DOE OSTI2020
ZrSe crystallizes in the triclinic P1 space group. The structure is three-dimensional. there are sixteen inequivalent Zr2+ sites. In the first Zr2+ site, Zr2+ is bonded in a square co-planar geometry to four Se2- atoms. There are a spread of Zr–Se bond distances ranging from 2.68–2.75 Å. In the second Zr2+ site, Zr2+ is bonded to five Se2- atoms to form distorted corner-sharing ZrSe5 trigonal bipyramids. There are a spread of Zr–Se bond distances ranging from 2.74–2.88 Å. In the third Zr2+ site, Zr2+ is bonded in a 6-coordinate geometry to six Se2- atoms. There are a spread of Zr–Se bond distances ranging from 2.70–3.12 Å. In the fourth Zr2+ site, Zr2+ is bonded in a rectangular see-saw-like geometry to four Se2- atoms. There are a spread of Zr–Se bond distances ranging from 2.66–2.76 Å. In the fifth Zr2+ site, Zr2+ is bonded in a square co-planar geometry to four Se2- atoms. There are a spread of Zr–Se bond distances ranging from 2.62–2.74 Å. In the sixth Zr2+ site, Zr2+ is bonded in a rectangular see-saw-like geometry to four Se2- atoms. There are a spread of Zr–Se bond distances ranging from 2.61–2.64 Å. In the seventh Zr2+ site, Zr2+ is bonded in a distorted square co-planar geometry to four Se2- atoms. There are a spread of Zr–Se bond distances ranging from 2.62–2.75 Å. In the eighth Zr2+ site, Zr2+ is bonded to six Se2- atoms to form corner-sharing ZrSe6 octahedra. The corner-sharing octahedra tilt angles range from 14–31°. There are a spread of Zr–Se bond distances ranging from 2.62–2.85 Å. In the ninth Zr2+ site, Zr2+ is bonded in a 6-coordinate geometry to six Se2- atoms. There are a spread of Zr–Se bond distances ranging from 2.73–3.05 Å. In the tenth Zr2+ site, Zr2+ is bonded in a 6-coordinate geometry to six Se2- atoms. There are a spread of Zr–Se bond distances ranging from 2.76–3.21 Å. In the eleventh Zr2+ site, Zr2+ is bonded to six Se2- atoms to form distorted ZrSe6 pentagonal pyramids that share corners with four equivalent ZrSe6 pentagonal pyramids, edges with two equivalent ZrSe6 octahedra, and edges with six ZrSe5 square pyramids. There are a spread of Zr–Se bond distances ranging from 2.72–3.07 Å. In the twelfth Zr2+ site, Zr2+ is bonded in a 6-coordinate geometry to six Se2- atoms. There are a spread of Zr–Se bond distances ranging from 2.65–3.05 Å. In the thirteenth Zr2+ site, Zr2+ is bonded to six Se2- atoms to form distorted ZrSe6 octahedra that share corners with four equivalent ZrSe6 octahedra, edges with two equivalent ZrSe6 pentagonal pyramids, and edges with six ZrSe5 square pyramids. The corner-sharing octahedra tilt angles range from 16–26°. There are a spread of Zr–Se bond distances ranging from 2.66–2.82 Å. In the fourteenth Zr2+ site, Zr2+ is bonded in a 6-coordinate geometry to six Se2- atoms. There are a spread of Zr–Se bond distances ranging from 2.73–3.05 Å. In the fifteenth Zr2+ site, Zr2+ is bonded to five Se2- atoms to form ZrSe5 square pyramids that share corners with four equivalent ZrSe5 square pyramids, edges with four equivalent ZrSe6 octahedra, edges with two equivalent ZrSe6 pentagonal pyramids, and edges with two equivalent ZrSe5 square pyramids. There are a spread of Zr–Se bond distances ranging from 2.68–2.86 Å. In the sixteenth Zr2+ site, Zr2+ is bonded to five Se2- atoms to form ZrSe5 square pyramids that share corners with four equivalent ZrSe5 square pyramids, edges with two equivalent ZrSe6 octahedra, edges with four equivalent ZrSe6 pentagonal pyramids, and edges with two equivalent ZrSe5 square pyramids. There are a spread of Zr–Se bond distances ranging from 2.68–2.78 Å. There are sixteen inequivalent Se2- sites. In the first Se2- site, Se2- is bonded in a 6-coordinate geometry to six Zr2+ atoms. In the second Se2- site, Se2- is bonded in a square co-planar geometry to four Zr2+ atoms. In the third Se2- site, Se2- is bonded in a rectangular see-saw-like geometry to four Zr2+ atoms. In the fourth Se2- site, Se2- is bonded in a rectangular see-saw-like geometry to four Zr2+ atoms. In the fifth Se2- site, Se2- is bonded to six Zr2+ atoms to form distorted corner-sharing SeZr6 pentagonal pyramids. In the sixth Se2- site, Se2- is bonded in a distorted square co-planar geometry to four Zr2+ atoms. In the seventh Se2- site, Se2- is bonded to six Zr2+ atoms to form distorted SeZr6 pentagonal pyramids that share corners with five SeZr6 pentagonal pyramids and edges with four equivalent SeZr5 square pyramids. In the eighth Se2- site, Se2- is bonded in a 6-coordinate geometry to six Zr2+ atoms. In the ninth Se2- site, Se2- is bonded in a 6-coordinate geometry to six Zr2+ atoms. In the tenth Se2- site, Se2- is bonded to six Zr2+ atoms to form distorted SeZr6 octahedra that share corners with four equivalent SeZr6 octahedra, edges with four equivalent SeZr6 octahedra, and edges with two equivalent SeZr5 square pyramids. The corner-sharing octahedra tilt angles range from 16–33°. In the eleventh Se2- site, Se2- is bonded in a 6-coordinate geometry to six Zr2+ atoms. In the twelfth Se2- site, Se2- is bonded in a 4-coordinate geometry to four Zr2+ atoms. In the thirteenth Se2- site, Se2- is bonded to five Zr2+ atoms to form distorted SeZr5 square pyramids that share corners with four equivalent SeZr5 square pyramids and edges with four equivalent SeZr6 pentagonal pyramids. In the fourteenth Se2- site, Se2- is bonded in a 5-coordinate geometry to five Zr2+ atoms. In the fifteenth Se2- site, Se2- is bonded to six Zr2+ atoms to form distorted SeZr6 octahedra that share corners with four equivalent SeZr6 octahedra, edges with four equivalent SeZr6 octahedra, and edges with two equivalent SeZr5 square pyramids. The corner-sharing octahedra tilt angles range from 25–27°. In the sixteenth Se2- site, Se2- is bonded to five Zr2+ atoms to form distorted SeZr5 square pyramids that share corners with four equivalent SeZr5 square pyramids and edges with four SeZr6 octahedra.