DOI: 10.17188/1689173
title: Materials Data on Pr2MgSe4 by Materials Project

description: MgPr2Se4 crystallizes in the orthorhombic Pca2_1 space group. The structure is three-dimensional. there are two inequivalent Mg2+ sites. In the first Mg2+ site, Mg2+ is bonded to six Se2- atoms to form MgSe6 octahedra that share a cornercorner with one PrSe6 octahedra, corners with two equivalent MgSe6 octahedra, corners with four PrSe7 pentagonal bipyramids, an edgeedge with one MgSe6 octahedra, edges with four PrSe6 octahedra, and edges with three PrSe7 pentagonal bipyramids. The corner-sharing octahedra tilt angles range from 11–53°. There are a spread of Mg–Se bond distances ranging from 2.65–3.14 Å. In the second Mg2+ site, Mg2+ is bonded to six Se2- atoms to form MgSe6 octahedra that share a cornercorner with one PrSe6 octahedra, corners with two equivalent MgSe6 octahedra, corners with four PrSe7 pentagonal bipyramids, an edgeedge with one MgSe6 octahedra, edges with four PrSe6 octahedra, and edges with three PrSe7 pentagonal bipyramids. The corner-sharing octahedra tilt angles range from 11–53°. There are a spread of Mg–Se bond distances ranging from 2.66–3.01 Å. There are four inequivalent Pr3+ sites. In the first Pr3+ site, Pr3+ is bonded to six Se2- atoms to form PrSe6 octahedra that share a cornercorner with one MgSe6 octahedra, corners with two equivalent PrSe6 octahedra, corners with four PrSe7 pentagonal bipyramids, an edgeedge with one PrSe6 octahedra, edges with four MgSe6 octahedra, and edges with three PrSe7 pentagonal bipyramids. The corner-sharing octahedra tilt angles range from 11–53°. There are a spread of Pr–Se bond distances ranging from 2.91–3.00 Å. In the second Pr3+ site, Pr3+ is bonded to six Se2- atoms to form PrSe6 octahedra that share a cornercorner with one MgSe6 octahedra, corners with two equivalent PrSe6 octahedra, corners with four PrSe7 pentagonal bipyramids, an edgeedge with one PrSe6 octahedra, edges with four MgSe6 octahedra, and edges with three PrSe7 pentagonal bipyramids. The corner-sharing octahedra tilt angles range from 11–53°. There are a spread of Pr–Se bond distances ranging from 2.91–3.03 Å. In the third Pr3+ site, Pr3+ is bonded to seven Se2- atoms to form distorted PrSe7 pentagonal bipyramids that share corners with four MgSe6 octahedra, corners with four PrSe6 octahedra, edges with three MgSe6 octahedra, edges with three PrSe6 octahedra, and faces with two equivalent PrSe7 pentagonal bipyramids. The corner-sharing octahedra tilt angles range from 13–71°. There are a spread of Pr–Se bond distances ranging from 2.97–3.25 Å. In the fourth Pr3+ site, Pr3+ is bonded to seven Se2- atoms to form distorted PrSe7 pentagonal bipyramids that share corners with four MgSe6 octahedra, corners with four PrSe6 octahedra, edges with three MgSe6 octahedra, edges with three PrSe6 octahedra, and faces with two equivalent PrSe7 pentagonal bipyramids. The corner-sharing octahedra tilt angles range from 16–72°. There are a spread of Pr–Se bond distances ranging from 2.96–3.29 Å. There are eight inequivalent Se2- sites. In the first Se2- site, Se2- is bonded to two Mg2+ and three Pr3+ atoms to form distorted SePr3Mg2 trigonal bipyramids that share corners with two equivalent SePr3Mg2 square pyramids, corners with three equivalent SePr3Mg tetrahedra, corners with two equivalent SePr3Mg2 trigonal bipyramids, edges with five SePr3Mg2 square pyramids, and edges with three SePr3Mg2 trigonal bipyramids. In the second Se2- site, Se2- is bonded to two Mg2+ and three Pr3+ atoms to form distorted SePr3Mg2 trigonal bipyramids that share corners with six SePr3Mg2 square pyramids, corners with two equivalent SePr3Mg tetrahedra, corners with two equivalent SePr3Mg2 trigonal bipyramids, edges with three SePr3Mg2 square pyramids, an edgeedge with one SePr3Mg tetrahedra, and edges with three SePr3Mg2 trigonal bipyramids. In the third Se2- site, Se2- is bonded to one Mg2+ and three Pr3+ atoms to form a mixture of distorted corner and edge-sharing SePr3Mg tetrahedra. In the fourth Se2- site, Se2- is bonded in a distorted rectangular see-saw-like geometry to one Mg2+ and three Pr3+ atoms. In the fifth Se2- site, Se2- is bonded to two Mg2+ and three Pr3+ atoms to form distorted SePr3Mg2 square pyramids that share a cornercorner with one SePr3Mg tetrahedra, corners with eight SePr3Mg2 trigonal bipyramids, edges with four SePr3Mg2 square pyramids, an edgeedge with one SePr3Mg tetrahedra, and edges with two SePr3Mg2 trigonal bipyramids. In the sixth Se2- site, Se2- is bonded to two Mg2+ and three Pr3+ atoms to form SePr3Mg2 square pyramids that share corners with two equivalent SePr4Mg square pyramids, a cornercorner with one SePr3Mg tetrahedra, corners with six SePr3Mg2 trigonal bipyramids, edges with three SePr3Mg2 square pyramids, an edgeedge with one SePr3Mg tetrahedra, and edges with three SePr3Mg2 trigonal bipyramids. In the seventh Se2- site, Se2- is bonded to one Mg2+ and four Pr3+ atoms to form distorted SePr4Mg square pyramids that share corners with two equivalent SePr3Mg2 square pyramids, corners with two equivalent SePr3Mg tetrahedra, corners with two equivalent SePr4Mg trigonal bipyramids, edges with three SePr3Mg2 square pyramids, an edgeedge with one SePr3Mg tetrahedra, and edges with five SePr3Mg2 trigonal bipyramids. In the eighth Se2- site, Se2- is bonded to one Mg2+ and four Pr3+ atoms to form distorted SePr4Mg trigonal bipyramids that share corners with eight SePr3Mg2 square pyramids, corners with three equivalent SePr3Mg tetrahedra, edges with two SePr3Mg2 square pyramids, and edges with four SePr3Mg2 trigonal bipyramids.