Materials Data on MgU2(SiO8)2 by Materials Project

MgU2(SiO8)2 crystallizes in the monoclinic C2/m space group. The structure is three-dimensional. Mg is bonded to six O atoms to form MgO6 octahedra that share corners with two equivalent SiO4 tetrahedra. There are two shorter (1.96 Å) and four longer (2.07 Å) Mg–O bond lengths. U is bonded in a 7-coordinate geometry to seven O atoms. There are a spread of U–O bond distances ranging from 1.81–2.56 Å. Si is bonded to four O atoms to form SiO4 tetrahedra that share a cornercorner with one MgO6 octahedra. The corner-sharing octahedral tilt angles are 20°. There is two shorter (1.63 Å) and two longer (1.65 Å) Si–O bond length. There are six inequivalent O sites. In the first O site, O is bonded in a bent 150 degrees geometry to one U and one Si atom. In the second O site, O is bonded in a bent 150 degrees geometry to one Mg and one Si atom. In the third O site, O is bonded in a 1-coordinate geometry to two equivalent U and one Si atom. In the fourth O site, O is bonded in a single-bond geometry to one U atom. In the fifth O site, O is bonded in a single-bond geometry to one U atom. In the sixth O site, O is bonded in a single-bond geometry to one Mg atom.