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DOE OSTI2020

Materials Data on NdMgSe3 by Materials Project

MgNdSe3 crystallizes in the monoclinic C2/m space group. The structure is three-dimensional. Mg2+ is bonded to six Se+1.67- atoms to form MgSe6 octahedra that share corners with eight equivalent NdSe4 tetrahedra and edges with three equivalent MgSe6 octahedra. There are a spread of Mg–Se bond distances ranging from 2.67–3.03 Å. Nd3+ is bonded to four Se+1.67- atoms to form NdSe4 tetrahedra that share corners with eight equivalent MgSe6 octahedra and an edgeedge with one NdSe4 tetrahedra. The corner-sharing octahedra tilt angles range from 54–76°. There are a spread of Nd–Se bond distances ranging from 2.81–2.83 Å. There are two inequivalent Se+1.67- sites. In the first Se+1.67- site, Se+1.67- is bonded in a distorted trigonal planar geometry to two equivalent Mg2+ and one Nd3+ atom. In the second Se+1.67- site, Se+1.67- is bonded to two equivalent Mg2+ and two equivalent Nd3+ atoms to form edge-sharing SeNd2Mg2 tetrahedra.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Nd2MgSe4 by Materials Project

MgNd2Se4 crystallizes in the tetragonal I-42d space group. The structure is three-dimensional. Mg2+ is bonded in a 4-coordinate geometry to eight equivalent Se2- atoms. There are four shorter (2.76 Å) and four longer (3.38 Å) Mg–Se bond lengths. Nd3+ is bonded in a 8-coordinate geometry to eight equivalent Se2- atoms. There are a spread of Nd–Se bond distances ranging from 2.91–3.33 Å. Se2- is bonded in a 5-coordinate geometry to two equivalent Mg2+ and four equivalent Nd3+ atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Nd2MgSe4 by Materials Project

MgNd2Se4 is Spinel-like structured and crystallizes in the orthorhombic Pnma space group. The structure is three-dimensional. Mg2+ is bonded to four Se2- atoms to form MgSe4 tetrahedra that share corners with six NdSe6 octahedra and edges with three NdSe6 octahedra. The corner-sharing octahedra tilt angles range from 59–64°. There are a spread of Mg–Se bond distances ranging from 2.55–2.62 Å. There are two inequivalent Nd3+ sites. In the first Nd3+ site, Nd3+ is bonded to six Se2- atoms to form NdSe6 octahedra that share corners with four equivalent NdSe6 octahedra, corners with two equivalent MgSe4 tetrahedra, edges with four NdSe6 octahedra, and edges with two equivalent MgSe4 tetrahedra. The corner-sharing octahedra tilt angles range from 51–56°. There are a spread of Nd–Se bond distances ranging from 2.95–3.01 Å. In the second Nd3+ site, Nd3+ is bonded to six Se2- atoms to form NdSe6 octahedra that share corners with eight NdSe6 octahedra, corners with four equivalent MgSe4 tetrahedra, edges with two equivalent NdSe6 octahedra, and an edgeedge with one MgSe4 tetrahedra. The corner-sharing octahedra tilt angles range from 47–56°. There are a spread of Nd–Se bond distances ranging from 2.94–3.02 Å. There are three inequivalent Se2- sites. In the first Se2- site, Se2- is bonded in a rectangular see-saw-like geometry to one Mg2+ and three Nd3+ atoms. In the second Se2- site, Se2- is bonded in a rectangular see-saw-like geometry to one Mg2+ and three Nd3+ atoms. In the third Se2- site, Se2- is bonded to one Mg2+ and three Nd3+ atoms to form distorted corner-sharing SeNd3Mg trigonal pyramids.

36 MATERIALS SCIENCE↗