CaEr4Zr4O14 crystallizes in the orthorhombic Pmm2 space group. Ca(1) is bonded to two equivalent O(4), two equivalent O(6), and two equivalent O(8) atoms to form distorted CaO6 octahedra that share corners with two equivalent Zr(2)O6 octahedra,  an edgeedge with one Zr(2)O6 octahedra, and edges with two equivalent Ca(1)O6 octahedra. The corner-sharing octahedral tilt angles are 10°. There are three inequivalent Er sites. In the first Er site, Er(1) is bonded to one O(1), one O(10), two equivalent O(2), and two equivalent O(9) atoms to form ErO6 octahedra that share corners with two equivalent Er(1)O6 octahedra, edges with two equivalent Er(1)O6 octahedra, and edges with two equivalent Zr(2)O6 octahedra. The corner-sharing octahedral tilt angles range from 46-56°. In the second Er site, Er(2) is bonded in a 6-coordinate geometry to two equivalent O(2), two equivalent O(3), and two equivalent O(6) atoms. In the third Er site, Er(3) is bonded in a 6-coordinate geometry to two equivalent O(5), two equivalent O(8), and two equivalent O(9) atoms. There are three inequivalent Zr sites. In the first Zr site, Zr(1) is bonded in a distorted body-centered cubic geometry to two equivalent O(1), two equivalent O(5), two equivalent O(7), and two equivalent O(9) atoms. In the second Zr site, Zr(2) is bonded to two equivalent O(10), two equivalent O(2), and two equivalent O(4) atoms to form distorted ZrO6 octahedra that share corners with two equivalent Ca(1)O6 octahedra,  an edgeedge with one Ca(1)O6 octahedra, edges with two equivalent Zr(2)O6 octahedra, and edges with four equivalent Er(1)O6 octahedra. The corner-sharing octahedral tilt angles are 10°. In the third Zr site, Zr(3) is bonded in a 7-coordinate geometry to one O(3), one O(7), one O(8), two equivalent O(5), and two equivalent O(6) atoms. There are ten inequivalent O sites. In the first O site, O(1) is bonded to two equivalent Er(1) and two equivalent Zr(1) atoms to form OEr2Zr2 tetrahedra that share corners with two equivalent O(1)Er2Zr2 tetrahedra, corners with two equivalent O(10)Er2Zr2 tetrahedra, corners with two equivalent O(7)Zr4 tetrahedra, corners with four equivalent O(5)ErZr3 tetrahedra, and  an edgeedge with one O(7)Zr4 tetrahedra. In the second O site, O(2) is bonded in a rectangular see-saw-like geometry to one Er(2), two equivalent Er(1), and one Zr(2) atom. In the third O site, O(3) is bonded to two equivalent Er(2) and two equivalent Zr(3) atoms to form OEr2Zr2 tetrahedra that share corners with two equivalent O(8)Ca2Er2Zr2 octahedra, corners with two equivalent O(3)Er2Zr2 tetrahedra, corners with four equivalent O(5)ErZr3 tetrahedra, and  an edgeedge with one O(7)Zr4 tetrahedra. The corner-sharing octahedral tilt angles are 30°. In the fourth O site, O(4) is bonded in a rectangular see-saw-like geometry to two equivalent Ca(1) and two equivalent Zr(2) atoms. In the fifth O site, O(5) is bonded to one Er(3), one Zr(1), and two equivalent Zr(3) atoms to form distorted OErZr3 tetrahedra that share corners with two equivalent O(1)Er2Zr2 tetrahedra, corners with two equivalent O(3)Er2Zr2 tetrahedra, corners with four equivalent O(5)ErZr3 tetrahedra, edges with two equivalent O(8)Ca2Er2Zr2 octahedra, and edges with two equivalent O(7)Zr4 tetrahedra. In the sixth O site, O(6) is bonded in a distorted see-saw-like