DOI: 10.17188/1692484
title: Materials Data on Ca8(YbSe4)3 by Materials Project

description: Ca8(YbSe4)3 crystallizes in the tetragonal P-4m2 space group. The structure is three-dimensional. there are four inequivalent Ca2+ sites. In the first Ca2+ site, Ca2+ is bonded to six Se2- atoms to form CaSe6 octahedra that share corners with five equivalent CaSe6 octahedra, edges with two equivalent YbSe6 octahedra, and edges with ten CaSe6 octahedra. The corner-sharing octahedra tilt angles range from 0–1°. There are five shorter (2.97 Å) and one longer (2.99 Å) Ca–Se bond lengths. In the second Ca2+ site, Ca2+ is bonded to six Se2- atoms to form CaSe6 octahedra that share a cornercorner with one YbSe6 octahedra, corners with five CaSe6 octahedra, and edges with twelve CaSe6 octahedra. The corner-sharing octahedral tilt angles are 0°. There are five shorter (2.97 Å) and one longer (2.98 Å) Ca–Se bond lengths. In the third Ca2+ site, Ca2+ is bonded to six Se2- atoms to form CaSe6 octahedra that share a cornercorner with one YbSe6 octahedra, corners with five CaSe6 octahedra, edges with four CaSe6 octahedra, and edges with six YbSe6 octahedra. The corner-sharing octahedra tilt angles range from 0–1°. There are five shorter (2.97 Å) and one longer (3.00 Å) Ca–Se bond lengths. In the fourth Ca2+ site, Ca2+ is bonded to six Se2- atoms to form CaSe6 octahedra that share a cornercorner with one YbSe6 octahedra, corners with five equivalent CaSe6 octahedra, edges with two equivalent YbSe6 octahedra, and edges with ten CaSe6 octahedra. The corner-sharing octahedra tilt angles range from 0–1°. There are five shorter (2.97 Å) and one longer (2.98 Å) Ca–Se bond lengths. There are two inequivalent Yb+2.67+ sites. In the first Yb+2.67+ site, Yb+2.67+ is bonded to six Se2- atoms to form YbSe6 octahedra that share corners with two CaSe6 octahedra, corners with four equivalent YbSe6 octahedra, edges with two equivalent YbSe6 octahedra, and edges with eight CaSe6 octahedra. The corner-sharing octahedra tilt angles range from 0–1°. There are a spread of Yb–Se bond distances ranging from 2.96–2.99 Å. In the second Yb+2.67+ site, Yb+2.67+ is bonded to six Se2- atoms to form YbSe6 octahedra that share corners with two equivalent CaSe6 octahedra, corners with four equivalent YbSe6 octahedra, edges with four equivalent CaSe6 octahedra, and edges with four equivalent YbSe6 octahedra. The corner-sharing octahedral tilt angles are 0°. There are four shorter (2.97 Å) and two longer (2.98 Å) Yb–Se bond lengths. There are seven inequivalent Se2- sites. In the first Se2- site, Se2- is bonded to three Ca2+ and three Yb+2.67+ atoms to form SeCa3Yb3 octahedra that share corners with six SeCa3Yb3 octahedra, edges with four SeCa6 octahedra, and edges with four equivalent SeCa3Yb2 square pyramids. The corner-sharing octahedra tilt angles range from 0–1°. In the second Se2- site, Se2- is bonded to six Ca2+ atoms to form SeCa6 octahedra that share corners with five SeCa6 octahedra, edges with ten SeCa3Yb3 octahedra, and edges with two equivalent SeCa3Yb2 square pyramids. The corner-sharing octahedra tilt angles range from 0–1°. In the third Se2- site, Se2- is bonded to three Ca2+ and two equivalent Yb+2.67+ atoms to form SeCa3Yb2 square pyramids that share a cornercorner with one SeCa6 octahedra, corners with four equivalent SeCa3Yb2 square pyramids, and edges with eight SeCa3Yb3 octahedra. The corner-sharing octahedral tilt angles are 0°. In the fourth Se2- site, Se2- is bonded to six Ca2+ atoms to form SeCa6 octahedra that share corners with six SeCa3Yb3 octahedra and edges with twelve SeCa6 octahedra. The corner-sharing octahedral tilt angles are 0°. In the fifth Se2- site, Se2- is bonded to five Ca2+ and one Yb+2.67+ atom to form SeCa5Yb octahedra that share corners with five SeCa6 octahedra, edges with ten SeCa3Yb3 octahedra, and edges with two equivalent SeCa3Yb2 square pyramids. The corner-sharing octahedral tilt angles are 0°. In the sixth Se2- site, Se2- is bonded to six Ca2+ atoms to form SeCa6 octahedra that share corners with four equivalent SeCa6 octahedra, corners with two equivalent SeCa3Yb2 square pyramids, and edges with twelve SeCa6 octahedra. The corner-sharing octahedral tilt angles are 0°. In the seventh Se2- site, Se2- is bonded in a square co-planar geometry to one Ca2+ and three Yb+2.67+ atoms.