Materials Data on KU2(PO4)3 by Materials Project
KU2(PO4)3 crystallizes in the trigonal R-3c space group. The structure is three-dimensional. K1+ is bonded in a hexagonal planar geometry to six equivalent O2- atoms. All K–O bond lengths are 2.91 Å. U4+ is bonded to six O2- atoms to form UO6 octahedra that share corners with six equivalent PO4 tetrahedra. There are three shorter (2.24 Å) and three longer (2.27 Å) U–O bond lengths. P5+ is bonded to four O2- atoms to form PO4 tetrahedra that share corners with four equivalent UO6 octahedra. The corner-sharing octahedra tilt angles range from 26–31°. All P–O bond lengths are 1.55 Å. There are two inequivalent O2- sites. In the first O2- site, O2- is bonded in a bent 150 degrees geometry to one U4+ and one P5+ atom. In the second O2- site, O2- is bonded in a 2-coordinate geometry to one K1+, one U4+, and one P5+ atom.