Ba(TmSe2)2 crystallizes in the orthorhombic Pnma space group. Ba(1) is bonded in a 8-coordinate geometry to two equivalent Se(1), two equivalent Se(2), two equivalent Se(3), and two equivalent Se(4) atoms. There are two inequivalent Tm sites. In the first Tm site, Tm(1) is bonded to one Se(2), two equivalent Se(4), and three equivalent Se(3) atoms to form a mixture of corner and edge-sharing TmSe6 octahedra. The corner-sharing octahedral tilt angles range from 48-58°. In the second Tm site, Tm(2) is bonded to one Se(4), two equivalent Se(2), and three equivalent Se(1) atoms to form a mixture of corner and edge-sharing TmSe6 octahedra. The corner-sharing octahedral tilt angles range from 48-58°. There are four inequivalent Se sites. In the first Se site, Se(1) is bonded to two equivalent Ba(1) and three equivalent Tm(2) atoms to form a mixture of distorted corner and edge-sharing SeBa2Tm3 trigonal bipyramids. In the second Se site, Se(2) is bonded in a 5-coordinate geometry to two equivalent Ba(1), one Tm(1), and two equivalent Tm(2) atoms. In the third Se site, Se(3) is bonded to two equivalent Ba(1) and three equivalent Tm(1) atoms to form a mixture of corner and edge-sharing SeBa2Tm3 square pyramids. In the fourth Se site, Se(4) is bonded to two equivalent Ba(1), one Tm(2), and two equivalent Tm(1) atoms to form a mixture of distorted corner and edge-sharing SeBa2Tm3 trigonal bipyramids.
Ba(TmSe2)2 crystallizes in the orthorhombic Pnma space group. Ba(1) is bonded in a 8-coordinate geometry to two equivalent Se(1), two equivalent Se(2), two equivalent Se(3), and two equivalent Se(4) atoms. Both Ba(1)-Se(1) bond lengths are 3.33 Å. Both Ba(1)-Se(2) bond lengths are 3.39 Å. Both Ba(1)-Se(3) bond lengths are 3.31 Å. There is one shorter (3.47 Å) and one longer (3.48 Å) Ba(1)-Se(4) bond length. There are two inequivalent Tm sites. In the first Tm site, Tm(1) is bonded to one Se(2), two equivalent Se(4), and three equivalent Se(3) atoms to form a mixture of corner and edge-sharing TmSe6 octahedra. The corner-sharing octahedral tilt angles range from 48-58°. The Tm(1)-Se(2) bond length is 2.88 Å. Both Tm(1)-Se(4) bond lengths are 2.80 Å. There is one shorter (2.82 Å) and two longer (2.84 Å) Tm(1)-Se(3) bond lengths. In the second Tm site, Tm(2) is bonded to one Se(4), two equivalent Se(2), and three equivalent Se(1) atoms to form a mixture of corner and edge-sharing TmSe6 octahedra. The corner-sharing octahedral tilt angles range from 48-58°. The Tm(2)-Se(4) bond length is 2.85 Å. Both Tm(2)-Se(2) bond lengths are 2.86 Å. There is one shorter (2.79 Å) and two longer (2.84 Å) Tm(2)-Se(1) bond lengths. There are four inequivalent Se sites. In the first Se site, Se(1) is bonded to two equivalent Ba(1) and three equivalent Tm(2) atoms to form a mixture of distorted corner and edge-sharing SeBa2Tm3 trigonal bipyramids. In the second Se site, Se(2) is bonded in a 5-coordinate geometry to two equivalent Ba(1), one Tm(1), and two equivalent Tm(2) atoms. In the third Se site, Se(3) is bonded to two equivalent Ba(1) and three equivalent Tm(1) atoms to form a mixture of corner and edge-sharing SeBa2Tm3 square pyramids. In the fourth Se site, Se(4) is bonded to two equivalent Ba(1), one Tm(2), and two equivalent Tm(1) atoms to form a mixture of distorted corner and edge-sharing SeBa2Tm3 trigonal bipyramids.