geometry to one Ca(1), one Er(2), and two equivalent Zr(3) atoms. In the seventh O site, O(7) is bonded to two equivalent Zr(1) and two equivalent Zr(3) atoms to form OZr4 tetrahedra that share corners with two equivalent O(8)Ca2Er2Zr2 octahedra, corners with two equivalent O(1)Er2Zr2 tetrahedra, corners with two equivalent O(7)Zr4 tetrahedra,  an edgeedge with one O(1)Er2Zr2 tetrahedra,  an edgeedge with one O(3)Er2Zr2 tetrahedra, and edges with four equivalent O(5)ErZr3 tetrahedra. The corner-sharing octahedral tilt angles are 69°. In the eighth O site, O(8) is bonded to two equivalent Ca(1), two equivalent Er(3), and two equivalent Zr(3) atoms to form distorted OCa2Er2Zr2 octahedra that share corners with two equivalent O(3)Er2Zr2 tetrahedra, corners with two equivalent O(7)Zr4 tetrahedra, edges with two equivalent O(8)Ca2Er2Zr2 octahedra, and edges with four equivalent O(5)ErZr3 tetrahedra. In the ninth O site, O(9) is bonded in a 4-coordinate geometry to one Er(3), two equivalent Er(1), and one Zr(1) atom. In the tenth O site, O(10) is bonded to two equivalent Er(1) and two equivalent Zr(2) atoms to form corner-sharing OEr2Zr2 tetrahedra.
CaEr4Zr4O14 crystallizes in the orthorhombic Pmm2 space group. Ca(1) is bonded to two equivalent O(4), two equivalent O(6), and two equivalent O(8) atoms to form distorted CaO6 octahedra that share corners with two equivalent Zr(2)O6 octahedra,  an edgeedge with one Zr(2)O6 octahedra, and edges with two equivalent Ca(1)O6 octahedra. The corner-sharing octahedral tilt angles are 10°. Both Ca(1)-O(4) bond lengths are 2.51 Å. Both Ca(1)-O(6) bond lengths are 2.17 Å. Both Ca(1)-O(8) bond lengths are 2.41 Å. There are three inequivalent Er sites. In the first Er site, Er(1) is bonded to one O(1), one O(10), two equivalent O(2), and two equivalent O(9) atoms to form ErO6 octahedra that share corners with two equivalent Er(1)O6 octahedra, edges with two equivalent Er(1)O6 octahedra, and edges with two equivalent Zr(2)O6 octahedra. The corner-sharing octahedral tilt angles range from 46-56°. The Er(1)-O(1) bond length is 2.23 Å. The Er(1)-O(10) bond length is 2.20 Å. Both Er(1)-O(2) bond lengths are 2.40 Å. Both Er(1)-O(9) bond lengths are 2.21 Å. In the second Er site, Er(2) is bonded in a 6-coordinate geometry to two equivalent O(2), two equivalent O(3), and two equivalent O(6) atoms. Both Er(2)-O(2) bond lengths are 2.41 Å. Both Er(2)-O(3) bond lengths are 2.07 Å. Both Er(2)-O(6) bond lengths are 2.43 Å. In the third Er site, Er(3) is bonded in a 6-coordinate geometry to two equivalent O(5), two equivalent O(8), and two equivalent O(9) atoms. Both Er(3)-O(5) bond lengths are 2.36 Å. Both Er(3)-O(8) bond lengths are 2.27 Å. Both Er(3)-O(9) bond lengths are 2.27 Å. There are three inequivalent Zr sites. In the first Zr site, Zr(1) is bonded in a distorted body-centered cubic geometry to two equivalent O(1), two equivalent O(5), two equivalent O(7), and two equivalent O(9) atoms. Both Zr(1)-O(1) bond lengths are 2.33 Å. Both Zr(1)-O(5) bond lengths are 2.23 Å. Both Zr(1)-O(7) bond lengths are 2.03 Å. Both Zr(1)-O(9) bond lengths are 2.76 Å. In the second Zr site, Zr(2) is bonded to two equivalent O(10), two equivalent O(2), and two equivalent O(4) atoms to form distorted ZrO6 octahedra that share corners with two equivalent Ca(1)O6 octahedra,  