Materials Data on Eu2SiO5 by Materials Project
Eu2SiO5 crystallizes in the orthorhombic Pnma space group. The structure is three-dimensional. there are two inequivalent Eu3+ sites. In the first Eu3+ site, Eu3+ is bonded in a 7-coordinate geometry to seven O2- atoms. There are a spread of Eu–O bond distances ranging from 2.32–2.73 Å. In the second Eu3+ site, Eu3+ is bonded to seven O2- atoms to form distorted EuO7 hexagonal pyramids that share a cornercorner with one SiO5 trigonal bipyramid, edges with four equivalent EuO7 hexagonal pyramids, and edges with two equivalent SiO5 trigonal bipyramids. There are a spread of Eu–O bond distances ranging from 2.34–2.54 Å. Si4+ is bonded to five O2- atoms to form distorted SiO5 trigonal bipyramids that share a cornercorner with one EuO7 hexagonal pyramid, corners with two equivalent SiO5 trigonal bipyramids, and edges with two equivalent EuO7 hexagonal pyramids. There are a spread of Si–O bond distances ranging from 1.64–1.91 Å. There are five inequivalent O2- sites. In the first O2- site, O2- is bonded to four Eu3+ atoms to form a mixture of edge and corner-sharing OEu4 tetrahedra. In the second O2- site, O2- is bonded in a distorted trigonal planar geometry to two equivalent Eu3+ and one Si4+ atom. In the third O2- site, O2- is bonded to three Eu3+ and one Si4+ atom to form distorted OEu3Si tetrahedra that share corners with eight OEu4 tetrahedra and edges with three OEu3Si tetrahedra. In the fourth O2- site, O2- is bonded in a 2-coordinate geometry to two Eu3+ and two equivalent Si4+ atoms. In the fifth O2- site, O2- is bonded to three Eu3+ and one Si4+ atom to form distorted OEu3Si tetrahedra that share corners with eight OEu4 tetrahedra and edges with two equivalent OEu3Si tetrahedra.