Materials Data on Er2Si2O7 by Materials Project
Er2Si2O7 crystallizes in the monoclinic C2/m space group. The structure is three-dimensional. Er3+ is bonded to six O2- atoms to form distorted ErO6 pentagonal pyramids that share corners with six equivalent SiO4 tetrahedra and edges with three equivalent ErO6 pentagonal pyramids. There are four shorter (2.24 Å) and two longer (2.31 Å) Er–O bond lengths. Si4+ is bonded to four O2- atoms to form SiO4 tetrahedra that share corners with six equivalent ErO6 pentagonal pyramids and a cornercorner with one SiO4 tetrahedra. There is two shorter (1.64 Å) and two longer (1.65 Å) Si–O bond length. There are three inequivalent O2- sites. In the first O2- site, O2- is bonded in a distorted trigonal planar geometry to two equivalent Er3+ 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 trigonal planar geometry to two equivalent Er3+ and one Si4+ atom.