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PrS2 is Cubic Laves structured and crystallizes in the cubic Fd-3m space group. The structure is three-dimensional. Pr4+ is bonded in a 12-coordinate geometry to twelve equivalent S2- atoms. All Pr–S bond lengths are 3.30 Å. S2- is bonded to six equivalent Pr4+ and six equivalent S2- atoms to form a mixture of face, edge, and corner-sharing SPr6S6 cuboctahedra. All S–S bond lengths are 2.81 Å.
PrS2 crystallizes in the orthorhombic Pnma space group. The structure is three-dimensional. Pr4+ is bonded in a 9-coordinate geometry to nine S2- atoms. There are a spread of Pr–S bond distances ranging from 2.88–3.21 Å. There are three inequivalent S2- sites. In the first S2- site, S2- is bonded to five equivalent Pr4+ atoms to form a mixture of distorted corner and edge-sharing SPr5 trigonal bipyramids. In the second S2- site, S2- is bonded in a 5-coordinate geometry to four equivalent Pr4+ and one S2- atom. The S–S bond length is 2.12 Å. In the third S2- site, S2- is bonded in a 5-coordinate geometry to four equivalent Pr4+ and one S2- atom.
PrS2 crystallizes in the monoclinic P2_1/c space group. The structure is three-dimensional. Pr4+ is bonded in a 9-coordinate geometry to nine S2- atoms. There are a spread of Pr–S bond distances ranging from 2.87–3.20 Å. There are two inequivalent S2- sites. In the first S2- site, S2- is bonded to five equivalent Pr4+ atoms to form a mixture of distorted corner and edge-sharing SPr5 trigonal bipyramids. In the second S2- site, S2- is bonded in a 5-coordinate geometry to four equivalent Pr4+ and one S2- atom. The S–S bond length is 2.15 Å.
CaPr2S4 crystallizes in the tetragonal I-42d space group. The structure is three-dimensional. Ca2+ is bonded to eight equivalent S2- atoms to form distorted CaS8 hexagonal bipyramids that share corners with eight equivalent PrS8 hexagonal bipyramids, edges with four equivalent CaS8 hexagonal bipyramids, and faces with eight equivalent PrS8 hexagonal bipyramids. There are four shorter (2.88 Å) and four longer (3.11 Å) Ca–S bond lengths. Pr3+ is bonded to eight equivalent S2- atoms to form distorted PrS8 hexagonal bipyramids that share corners with four equivalent CaS8 hexagonal bipyramids, corners with four equivalent PrS8 hexagonal bipyramids, edges with four equivalent PrS8 hexagonal bipyramids, faces with four equivalent CaS8 hexagonal bipyramids, and faces with four equivalent PrS8 hexagonal bipyramids. There are a spread of Pr–S bond distances ranging from 2.89–3.12 Å. S2- is bonded in a 6-coordinate geometry to two equivalent Ca2+ and four equivalent Pr3+ atoms.