Materials Data on Sr2TbCu2(BiO4)2 by Materials Project
Sr2TbCu2(BiO4)2 crystallizes in the tetragonal I4/mmm space group. The structure is three-dimensional. Sr2+ is bonded in a 9-coordinate geometry to nine O2- atoms. There are one shorter (2.69 Å) and eight longer (2.76 Å) Sr–O bond lengths. Tb3+ is bonded in a body-centered cubic geometry to eight equivalent O2- atoms. All Tb–O bond lengths are 2.42 Å. Cu+1.50+ is bonded to five O2- atoms to form CuO5 square pyramids that share a cornercorner with one BiO6 octahedra and corners with four equivalent CuO5 square pyramids. The corner-sharing octahedral tilt angles are 0°. There are four shorter (1.90 Å) and one longer (2.51 Å) Cu–O bond lengths. Bi3+ is bonded to six O2- atoms to form BiO6 octahedra that share corners with four equivalent BiO6 octahedra, a cornercorner with one CuO5 square pyramid, and edges with eight equivalent BiO6 octahedra. The corner-sharing octahedral tilt angles are 3°. There are a spread of Bi–O bond distances ranging from 2.13–2.87 Å. There are three inequivalent O2- sites. In the first O2- site, O2- is bonded to two equivalent Sr2+, two equivalent Tb3+, and two equivalent Cu+1.50+ atoms to form distorted OSr2Tb2Cu2 octahedra that share corners with fourteen OSrBi5 octahedra, edges with three equivalent OSr2Tb2Cu2 octahedra, and faces with six OSr4CuBi octahedra. The corner-sharing octahedra tilt angles range from 0–67°. In the second O2- site, O2- is bonded to one Sr2+ and five equivalent Bi3+ atoms to form a mixture of edge and corner-sharing OSrBi5 octahedra. The corner-sharing octahedra tilt angles range from 0–44°. In the third O2- site, O2- is bonded to four equivalent Sr2+, one Cu+1.50+, and one Bi3+ atom to form distorted OSr4CuBi octahedra that share corners with thirteen OSrBi5 octahedra, edges with eight OSrBi5 octahedra, and faces with four equivalent OSr2Tb2Cu2 octahedra. The corner-sharing octahedra tilt angles range from 0–50°.