Ca3Pr2Sb3O14 crystallizes in the monoclinic C2/m space group. There are three inequivalent Ca sites. In the first Ca site, Ca(1) is bonded to two equivalent O(5) and four equivalent O(4) atoms to form CaO6 octahedra that share corners with two equivalent Sb(1)O6 octahedra and corners with four equivalent Sb(2)O6 octahedra. The corner-sharing octahedral tilt angles range from 57-58°. In the second Ca site, Ca(2) is bonded to two equivalent O(1), two equivalent O(2), and four equivalent O(3) atoms to form CaO8 hexagonal bipyramids that share edges with two equivalent Sb(1)O6 octahedra and edges with four equivalent Sb(2)O6 octahedra. In the third Ca site, Ca(3) is bonded in a distorted body-centered cubic geometry to two equivalent O(1), two equivalent O(2), and four equivalent O(4) atoms. Pr(1) is bonded in a distorted body-centered cubic geometry to two equivalent O(2), two equivalent O(3), two equivalent O(4), and two equivalent O(5) atoms. There are two inequivalent Sb sites. In the first Sb site, Sb(1) is bonded to two equivalent O(5) and four equivalent O(3) atoms to form SbO6 octahedra that share corners with two equivalent Ca(1)O6 octahedra, corners with four equivalent Sb(2)O6 octahedra, and edges with two equivalent Ca(2)O8 hexagonal bipyramids. The corner-sharing octahedral tilt angles range from 42-58°. In the second Sb site, Sb(2) is bonded to two equivalent O(1), two equivalent O(3), and two equivalent O(4) atoms to form SbO6 octahedra that share corners with two equivalent Ca(1)O6 octahedra, corners with two equivalent Sb(1)O6 octahedra, corners with two equivalent Sb(2)O6 octahedra, and edges with two equivalent Ca(2)O8 hexagonal bipyramids. The corner-sharing octahedral tilt angles range from 41-57°. There are five inequivalent O sites. In the first O site, O(1) is bonded in a 4-coordinate geometry to one Ca(2), one Ca(3), and two equivalent Sb(2) atoms. In the second O site, O(2) is bonded to one Ca(2), one Ca(3), and two equivalent Pr(1) atoms to form OCa2Pr2 tetrahedra that share corners with two equivalent O(5)CaPr2Sb tetrahedra, corners with four equivalent O(2)Ca2Pr2 tetrahedra, corners with four equivalent O(4)Ca2PrSb tetrahedra,  an edgeedge with one O(5)CaPr2Sb tetrahedra, and edges with two equivalent O(4)Ca2PrSb tetrahedra. In the third O site, O(3) is bonded in a 4-coordinate geometry to one Ca(2), one Pr(1), one Sb(1), and one Sb(2) atom. In the fourth O site, O(4) is bonded to one Ca(1), one Ca(3), one Pr(1), and one Sb(2) atom to form distorted OCa2PrSb tetrahedra that share corners with two equivalent O(2)Ca2Pr2 tetrahedra, corners with two equivalent O(5)CaPr2Sb tetrahedra, corners with six equivalent O(4)Ca2PrSb tetrahedra,  an edgeedge with one O(2)Ca2Pr2 tetrahedra,  an edgeedge with one O(4)Ca2PrSb tetrahedra, and  an edgeedge with one O(5)CaPr2Sb tetrahedra. In the fifth O site, O(5) is bonded to one Ca(1), two equivalent Pr(1), and one Sb(1) atom to form distorted OCaPr2Sb tetrahedra that share corners with two equivalent O(2)Ca2Pr2 tetrahedra, corners with four equivalent O(4)Ca2PrSb tetrahedra, corners with four equivalent O(5)CaPr2Sb tetrahedra,  an edgeedge with one O(2)Ca2Pr2 tetrahedra, and edges with two equivalent O(4)Ca2PrSb tetrahedra.
