CaTe3O8 crystallizes in the monoclinic C2/c space group. Ca(1) is bonded in a 8-coordinate geometry to two equivalent O(1), two equivalent O(2), two equivalent O(3), and two equivalent O(4) atoms. There are two inequivalent Te sites. In the first Te site, Te(1) is bonded to two equivalent O(2), two equivalent O(3), and two equivalent O(4) atoms to form corner-sharing TeO6 octahedra. In the second Te site, Te(2) is bonded to one O(2), one O(3), one O(4), and two equivalent O(1) atoms to form distorted TeO5 square pyramids that share corners with three equivalent Te(1)O6 octahedra and  an edgeedge with one Te(2)O5 square pyramid. The corner-sharing octahedral tilt angles range from 46-62°. There are four inequivalent O sites. In the first O site, O(1) is bonded in a distorted trigonal planar geometry to one Ca(1) and two equivalent Te(2) atoms. In the second O site, O(2) is bonded in a distorted trigonal planar geometry to one Ca(1), one Te(1), and one Te(2) atom. In the third O site, O(3) is bonded in a distorted trigonal planar geometry to one Ca(1), one Te(1), and one Te(2) atom. In the fourth O site, O(4) is bonded in a distorted trigonal planar geometry to one Ca(1), one Te(1), and one Te(2) atom.
CaTe3O8 crystallizes in the monoclinic C2/c space group. Ca(1) is bonded in a 8-coordinate geometry to two equivalent O(1), two equivalent O(2), two equivalent O(3), and two equivalent O(4) atoms. Both Ca(1)-O(1) bond lengths are 2.36 Å. Both Ca(1)-O(2) bond lengths are 2.51 Å. Both Ca(1)-O(3) bond lengths are 2.54 Å. Both Ca(1)-O(4) bond lengths are 2.45 Å. There are two inequivalent Te sites. In the first Te site, Te(1) is bonded to two equivalent O(2), two equivalent O(3), and two equivalent O(4) atoms to form corner-sharing TeO6 octahedra. Both Te(1)-O(2) bond lengths are 1.97 Å. Both Te(1)-O(3) bond lengths are 1.94 Å. Both Te(1)-O(4) bond lengths are 1.89 Å. In the second Te site, Te(2) is bonded to one O(2), one O(3), one O(4), and two equivalent O(1) atoms to form distorted TeO5 square pyramids that share corners with three equivalent Te(1)O6 octahedra and  an edgeedge with one Te(2)O5 square pyramid. The corner-sharing octahedral tilt angles range from 46-62°. The Te(2)-O(2) bond length is 1.97 Å. The Te(2)-O(3) bond length is 2.11 Å. The Te(2)-O(4) bond length is 2.38 Å. There is one shorter (1.92 Å) and one longer (2.10 Å) Te(2)-O(1) bond length. There are four inequivalent O sites. In the first O site, O(1) is bonded in a distorted trigonal planar geometry to one Ca(1) and two equivalent Te(2) atoms. In the second O site, O(2) is bonded in a distorted trigonal planar geometry to one Ca(1), one Te(1), and one Te(2) atom. In the third O site, O(3) is bonded in a distorted trigonal planar geometry to one Ca(1), one Te(1), and one Te(2) atom. In the fourth O site, O(4) is bonded in a distorted trigonal planar geometry to one Ca(1), one Te(1), and one Te(2) atom.