Materials Data on Tm2MgSe4 by Materials Project

Dataset · Sat May 02 04:00:00 EDT 2020

DOI:https://doi.org/10.17188/1683595· OSTI ID:1683595

MgTm2Se4 crystallizes in the orthorhombic Pnma space group. The structure is three-dimensional. Mg2+ is bonded to five Se2- atoms to form MgSe5 square pyramids that share corners with four TmSe6 octahedra, edges with four TmSe6 octahedra, and edges with four equivalent MgSe5 square pyramids. The corner-sharing octahedra tilt angles range from 5–8°. There are a spread of Mg–Se bond distances ranging from 2.72–2.78 Å. There are two inequivalent Tm3+ sites. In the first Tm3+ site, Tm3+ is bonded to six Se2- atoms to form TmSe6 octahedra that share corners with three equivalent TmSe6 octahedra, corners with two equivalent MgSe5 square pyramids, edges with six TmSe6 octahedra, and an edgeedge with one MgSe5 square pyramid. The corner-sharing octahedra tilt angles range from 53–58°. There are a spread of Tm–Se bond distances ranging from 2.80–2.91 Å. In the second Tm3+ site, Tm3+ is bonded to six Se2- atoms to form TmSe6 octahedra that share corners with three equivalent TmSe6 octahedra, corners with two equivalent MgSe5 square pyramids, edges with four TmSe6 octahedra, and edges with three equivalent MgSe5 square pyramids. The corner-sharing octahedra tilt angles range from 53–58°. There are a spread of Tm–Se bond distances ranging from 2.75–2.90 Å. There are four inequivalent Se2- sites. In the first Se2- site, Se2- is bonded to three equivalent Mg2+ and two equivalent Tm3+ atoms to form a mixture of edge and corner-sharing SeTm2Mg3 square pyramids. In the second Se2- site, Se2- is bonded in a rectangular see-saw-like geometry to four Tm3+ atoms. In the third Se2- site, Se2- is bonded in a distorted T-shaped geometry to three Tm3+ atoms. In the fourth Se2- site, Se2- is bonded to two equivalent Mg2+ and three Tm3+ atoms to form SeTm3Mg2 square pyramids that share corners with two equivalent SeTm2Mg3 square pyramids and edges with five SeTm3Mg2 square pyramids.

• Research Organization: LBNL Materials Project; Lawrence Berkeley National Laboratory (LBNL), Berkeley, CA (United States)
• Sponsoring Organization: USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22)
• Contributing Organization: The Materials Project; MIT; UC Berkeley; Duke; U Louvain
• DOE Contract Number: AC02-05CH11231
• OSTI ID: 1683595
• Report Number(s): mp-1232081
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
Mg-Se-Tm
Tm2MgSe4
crystal structure