Ca4GdB3O10 crystallizes in the monoclinic Cm space group. There are two inequivalent Ca sites. In the first Ca site, Ca(1) is bonded in a 6-coordinate geometry to one O(4), one O(5), two equivalent O(2), and two equivalent O(6) atoms. In the second Ca site, Ca(2) is bonded to one O(2), one O(3), two equivalent O(4), and two equivalent O(5) atoms to form CaO6 octahedra that share  a cornercorner with one Ca(2)O6 octahedra, corners with two equivalent Gd(1)O6 octahedra, and edges with two equivalent Ca(2)O6 octahedra. The corner-sharing octahedral tilt angles range from 67-79°. Gd(1) is bonded to two equivalent O(1), two equivalent O(3), and two equivalent O(6) atoms to form distorted GdO6 octahedra that share corners with four equivalent Ca(2)O6 octahedra and edges with two equivalent Gd(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(2), one O(5), and one O(6) atom. In the second B site, B(2) is bonded in a trigonal planar geometry to one O(1) and two equivalent O(4) atoms. There are six inequivalent O sites. In the first O site, O(1) is bonded in a 3-coordinate geometry to two equivalent Gd(1) and one B(2) atom. In the second O site, O(2) is bonded in a 1-coordinate geometry to one Ca(2), two equivalent Ca(1), and one B(1) atom. In the third O site, O(3) is bonded to two equivalent Ca(2) and two equivalent Gd(1) atoms to form OCa2Gd2 tetrahedra that share corners with two equivalent O(3)Ca2Gd2 tetrahedra, corners with four equivalent O(6)Ca2GdB tetrahedra, and corners with four equivalent O(4)Ca3B tetrahedra. In the fourth O site, O(4) is bonded to one Ca(1), two equivalent Ca(2), and one B(2) atom to form distorted OCa3B tetrahedra that share corners with two equivalent O(3)Ca2Gd2 tetrahedra, corners with two equivalent O(6)Ca2GdB tetrahedra, and corners with three equivalent O(4)Ca3B tetrahedra. In the fifth O site, O(5) is bonded in a 4-coordinate geometry to one Ca(1), two equivalent Ca(2), and one B(1) atom. In the sixth O site, O(6) is bonded to two equivalent Ca(1), one Gd(1), and one B(1) atom to form distorted OCa2GdB tetrahedra that share corners with two equivalent O(3)Ca2Gd2 tetrahedra, corners with two equivalent O(4)Ca3B tetrahedra, and corners with three equivalent O(6)Ca2GdB tetrahedra.
Ca4GdB3O10 crystallizes in the monoclinic Cm space group. There are two inequivalent Ca sites. In the first Ca site, Ca(1) is bonded in a 6-coordinate geometry to one O(4), one O(5), two equivalent O(2), and two equivalent O(6) atoms. The Ca(1)-O(4) bond length is 2.35 Å. The Ca(1)-O(5) bond length is 2.49 Å. There is one shorter (2.49 Å) and one longer (2.60 Å) Ca(1)-O(2) bond length. There is one shorter (2.36 Å) and one longer (2.38 Å) Ca(1)-O(6) bond length. In the second Ca site, Ca(2) is bonded to one O(2), one O(3), two equivalent O(4), and two equivalent O(5) atoms to form CaO6 octahedra that share  a cornercorner with one Ca(2)O6 octahedra, corners with two equivalent Gd(1)O6 octahedra, and edges with two equivalent Ca(2)O6 octahedra. The corner-sharing octahedral tilt angles range from 67-79°. The Ca(2)-O(2) bond length is 2.36 Å. The Ca(2)-O(3) bond length is 2.36 Å. There is one shorter (2.38 Å) and one longer (2.39 Å) Ca(2)-O(4) bond length. There is one shorter (2.33 Å) and one longer (2.39 Å) Ca(2)-O(5) bond length. Gd(1) is bonded to two equivalent O(1), two equivalent O(3), and two equivalent O(6) atoms to form distorted GdO6 octahedra that share corners with four equivalent Ca(2)O6 octahedra and edges with two equivalent Gd(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 67-68°. There is one shorter (2.36 Å) and one longer (2.44 Å) Gd(1)-O(1) bond length. There is one shorter (2.25 Å) and one longer (2.27 Å) Gd(1)-O(3) bond length. Both Gd(1)-O(6) bond lengths are 2.42 Å. There are two inequivalent B sites. In the first B site, B(1) is bonded in a trigonal planar geometry to one O(2), one O(5), and one O(6) atom. The B(1)-O(2) bond length is 1.38 Å. The B(1)-O(5) bond length is 1.39 Å. The B(1)-O(6) bond length is 1.40 Å. In the second B site, B(2) is bonded in a trigonal planar geometry to one O(1) and two equivalent O(4) atoms. The B(2)-O(1) bond length is 1.39 Å. Both B(2)-O(4) bond lengths are 1.39 Å. There are six inequivalent O sites. In the first O site, O(1) is bonded in a 3-coordinate geometry to two equivalent Gd(1) and one B(2) atom. In the second O site, O(2) is bonded in a 1-coordinate geometry to one Ca(2), two equivalent Ca(1), and one B(1) atom. In the third O site, O(3) is bonded to two equivalent Ca(2) and two equivalent Gd(1) atoms to form OCa2Gd2 tetrahedra that share corners with two equivalent O(3)Ca2Gd2 tetrahedra, corners with four equivalent O(6)Ca2GdB tetrahedra, and corners with four equivalent O(4)Ca3B tetrahedra. In the fourth O site, O(4) is bonded to one Ca(1), two equivalent Ca(2), and one B(2) atom to form distorted OCa3B tetrahedra that share corners with two equivalent O(3)Ca2Gd2 tetrahedra, corners with two equivalent O(6)Ca2GdB tetrahedra, and corners with three equivalent O(4)Ca3B tetrahedra. In the fifth O site, O(5) is bonded in a 4-coordinate geometry to one Ca(1), two equivalent Ca(2), and one B(1) atom. In the sixth O site, O(6) is bonded to two equivalent Ca(1), one Gd(1), and one B(1) atom to form distorted OCa2GdB tetrahedra that share corners with two equivalent O(3)Ca2Gd2 tetrahedra, corners with two equivalent O(4)Ca3B tetrahedra, and corners with three equivalent O(6)Ca2GdB tetrahedra.