Tm4(B2O5)3 crystallizes in the monoclinic C2/c space group. There are two inequivalent Tm sites. In the first Tm site, Tm(1) is bonded in a 8-coordinate geometry to one O(2), one O(8), two equivalent O(3), two equivalent O(5), and two equivalent O(6) atoms. In the second Tm site, Tm(2) is bonded in a 8-coordinate geometry to one O(1), one O(2), one O(3), one O(4), one O(5), one O(6), and two equivalent O(7) atoms. There are three inequivalent B sites. In the first B site, B(1) is bonded to one O(1), one O(2), one O(4), and one O(5) atom to form corner-sharing BO4 tetrahedra. In the second B site, B(2) is bonded to one O(1), one O(3), one O(6), and one O(8) atom to form corner-sharing BO4 tetrahedra. In the third B site, B(3) is bonded to one O(2), one O(4), and two equivalent O(7) atoms to form a mixture of edge and corner-sharing BO4 tetrahedra. There are eight inequivalent O sites. In the first O site, O(8) is bonded in a 4-coordinate geometry to two equivalent Tm(1) and two equivalent B(2) atoms. In the second O site, O(1) is bonded in a 3-coordinate geometry to one Tm(2), one B(1), and one B(2) atom. In the third O site, O(2) is bonded in a distorted bent 120 degrees geometry to one Tm(1), one Tm(2), one B(1), and one B(3) atom. In the fourth O site, O(3) is bonded in a 4-coordinate geometry to one Tm(2), two equivalent Tm(1), and one B(2) atom. In the fifth O site, O(4) is bonded in a 3-coordinate geometry to one Tm(2), one B(1), and one B(3) atom. In the sixth O site, O(5) is bonded in a 4-coordinate geometry to one Tm(2), two equivalent Tm(1), and one B(1) atom. In the seventh O site, O(6) is bonded in a 4-coordinate geometry to one Tm(2), two equivalent Tm(1), and one B(2) atom. In the eighth O site, O(7) is bonded in a distorted L-shaped geometry to two equivalent Tm(2) and two equivalent B(3) atoms.
Tm4(B2O5)3 crystallizes in the monoclinic C2/c space group. There are two inequivalent Tm sites. In the first Tm site, Tm(1) is bonded in a 8-coordinate geometry to one O(2), one O(8), two equivalent O(3), two equivalent O(5), and two equivalent O(6) atoms. The Tm(1)-O(2) bond length is 2.63 Å. The Tm(1)-O(8) bond length is 2.32 Å. There is one shorter (2.23 Å) and one longer (2.50 Å) Tm(1)-O(3) bond length. There is one shorter (2.34 Å) and one longer (2.63 Å) Tm(1)-O(5) bond length. There is one shorter (2.22 Å) and one longer (2.48 Å) Tm(1)-O(6) bond length. In the second Tm site, Tm(2) is bonded in a 8-coordinate geometry to one O(1), one O(2), one O(3), one O(4), one O(5), one O(6), and two equivalent O(7) atoms. The Tm(2)-O(1) bond length is 2.21 Å. The Tm(2)-O(2) bond length is 2.64 Å. The Tm(2)-O(3) bond length is 2.25 Å. The Tm(2)-O(4) bond length is 2.26 Å. The Tm(2)-O(5) bond length is 2.20 Å. The Tm(2)-O(6) bond length is 2.46 Å. There is one shorter (2.56 Å) and one longer (2.58 Å) Tm(2)-O(7) bond length. There are three inequivalent B sites. In the first B site, B(1) is bonded to one O(1), one O(2), one O(4), and one O(5) atom to form corner-sharing BO4 tetrahedra. The B(1)-O(1) bond length is 1.48 Å. The B(1)-O(2) bond length is 1.51 Å. The B(1)-O(4) bond length is 1.48 Å. The B(1)-O(5) bond length is 1.46 Å. In the second B site, B(2) is bonded to one O(1), one O(3), one O(6), and one O(8) atom to form corner-sharing BO4 tetrahedra. The B(2)-O(1) bond length is 1.50 Å. The B(2)-O(3) bond length is 1.44 Å. The B(2)-O(6) bond length is 1.46 Å. The B(2)-O(8) bond length is 1.51 Å. In the third B site, B(3) is bonded to one O(2), one O(4), and two equivalent O(7) atoms to form a mixture of edge and corner-sharing BO4 tetrahedra. The B(3)-O(2) bond length is 1.46 Å. The B(3)-O(4) bond length is 1.46 Å. There is one shorter (1.51 Å) and one longer (1.55 Å) B(3)-O(7) bond length. There are eight inequivalent O sites. In the first O site, O(8) is bonded in a 4-coordinate geometry to two equivalent Tm(1) and two equivalent B(2) atoms. In the second O site, O(1) is bonded in a 3-coordinate geometry to one Tm(2), one B(1), and one B(2) atom. In the third O site, O(2) is bonded in a distorted bent 120 degrees geometry to one Tm(1), one Tm(2), one B(1), and one B(3) atom. In the fourth O site, O(3) is bonded in a 4-coordinate geometry to one Tm(2), two equivalent Tm(1), and one B(2) atom. In the fifth O site, O(4) is bonded in a 3-coordinate geometry to one Tm(2), one B(1), and one B(3) atom. In the sixth O site, O(5) is bonded in a 4-coordinate geometry to one Tm(2), two equivalent Tm(1), and one B(1) atom. In the seventh O site, O(6) is bonded in a 4-coordinate geometry to one Tm(2), two equivalent Tm(1), and one B(2) atom. In the eighth O site, O(7) is bonded in a distorted L-shaped geometry to two equivalent Tm(2) and two equivalent B(3) atoms.