an edgeedge with one Ca(1)O6 octahedra, edges with two equivalent Zr(2)O6 octahedra, and edges with four equivalent Er(1)O6 octahedra. The corner-sharing octahedral tilt angles are 10°. Both Zr(2)-O(10) bond lengths are 2.21 Å. Both Zr(2)-O(2) bond lengths are 2.24 Å. Both Zr(2)-O(4) bond lengths are 2.15 Å. In the third Zr site, Zr(3) is bonded in a 7-coordinate geometry to one O(3), one O(7), one O(8), two equivalent O(5), and two equivalent O(6) atoms. The Zr(3)-O(3) bond length is 2.21 Å. The Zr(3)-O(7) bond length is 2.18 Å. The Zr(3)-O(8) bond length is 2.72 Å. Both Zr(3)-O(5) bond lengths are 2.28 Å. Both Zr(3)-O(6) bond lengths are 2.19 Å. There are ten inequivalent O sites. In the first O site, O(1) is bonded to two equivalent Er(1) and two equivalent Zr(1) atoms to form OEr2Zr2 tetrahedra that share corners with two equivalent O(1)Er2Zr2 tetrahedra, corners with two equivalent O(10)Er2Zr2 tetrahedra, corners with two equivalent O(7)Zr4 tetrahedra, corners with four equivalent O(5)ErZr3 tetrahedra, and  an edgeedge with one O(7)Zr4 tetrahedra. In the second O site, O(2) is bonded in a rectangular see-saw-like geometry to one Er(2), two equivalent Er(1), and one Zr(2) atom. In the third O site, O(3) is bonded to two equivalent Er(2) and two equivalent Zr(3) atoms to form OEr2Zr2 tetrahedra that share corners with two equivalent O(8)Ca2Er2Zr2 octahedra, corners with two equivalent O(3)Er2Zr2 tetrahedra, corners with four equivalent O(5)ErZr3 tetrahedra, and  an edgeedge with one O(7)Zr4 tetrahedra. The corner-sharing octahedral tilt angles are 30°. In the fourth O site, O(4) is bonded in a rectangular see-saw-like geometry to two equivalent Ca(1) and two equivalent Zr(2) atoms. In the fifth O site, O(5) is bonded to one Er(3), one Zr(1), and two equivalent Zr(3) atoms to form distorted OErZr3 tetrahedra that share corners with two equivalent O(1)Er2Zr2 tetrahedra, corners with two equivalent O(3)Er2Zr2 tetrahedra, corners with four equivalent O(5)ErZr3 tetrahedra, edges with two equivalent O(8)Ca2Er2Zr2 octahedra, and edges with two equivalent O(7)Zr4 tetrahedra. In the sixth O site, O(6) is bonded in a distorted see-saw-like geometry to one Ca(1), one Er(2), and two equivalent Zr(3) atoms. In the seventh O site, O(7) is bonded to two equivalent Zr(1) and two equivalent Zr(3) atoms to form OZr4 tetrahedra that share corners with two equivalent O(8)Ca2Er2Zr2 octahedra, corners with two equivalent O(1)Er2Zr2 tetrahedra, corners with two equivalent O(7)Zr4 tetrahedra,  an edgeedge with one O(1)Er2Zr2 tetrahedra,  an edgeedge with one O(3)Er2Zr2 tetrahedra, and edges with four equivalent O(5)ErZr3 tetrahedra. The corner-sharing octahedral tilt angles are 69°. In the eighth O site, O(8) is bonded to two equivalent Ca(1), two equivalent Er(3), and two equivalent Zr(3) atoms to form distorted OCa2Er2Zr2 octahedra that share corners with two equivalent O(3)Er2Zr2 tetrahedra, corners with two equivalent O(7)Zr4 tetrahedra, edges with two equivalent O(8)Ca2Er2Zr2 octahedra, and edges with four equivalent O(5)ErZr3 tetrahedra. In the ninth O site, O(9) is bonded in a 4-coordinate geometry to one Er(3), two equivalent Er(1), and one Zr(1) atom. In the tenth O site, O(10) is bonded to two equivalent Er(1) and two equivalent Zr(2) atoms to form corner-sharing OEr2Zr2 tetrahedra.