The crystal structure of copper iron selenide, CuFeSe2

Abstract The crystal structure of CuFeSe2 has been found to be tetragonal, space group P 4 2c [D212, N° 112], with a=5.530(1), c=11.049(2)A and Z=4. The structure is a superstructure based upon a cubic close-packed array of anions with the cations occupying a fraction of the available tetrahedral sites. It can be viewed as a sulvanite derivative structure instead of a chalcopyrite-type of structure as expected for a typical I-III-VI2 semiconductor compound. The structure was solved by analyzing the two possible arrangements permitted by the subgroup-supergroup relationships. The refinement, carried out by full-matrix least-squares techniques, led to R(F) = 0.082 and Rw(F)=0.069 using all 310 independent reflections measured with a four-circle single-crystal diffractometer.