Ca3Pr2Sb3O14 crystallizes in the monoclinic C2/m space group. There are three inequivalent Ca sites. In the first Ca site, Ca(1) is bonded to two equivalent O(5) and four equivalent O(4) atoms to form CaO6 octahedra that share corners with two equivalent Sb(1)O6 octahedra and corners with four equivalent Sb(2)O6 octahedra. The corner-sharing octahedral tilt angles range from 57-58°. Both Ca(1)-O(5) bond lengths are 2.31 Å. All Ca(1)-O(4) bond lengths are 2.33 Å. In the second Ca site, Ca(2) is bonded to two equivalent O(1), two equivalent O(2), and four equivalent O(3) atoms to form CaO8 hexagonal bipyramids that share edges with two equivalent Sb(1)O6 octahedra and edges with four equivalent Sb(2)O6 octahedra. Both Ca(2)-O(1) bond lengths are 2.64 Å. Both Ca(2)-O(2) bond lengths are 2.25 Å. All Ca(2)-O(3) bond lengths are 2.63 Å. In the third Ca site, Ca(3) is bonded in a distorted body-centered cubic geometry to two equivalent O(1), two equivalent O(2), and four equivalent O(4) atoms. Both Ca(3)-O(1) bond lengths are 2.86 Å. Both Ca(3)-O(2) bond lengths are 2.34 Å. All Ca(3)-O(4) bond lengths are 2.54 Å. Pr(1) is bonded in a distorted body-centered cubic geometry to two equivalent O(2), two equivalent O(3), two equivalent O(4), and two equivalent O(5) atoms. Both Pr(1)-O(2) bond lengths are 2.34 Å. Both Pr(1)-O(3) bond lengths are 2.82 Å. Both Pr(1)-O(4) bond lengths are 2.52 Å. Both Pr(1)-O(5) bond lengths are 2.53 Å. There are two inequivalent Sb sites. In the first Sb site, Sb(1) is bonded to two equivalent O(5) and four equivalent O(3) atoms to form SbO6 octahedra that share corners with two equivalent Ca(1)O6 octahedra, corners with four equivalent Sb(2)O6 octahedra, and edges with two equivalent Ca(2)O8 hexagonal bipyramids. The corner-sharing octahedral tilt angles range from 42-58°. Both Sb(1)-O(5) bond lengths are 1.97 Å. All Sb(1)-O(3) bond lengths are 2.04 Å. In the second Sb site, Sb(2) is bonded to two equivalent O(1), two equivalent O(3), and two equivalent O(4) atoms to form SbO6 octahedra that share corners with two equivalent Ca(1)O6 octahedra, corners with two equivalent Sb(1)O6 octahedra, corners with two equivalent Sb(2)O6 octahedra, and edges with two equivalent Ca(2)O8 hexagonal bipyramids. The corner-sharing octahedral tilt angles range from 41-57°. Both Sb(2)-O(1) bond lengths are 2.03 Å. Both Sb(2)-O(3) bond lengths are 2.04 Å. Both Sb(2)-O(4) bond lengths are 1.97 Å. There are five inequivalent O sites. In the first O site, O(1) is bonded in a 4-coordinate geometry to one Ca(2), one Ca(3), and two equivalent Sb(2) atoms. In the second O site, O(2) is bonded to one Ca(2), one Ca(3), and two equivalent Pr(1) atoms to form OCa2Pr2 tetrahedra that share corners with two equivalent O(5)CaPr2Sb tetrahedra, corners with four equivalent O(2)Ca2Pr2 tetrahedra, corners with four equivalent O(4)Ca2PrSb tetrahedra,  an edgeedge with one O(5)CaPr2Sb tetrahedra, and edges with two equivalent O(4)Ca2PrSb tetrahedra. In the third O site, O(3) is bonded in a 4-coordinate geometry to one Ca(2), one Pr(1), one Sb(1), and one Sb(2) atom. In the fourth O site, O(4) is bonded to one Ca(1), one Ca(3), one Pr(1), and one Sb(2) atom to form distorted OCa2PrSb tetrahedra that share corners with two equivalent O(2)Ca2Pr2 tetrahedra, corners with two equivalent O(5)CaPr2Sb tetrahedra, corners with six equivalent O(4)Ca2PrSb tetrahedra,  an edgeedge with one O(2)Ca2Pr2 tetrahedra,  an edgeedge with one O(4)Ca2PrSb tetrahedra, and  an edgeedge with one O(5)CaPr2Sb tetrahedra. In the fifth O site, O(5) is bonded to one Ca(1), two equivalent Pr(1), and one Sb(1) atom to form distorted OCaPr2Sb tetrahedra that share corners with two equivalent O(2)Ca2Pr2 tetrahedra, corners with four equivalent O(4)Ca2PrSb tetrahedra, corners with four equivalent O(5)CaPr2Sb tetrahedra,  an edgeedge with one O(2)Ca2Pr2 tetrahedra, and edges with two equivalent O(4)Ca2PrSb tetrahedra.