Ca4NdO(BO3)3 crystallizes in the monoclinic Cm space group. There are two inequivalent Ca sites. In the first Ca site, Ca(1) is bonded to one O(2), one O(5), two equivalent O(3), and two equivalent O(6) atoms to form CaO6 octahedra that share  a cornercorner with one Ca(1)O6 octahedra, corners with two equivalent Nd(1)O6 octahedra, and edges with two equivalent Ca(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 67-77°. In the second Ca site, Ca(2) is bonded in a 6-coordinate geometry to one O(3), one O(6), two equivalent O(1), and two equivalent O(5) atoms. Nd(1) is bonded to two equivalent O(1), two equivalent O(2), and two equivalent O(4) atoms to form distorted NdO6 octahedra that share corners with four equivalent Ca(1)O6 octahedra and edges with two equivalent Nd(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 67-68°. There are two inequivalent B sites. In the first B site, B(1) is bonded in a trigonal planar geometry to one O(4) and two equivalent O(3) atoms. In the second B site, B(2) is bonded in a trigonal planar geometry to one O(1), one O(5), and one O(6) atom. There are six inequivalent O sites. In the first O site, O(1) is bonded to two equivalent Ca(2), one Nd(1), and one B(2) atom to form distorted OCa2NdB tetrahedra that share corners with two equivalent O(2)Ca2Nd2 tetrahedra, corners with two equivalent O(3)Ca3B tetrahedra, and corners with three equivalent O(1)Ca2NdB tetrahedra. In the second O site, O(2) is bonded to two equivalent Ca(1) and two equivalent Nd(1) atoms to form OCa2Nd2 tetrahedra that share corners with two equivalent O(2)Ca2Nd2 tetrahedra, corners with four equivalent O(1)Ca2NdB tetrahedra, and corners with four equivalent O(3)Ca3B tetrahedra. In the third O site, O(3) is bonded to one Ca(2), two equivalent Ca(1), and one B(1) atom to form distorted OCa3B tetrahedra that share corners with two equivalent O(2)Ca2Nd2 tetrahedra, corners with two equivalent O(1)Ca2NdB tetrahedra, and corners with three equivalent O(3)Ca3B tetrahedra. In the fourth O site, O(4) is bonded in a 1-coordinate geometry to two equivalent Nd(1) and one B(1) atom. In the fifth O site, O(5) is bonded in a 1-coordinate geometry to one Ca(1), two equivalent Ca(2), and one B(2) atom. In the sixth O site, O(6) is bonded in a 1-coordinate geometry to one Ca(2), two equivalent Ca(1), and one B(2) atom.
Ca4NdO(BO3)3 crystallizes in the monoclinic Cm space group. There are two inequivalent Ca sites. In the first Ca site, Ca(1) is bonded to one O(2), one O(5), two equivalent O(3), and two equivalent O(6) atoms to form CaO6 octahedra that share  a cornercorner with one Ca(1)O6 octahedra, corners with two equivalent Nd(1)O6 octahedra, and edges with two equivalent Ca(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 67-77°. The Ca(1)-O(2) bond length is 2.34 Å. The Ca(1)-O(5) bond length is 2.36 Å. There is one shorter (2.39 Å) and one longer (2.40 Å) Ca(1)-O(3) bond length. There is one shorter (2.35 Å) and one longer (2.42 Å) Ca(1)-O(6) bond length. In the second Ca site, Ca(2) is bonded in a 6-coordinate geometry to one O(3), one O(6), two equivalent O(1), and two equivalent O(5) atoms. The Ca(2)-O(3) bond length is 2.35 Å. The Ca(2)-O(6) bond length is 2.52 Å. There is one shorter (2.36 Å) and one longer (2.38 Å) Ca(2)-O(1) bond length. There is one shorter (2.50 Å) and one longer (2.64 Å) Ca(2)-O(5) bond length. Nd(1) is bonded to two equivalent O(1), two equivalent O(2), and two equivalent O(4) atoms to form distorted NdO6 octahedra that share corners with four equivalent Ca(1)O6 octahedra and edges with two equivalent Nd(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 67-68°. Both Nd(1)-O(1) bond lengths are 2.46 Å. There is one shorter (2.30 Å) and one longer (2.31 Å) Nd(1)-O(2) bond length. There is one shorter (2.41 Å) and one longer (2.50 Å) Nd(1)-O(4) bond length. There are two inequivalent B sites. In the first B site, B(1) is bonded in a trigonal planar geometry to one O(4) and two equivalent O(3) atoms. The B(1)-O(4) bond length is 1.39 Å. Both B(1)-O(3) bond lengths are 1.39 Å. In the second B site, B(2) is bonded in a trigonal planar geometry to one O(1), one O(5), and one O(6) atom. The B(2)-O(1) bond length is 1.40 Å. The B(2)-O(5) bond length is 1.38 Å. The B(2)-O(6) bond length is 1.39 Å. There are six inequivalent O sites. In the first O site, O(1) is bonded to two equivalent Ca(2), one Nd(1), and one B(2) atom to form distorted OCa2NdB tetrahedra that share corners with two equivalent O(2)Ca2Nd2 tetrahedra, corners with two equivalent O(3)Ca3B tetrahedra, and corners with three equivalent O(1)Ca2NdB tetrahedra. In the second O site, O(2) is bonded to two equivalent Ca(1) and two equivalent Nd(1) atoms to form OCa2Nd2 tetrahedra that share corners with two equivalent O(2)Ca2Nd2 tetrahedra, corners with four equivalent O(1)Ca2NdB tetrahedra, and corners with four equivalent O(3)Ca3B tetrahedra. In the third O site, O(3) is bonded to one Ca(2), two equivalent Ca(1), and one B(1) atom to form distorted OCa3B tetrahedra that share corners with two equivalent O(2)Ca2Nd2 tetrahedra, corners with two equivalent O(1)Ca2NdB tetrahedra, and corners with three equivalent O(3)Ca3B tetrahedra. In the fourth O site, O(4) is bonded in a 1-coordinate geometry to two equivalent Nd(1) and one B(1) atom. In the fifth O site, O(5) is bonded in a 1-coordinate geometry to one Ca(1), two equivalent Ca(2), and one B(2) atom. In the sixth O site, O(6) is bonded in a 1-coordinate geometry to one Ca(2), two equivalent Ca(1), and one B(2) atom.