Materials Data on K2Al2Sb2O7 by Materials Project
K2Al2Sb2O7 crystallizes in the trigonal P-3m1 space group. The structure is three-dimensional. K1+ is bonded in a 9-coordinate geometry to nine equivalent O2- atoms. There are three shorter (2.97 Å) and six longer (3.02 Å) K–O bond lengths. Al3+ is bonded to four O2- atoms to form corner-sharing AlO4 tetrahedra. There is one shorter (1.73 Å) and three longer (1.79 Å) Al–O bond length. Sb3+ is bonded in a distorted T-shaped geometry to three equivalent O2- atoms. All Sb–O bond lengths are 1.97 Å. There are two inequivalent O2- sites. In the first O2- site, O2- is bonded in a 2-coordinate geometry to three equivalent K1+, one Al3+, and one Sb3+ atom. In the second O2- site, O2- is bonded in a linear geometry to two equivalent Al3+ atoms.
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