Materials Data on Er2Cu(B2O5)2 by Materials Project
Er2Cu(B2O5)2 is Esseneite-like structured and crystallizes in the monoclinic P2_1/c space group. The structure is three-dimensional. Er3+ is bonded in a 8-coordinate geometry to eight O2- atoms. There are a spread of Er–O bond distances ranging from 2.20–2.61 Å. Cu2+ is bonded to six O2- atoms to form distorted CuO6 octahedra that share corners with six BO4 tetrahedra and edges with two equivalent BO4 tetrahedra. There are a spread of Cu–O bond distances ranging from 1.96–2.35 Å. There are two inequivalent B3+ sites. In the first B3+ site, B3+ is bonded to four O2- atoms to form BO4 tetrahedra that share corners with two equivalent CuO6 octahedra and corners with three equivalent BO4 tetrahedra. The corner-sharing octahedra tilt angles range from 67–70°. There are a spread of B–O bond distances ranging from 1.42–1.56 Å. In the second B3+ site, B3+ is bonded to four O2- atoms to form BO4 tetrahedra that share a cornercorner with one CuO6 octahedra, corners with three equivalent BO4 tetrahedra, and an edgeedge with one CuO6 octahedra. The corner-sharing octahedral tilt angles are 60°. There are a spread of B–O bond distances ranging from 1.44–1.53 Å. There are five inequivalent O2- sites. In the first O2- site, O2- is bonded in a distorted bent 120 degrees geometry to one Er3+, one Cu2+, and two B3+ atoms. In the second O2- site, O2- is bonded in a distorted bent 120 degrees geometry to two equivalent Er3+ and two B3+ atoms. In the third O2- site, O2- is bonded in a 4-coordinate geometry to one Er3+, one Cu2+, and two B3+ atoms. In the fourth O2- site, O2- is bonded in a 4-coordinate geometry to two equivalent Er3+, one Cu2+, and one B3+ atom. In the fifth O2- site, O2- is bonded in a 1-coordinate geometry to two equivalent Er3+ and one B3+ atom.