Materials Data on KUSi2O7 by Materials Project

Abstract

KUSi2O7 crystallizes in the tetragonal P4/mbm space group. The structure is three-dimensional. K1+ is bonded in a 10-coordinate geometry to twelve O2- atoms. There are a spread of K–O bond distances ranging from 3.04–3.40 Å. U5+ is bonded to six O2- atoms to form UO6 octahedra that share corners with two equivalent UO6 octahedra and corners with four equivalent SiO4 tetrahedra. The corner-sharing octahedral tilt angles are 0°. There are two shorter (2.09 Å) and four longer (2.19 Å) U–O bond lengths. Si4+ is bonded to four O2- atoms to form SiO4 tetrahedra that share corners with two equivalent UO6 octahedra and corners with two equivalent SiO4 tetrahedra. The corner-sharing octahedral tilt angles are 26°. There is three shorter (1.63 Å) and one longer (1.66 Å) Si–O bond length. There are five inequivalent O2- sites. In the first O2- site, O2- is bonded in a linear geometry to four equivalent K1+ and two equivalent U5+ atoms. In the second O2- site, O2- is bonded in a linear geometry to two equivalent Si4+ atoms. In the third O2- site, O2- is bonded in a distorted bent 150 degrees geometry to two equivalent K1+, one U5+, and one Si4+ atom. In the fourth O2- site, O2- is bonded in a linear geometry to two equivalent U5+ atoms. In the fifth O2- site, O2- is bonded in a distorted bent 150 degrees geometry to two equivalent K1+ and two equivalent Si4+ atoms.