This is the high temperature structure of FeSi$_{2}$. The actual composition is Fe$_{x}$Si$_{2}$ with $x < 1$, and the transition temperature varies with composition between 962 and 1000K. (Villars, 2018) The low temperature structure is body-centered orthorhombic.
$\frac{1}{2}a \,\mathbf{\hat{x}}+\frac{1}{2}a \,\mathbf{\hat{y}}- c z_{2} \,\mathbf{\hat{z}}$
(2h)
Si I
References
B. Aronson, A Note on the Compositions and Crystal Structures of MnB$_2$, Mn$_3$Si, Mn$_5$Si$_3$, and FeSi$_2$, Acta Chem. Scand. 14, 1414–1418 (1960), doi:10.3891/acta.chem.scand.14-1414.
H. Eckert, S. Divilov, M. J. Mehl, D. Hicks, A. C. Zettel, M. Esters, X. Campilongo, and S. Curtarolo, The AFLOW Library of Crystallographic Prototypes: Part 4, Comp. Mat. Sci. 240, 112988 (2024). (doi=10.1016/j.commatsci.2021.110450)