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Materials Data on Pr2USe4 by Materials Project

UPr2Se4 crystallizes in the tetragonal I-42d space group. The structure is three-dimensional. U is bonded to eight equivalent Se atoms to form distorted USe8 hexagonal bipyramids that share corners with eight equivalent PrSe8 hexagonal bipyramids, edges with four equivalent USe8 hexagonal bipyramids, and faces with eight equivalent PrSe8 hexagonal bipyramids. There are four shorter (2.99 Å) and four longer (3.12 Å) U–Se bond lengths. Pr is bonded to eight equivalent Se atoms to form distorted PrSe8 hexagonal bipyramids that share corners with four equivalent USe8 hexagonal bipyramids, corners with four equivalent PrSe8 hexagonal bipyramids, edges with four equivalent PrSe8 hexagonal bipyramids, faces with four equivalent USe8 hexagonal bipyramids, and faces with four equivalent PrSe8 hexagonal bipyramids. There are a spread of Pr–Se bond distances ranging from 3.02–3.19 Å. Se is bonded to two equivalent U and four equivalent Pr atoms to form a mixture of distorted edge, face, and corner-sharing SePr4U2 octahedra. The corner-sharing octahedra tilt angles range from 15–50°.

36 MATERIALS SCIENCE↗

Materials Data on Pr2USe5 by Materials Project

UPr2Se5 crystallizes in the orthorhombic Pnma space group. The structure is three-dimensional. U4+ is bonded to seven Se2- atoms to form distorted edge-sharing USe7 pentagonal bipyramids. There are a spread of U–Se bond distances ranging from 2.80–3.02 Å. Pr3+ is bonded in a 8-coordinate geometry to eight Se2- atoms. There are a spread of Pr–Se bond distances ranging from 3.06–3.21 Å. There are four inequivalent Se2- sites. In the first Se2- site, Se2- is bonded in a distorted rectangular see-saw-like geometry to two equivalent U4+ and two equivalent Pr3+ atoms. In the second Se2- site, Se2- is bonded to one U4+ and four equivalent Pr3+ atoms to form a mixture of distorted edge and corner-sharing SePr4U trigonal bipyramids. In the third Se2- site, Se2- is bonded to one U4+ and four equivalent Pr3+ atoms to form a mixture of edge, face, and corner-sharing SePr4U square pyramids. In the fourth Se2- site, Se2- is bonded to one U4+ and four equivalent Pr3+ atoms to form a mixture of distorted edge, face, and corner-sharing SePr4U square pyramids.

36 MATERIALS SCIENCE↗