Ca2PrO4 crystallizes in the orthorhombic Pbam space group. Ca(1) is bonded in a 6-coordinate geometry to two equivalent O(2) and four equivalent O(1) atoms. Pr(1) is bonded to two equivalent O(1) and four equivalent O(2) atoms to form edge-sharing PrO6 octahedra. There are two inequivalent O sites. In the first O site, O(1) is bonded to four equivalent Ca(1) and one Pr(1) atom to form OCa4Pr square pyramids that share corners with five equivalent O(1)Ca4Pr square pyramids, corners with eight equivalent O(2)Ca2Pr2 trigonal pyramids, edges with four equivalent O(1)Ca4Pr square pyramids, and edges with two equivalent O(2)Ca2Pr2 trigonal pyramids. In the second O site, O(2) is bonded to two equivalent Ca(1) and two equivalent Pr(1) atoms to form distorted OCa2Pr2 trigonal pyramids that share corners with eight equivalent O(1)Ca4Pr square pyramids, corners with four equivalent O(2)Ca2Pr2 trigonal pyramids, edges with two equivalent O(1)Ca4Pr square pyramids, and edges with two equivalent O(2)Ca2Pr2 trigonal pyramids.
Ca2PrO4 crystallizes in the orthorhombic Pbam space group. Ca(1) is bonded in a 6-coordinate geometry to two equivalent O(2) and four equivalent O(1) atoms. There is one shorter (2.28 Å) and one longer (2.41 Å) Ca(1)-O(2) bond length. There are two shorter (2.49 Å) and two longer (2.50 Å) Ca(1)-O(1) bond lengths. Pr(1) is bonded to two equivalent O(1) and four equivalent O(2) atoms to form edge-sharing PrO6 octahedra. Both Pr(1)-O(1) bond lengths are 2.35 Å. All Pr(1)-O(2) bond lengths are 2.38 Å. There are two inequivalent O sites. In the first O site, O(1) is bonded to four equivalent Ca(1) and one Pr(1) atom to form OCa4Pr square pyramids that share corners with five equivalent O(1)Ca4Pr square pyramids, corners with eight equivalent O(2)Ca2Pr2 trigonal pyramids, edges with four equivalent O(1)Ca4Pr square pyramids, and edges with two equivalent O(2)Ca2Pr2 trigonal pyramids. In the second O site, O(2) is bonded to two equivalent Ca(1) and two equivalent Pr(1) atoms to form distorted OCa2Pr2 trigonal pyramids that share corners with eight equivalent O(1)Ca4Pr square pyramids, corners with four equivalent O(2)Ca2Pr2 trigonal pyramids, edges with two equivalent O(1)Ca4Pr square pyramids, and edges with two equivalent O(2)Ca2Pr2 trigonal pyramids.