Eu(BiSe2)2 crystallizes in the orthorhombic Pnma space group. Eu(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 Bi sites. In the first Bi site, Bi(1) is bonded to one Se(2), two equivalent Se(4), and three equivalent Se(1) atoms to form a mixture of corner and edge-sharing BiSe6 octahedra. The corner-sharing octahedral tilt angles range from 48-70°. In the second Bi site, Bi(2) is bonded to one Se(4), two equivalent Se(2), and three equivalent Se(3) atoms to form a mixture of corner and edge-sharing BiSe6 octahedra. The corner-sharing octahedral tilt angles range from 48-70°. There are four inequivalent Se sites. In the first Se site, Se(1) is bonded to two equivalent Eu(1) and three equivalent Bi(1) atoms to form a mixture of corner and edge-sharing SeEu2Bi3 square pyramids. In the second Se site, Se(2) is bonded to two equivalent Eu(1), one Bi(1), and two equivalent Bi(2) atoms to form a mixture of distorted corner and edge-sharing SeEu2Bi3 trigonal bipyramids. In the third Se site, Se(3) is bonded to two equivalent Eu(1) and three equivalent Bi(2) atoms to form a mixture of corner and edge-sharing SeEu2Bi3 trigonal bipyramids. In the fourth Se site, Se(4) is bonded to two equivalent Eu(1), one Bi(2), and two equivalent Bi(1) atoms to form a mixture of distorted corner and edge-sharing SeEu2Bi3 trigonal bipyramids.
Eu(BiSe2)2 crystallizes in the orthorhombic Pnma space group. Eu(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 Eu(1)-Se(1) bond lengths are 3.20 Å. Both Eu(1)-Se(2) bond lengths are 3.19 Å. Both Eu(1)-Se(3) bond lengths are 3.24 Å. There is one shorter (3.24 Å) and one longer (3.67 Å) Eu(1)-Se(4) bond length. There are two inequivalent Bi sites. In the first Bi site, Bi(1) is bonded to one Se(2), two equivalent Se(4), and three equivalent Se(1) atoms to form a mixture of corner and edge-sharing BiSe6 octahedra. The corner-sharing octahedral tilt angles range from 48-70°. The Bi(1)-Se(2) bond length is 2.95 Å. Both Bi(1)-Se(4) bond lengths are 2.86 Å. There is one shorter (2.94 Å) and two longer (3.07 Å) Bi(1)-Se(1) bond lengths. In the second Bi site, Bi(2) is bonded to one Se(4), two equivalent Se(2), and three equivalent Se(3) atoms to form a mixture of corner and edge-sharing BiSe6 octahedra. The corner-sharing octahedral tilt angles range from 48-70°. The Bi(2)-Se(4) bond length is 2.95 Å. Both Bi(2)-Se(2) bond lengths are 3.00 Å. There are two shorter (2.96 Å) and one longer (3.00 Å) Bi(2)-Se(3) bond length. There are four inequivalent Se sites. In the first Se site, Se(1) is bonded to two equivalent Eu(1) and three equivalent Bi(1) atoms to form a mixture of corner and edge-sharing SeEu2Bi3 square pyramids. In the second Se site, Se(2) is bonded to two equivalent Eu(1), one Bi(1), and two equivalent Bi(2) atoms to form a mixture of distorted corner and edge-sharing SeEu2Bi3 trigonal bipyramids. In the third Se site, Se(3) is bonded to two equivalent Eu(1) and three equivalent Bi(2) atoms to form a mixture of corner and edge-sharing SeEu2Bi3 trigonal bipyramids. In the fourth Se site, Se(4) is bonded to two equivalent Eu(1), one Bi(2), and two equivalent Bi(1) atoms to form a mixture of distorted corner and edge-sharing SeEu2Bi3 trigonal bipyramids.