Materials Data on Sr2NdGaCu2O7 by Materials Project
GaSr2NdCu2O7 crystallizes in the orthorhombic Ima2 space group. The structure is three-dimensional. Sr2+ is bonded in a 9-coordinate geometry to nine O2- atoms. There are a spread of Sr–O bond distances ranging from 2.48–3.22 Å. Nd3+ is bonded in a body-centered cubic geometry to eight O2- atoms. There are a spread of Nd–O bond distances ranging from 2.47–2.51 Å. Cu2+ is bonded to five O2- atoms to form CuO5 square pyramids that share corners with four equivalent CuO5 square pyramids and a cornercorner with one GaO4 tetrahedra. There are a spread of Cu–O bond distances ranging from 1.96–2.40 Å. Ga3+ is bonded to four O2- atoms to form GaO4 tetrahedra that share corners with two equivalent CuO5 square pyramids and corners with two equivalent GaO4 tetrahedra. There are a spread of Ga–O bond distances ranging from 1.85–1.93 Å. There are four inequivalent O2- sites. In the first O2- site, O2- is bonded in a 1-coordinate geometry to four equivalent Sr2+, one Cu2+, and one Ga3+ atom. In the second O2- site, O2- is bonded to two equivalent Sr2+ and two equivalent Ga3+ atoms to form distorted OSr2Ga2 tetrahedra that share corners with four equivalent OSr2Nd2Cu2 octahedra and corners with two equivalent OSr2Ga2 tetrahedra. The corner-sharing octahedra tilt angles range from 19–47°. In the third O2- site, O2- is bonded in a 6-coordinate geometry to two equivalent Sr2+, two equivalent Nd3+, and two equivalent Cu2+ atoms. In the fourth O2- site, O2- is bonded to two equivalent Sr2+, two equivalent Nd3+, and two equivalent Cu2+ atoms to form distorted OSr2Nd2Cu2 octahedra that share corners with four equivalent OSr2Nd2Cu2 octahedra, corners with two equivalent OSr2Ga2 tetrahedra, and faces with two equivalent OSr2Nd2Cu2 octahedra. The corner-sharing octahedra tilt angles range from 0–67°.