Materials Data on Sr(AlSe2)2 by Materials Project
Sr(AlSe2)2 crystallizes in the orthorhombic Cccm space group. The structure is three-dimensional. Sr2+ is bonded in a 8-coordinate geometry to eight Se2- atoms. There are four shorter (3.29 Å) and four longer (3.32 Å) Sr–Se bond lengths. Al3+ is bonded to four Se2- atoms to form edge-sharing AlSe4 tetrahedra. There are a spread of Al–Se bond distances ranging from 2.41–2.44 Å. There are two inequivalent Se2- sites. In the first Se2- site, Se2- is bonded in a 4-coordinate geometry to two equivalent Sr2+ and two equivalent Al3+ atoms. In the second Se2- site, Se2- is bonded to two equivalent Sr2+ and two equivalent Al3+ atoms to form a mixture of distorted edge and corner-sharing SeSr2Al2 trigonal pyramids.
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