DOE OSTI2020
Yb29Se32 crystallizes in the tetragonal I4/mmm space group. The structure is three-dimensional. there are seven inequivalent Yb+2.21+ sites. In the first Yb+2.21+ site, Yb+2.21+ is bonded to six Se2- atoms to form a mixture of edge and corner-sharing YbSe6 octahedra. The corner-sharing octahedra tilt angles range from 1–3°. There are a spread of Yb–Se bond distances ranging from 2.92–2.98 Å. In the second Yb+2.21+ site, Yb+2.21+ is bonded to six Se2- atoms to form a mixture of edge and corner-sharing YbSe6 octahedra. The corner-sharing octahedra tilt angles range from 1–2°. There are four shorter (2.95 Å) and two longer (2.96 Å) Yb–Se bond lengths. In the third Yb+2.21+ site, Yb+2.21+ is bonded to six Se2- atoms to form a mixture of edge and corner-sharing YbSe6 octahedra. The corner-sharing octahedra tilt angles range from 1–3°. There are a spread of Yb–Se bond distances ranging from 2.92–2.98 Å. In the fourth Yb+2.21+ site, Yb+2.21+ is bonded to six Se2- atoms to form a mixture of edge and corner-sharing YbSe6 octahedra. The corner-sharing octahedra tilt angles range from 1–2°. All Yb–Se bond lengths are 2.95 Å. In the fifth Yb+2.21+ site, Yb+2.21+ is bonded to six Se2- atoms to form a mixture of edge and corner-sharing YbSe6 octahedra. The corner-sharing octahedral tilt angles are 0°. There are a spread of Yb–Se bond distances ranging from 2.89–2.97 Å. In the sixth Yb+2.21+ site, Yb+2.21+ is bonded to six Se2- atoms to form a mixture of edge and corner-sharing YbSe6 octahedra. The corner-sharing octahedral tilt angles are 0°. There are a spread of Yb–Se bond distances ranging from 2.90–2.95 Å. In the seventh Yb+2.21+ site, Yb+2.21+ is bonded to six Se2- atoms to form a mixture of edge and corner-sharing YbSe6 octahedra. The corner-sharing octahedral tilt angles are 0°. There are four shorter (2.93 Å) and two longer (2.94 Å) Yb–Se bond lengths. There are seven inequivalent Se2- sites. In the first Se2- site, Se2- is bonded to six Yb+2.21+ atoms to form SeYb6 octahedra that share corners with two equivalent SeYb6 octahedra, corners with four SeYb5 square pyramids, edges with eight SeYb6 octahedra, and edges with four SeYb5 square pyramids. The corner-sharing octahedral tilt angles are 0°. In the second Se2- site, Se2- is bonded to five Yb+2.21+ atoms to form SeYb5 square pyramids that share a cornercorner with one SeYb6 octahedra, corners with eight SeYb5 square pyramids, edges with five SeYb6 octahedra, and edges with three SeYb5 square pyramids. The corner-sharing octahedral tilt angles are 2°. In the third Se2- site, Se2- is bonded to five Yb+2.21+ atoms to form SeYb5 square pyramids that share corners with two equivalent SeYb6 octahedra, corners with seven SeYb5 square pyramids, edges with six SeYb6 octahedra, and edges with two equivalent SeYb5 square pyramids. The corner-sharing octahedral tilt angles are 3°. In the fourth Se2- site, Se2- is bonded to five Yb+2.21+ atoms to form SeYb5 square pyramids that share corners with two equivalent SeYb6 octahedra, corners with seven SeYb5 square pyramids, edges with six SeYb6 octahedra, and edges with two equivalent SeYb5 square pyramids. The corner-sharing octahedral tilt angles are 2°. In the fifth Se2- site, Se2- is bonded to five Yb+2.21+ atoms to form SeYb5 square pyramids that share a cornercorner with one SeYb6 octahedra, corners with eight SeYb5 square pyramids, edges with four equivalent SeYb6 octahedra, and edges with four equivalent SeYb5 square pyramids. The corner-sharing octahedral tilt angles are 0°. In the sixth Se2- site, Se2- is bonded to six Yb+2.21+ atoms to form SeYb6 octahedra that share a cornercorner with one SeYb6 octahedra, corners with five SeYb5 square pyramids, edges with eight SeYb6 octahedra, and edges with four equivalent SeYb5 square pyramids. The corner-sharing octahedral tilt angles are 0°. In the seventh Se2- site, Se2- is bonded to six Yb+2.21+ atoms to form SeYb6 octahedra that share corners with six equivalent SeYb6 octahedra, edges with three SeYb6 octahedra, and edges with nine SeYb5 square pyramids. The corner-sharing octahedra tilt angles range from 0–2°.