LaCa4O(BO3)3 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(3), one O(5), two equivalent O(1), and two equivalent O(2) atoms. In the second Ca site, Ca(2) is bonded to one O(1), one O(4), two equivalent O(3), and two equivalent O(5) atoms to form a mixture of edge and corner-sharing CaO6 octahedra. The corner-sharing octahedral tilt angles are 75°. La(1) is bonded in a 6-coordinate geometry to two equivalent O(2), two equivalent O(4), and two equivalent O(6) atoms. There are two inequivalent B sites. In the first B site, B(1) is bonded in a trigonal planar geometry to one O(1), one O(2), and one O(3) atom. In the second B site, B(2) is bonded in a trigonal planar geometry to one O(6) and two equivalent O(5) atoms. There are six inequivalent O sites. In the first O site, O(1) is bonded in a 1-coordinate geometry to one Ca(2), two equivalent Ca(1), and one B(1) atom. In the second O site, O(2) is bonded to two equivalent Ca(1), one La(1), and one B(1) atom to form distorted OCa2LaB tetrahedra that share corners with two equivalent O(4)Ca2La2 tetrahedra, corners with two equivalent O(5)Ca3B tetrahedra, and corners with three equivalent O(2)Ca2LaB tetrahedra. In the third O site, O(3) is bonded in a 1-coordinate geometry to one Ca(1), two equivalent Ca(2), and one B(1) atom. In the fourth O site, O(4) is bonded to two equivalent Ca(2) and two equivalent La(1) atoms to form OCa2La2 tetrahedra that share corners with two equivalent O(4)Ca2La2 tetrahedra, corners with four equivalent O(2)Ca2LaB tetrahedra, and corners with four equivalent O(5)Ca3B tetrahedra. In the fifth O site, O(5) 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(4)Ca2La2 tetrahedra, corners with two equivalent O(2)Ca2LaB tetrahedra, and corners with three equivalent O(5)Ca3B tetrahedra. In the sixth O site, O(6) is bonded in a 1-coordinate geometry to two equivalent La(1) and one B(2) atom.
LaCa4O(BO3)3 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(3), one O(5), two equivalent O(1), and two equivalent O(2) atoms. The Ca(1)-O(3) bond length is 2.55 Å. The Ca(1)-O(5) bond length is 2.35 Å. There is one shorter (2.48 Å) and one longer (2.57 Å) Ca(1)-O(1) bond length. There is one shorter (2.36 Å) and one longer (2.38 Å) Ca(1)-O(2) bond length. In the second Ca site, Ca(2) is bonded to one O(1), one O(4), two equivalent O(3), and two equivalent O(5) atoms to form a mixture of edge and corner-sharing CaO6 octahedra. The corner-sharing octahedral tilt angles are 75°. The Ca(2)-O(1) bond length is 2.35 Å. The Ca(2)-O(4) bond length is 2.33 Å. There is one shorter (2.37 Å) and one longer (2.43 Å) Ca(2)-O(3) bond length. Both Ca(2)-O(5) bond lengths are 2.40 Å. La(1) is bonded in a 6-coordinate geometry to two equivalent O(2), two equivalent O(4), and two equivalent O(6) atoms. Both La(1)-O(2) bond lengths are 2.54 Å. There is one shorter (2.31 Å) and one longer (2.33 Å) La(1)-O(4) bond length. There is one shorter (2.45 Å) and one longer (2.55 Å) La(1)-O(6) 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(1), one O(2), and one O(3) atom. The B(1)-O(1) bond length is 1.39 Å. The B(1)-O(2) bond length is 1.40 Å. The B(1)-O(3) bond length is 1.39 Å. In the second B site, B(2) is bonded in a trigonal planar geometry to one O(6) and two equivalent O(5) atoms. The B(2)-O(6) bond length is 1.39 Å. Both B(2)-O(5) bond lengths are 1.39 Å. There are six inequivalent O sites. In the first O site, O(1) is bonded in a 1-coordinate geometry to one Ca(2), two equivalent Ca(1), and one B(1) atom. In the second O site, O(2) is bonded to two equivalent Ca(1), one La(1), and one B(1) atom to form distorted OCa2LaB tetrahedra that share corners with two equivalent O(4)Ca2La2 tetrahedra, corners with two equivalent O(5)Ca3B tetrahedra, and corners with three equivalent O(2)Ca2LaB tetrahedra. In the third O site, O(3) is bonded in a 1-coordinate geometry to one Ca(1), two equivalent Ca(2), and one B(1) atom. In the fourth O site, O(4) is bonded to two equivalent Ca(2) and two equivalent La(1) atoms to form OCa2La2 tetrahedra that share corners with two equivalent O(4)Ca2La2 tetrahedra, corners with four equivalent O(2)Ca2LaB tetrahedra, and corners with four equivalent O(5)Ca3B tetrahedra. In the fifth O site, O(5) 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(4)Ca2La2 tetrahedra, corners with two equivalent O(2)Ca2LaB tetrahedra, and corners with three equivalent O(5)Ca3B tetrahedra. In the sixth O site, O(6) is bonded in a 1-coordinate geometry to two equivalent La(1) and one B(2) atom.