Materials Data on Ca2Th(Si2O5)4 by Materials Project
Ca2Th(Si2O5)4 crystallizes in the tetragonal I422 space group. The structure is three-dimensional. Ca2+ is bonded in a 8-coordinate geometry to eight O2- atoms. There are four shorter (2.35 Å) and four longer (2.73 Å) Ca–O bond lengths. Th4+ is bonded in a 8-coordinate geometry to eight equivalent O2- atoms. All Th–O bond lengths are 2.42 Å. Si4+ is bonded to four O2- atoms to form corner-sharing SiO4 tetrahedra. There are a spread of Si–O bond distances ranging from 1.60–1.66 Å. There are three inequivalent O2- sites. In the first O2- site, O2- is bonded in a 1-coordinate geometry to one Ca2+, one Th4+, and one Si4+ atom. 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 one Ca2+ and two equivalent Si4+ atoms.