2} \, a \, \mathbf{\hat{x}}- y_{2} \, b \, \mathbf{\hat{y}}& \left(4g\right) & \mbox{Fe} \\ \mathbf{B}_{5} & =&\left(\frac12 - x_{2}\right) \, \mathbf{a}_{1}+ \left(\frac12 + y_{2}\right) \, \mathbf{a}_{2}+ \frac12 \, \mathbf{a}_{3}& =&\left(\frac12 - x_{2}\right) \, a \, \mathbf{\hat{x}}+ \left(\frac12 + y_{2}\right) \, b \, \mathbf{\hat{y}}+ \frac12 \, c \, \mathbf{\hat{z}}& \left(4g\right) & \mbox{Fe} \\ \mathbf{B}_{6} & =&\left(\frac12 + x_{2}\right) \, \mathbf{a}_{1}+ \left(\frac12 - y_{2}\right) \, \mathbf{a}_{2}+ \frac12 \, \mathbf{a}_{3}& =&\left(\frac12 + x_{2}\right) \, a \, \mathbf{\hat{x}}+ \left(\frac12 - y_{2}\right) \, b \, \mathbf{\hat{y}}+ \frac12 \, c \, \mathbf{\hat{z}}& \left(4g\right) & \mbox{Fe} \\ \end{array} \]

References

  • Y. Hirotsu and S. Nagakura, Crystal structure and morphology of the carbide precipitated from martensitic high carbon steel during the first stage of tempering, Acta Metallurgica 20, 645–655 (1972), doi:10.1016/0001-6160(72)90020-X.
  • J. H. Westbrook and R. L. Fleischer, Intermetallic Compounds: Principles and Practice (John Wiley & Sons, Chichester, New York, Brisbane, Toronto, Singapore, 1995).

Geometry files


Prototype Generator

aflow --proto=AB2_oP6_58_a_g --params=

Species:

Running:

Output: