Er3MnB7 crystallizes in the orthorhombic Cmcm space group. There are two inequivalent Er sites. In the first Er site, Er(1) is bonded in a 11-coordinate geometry to two equivalent B(2), two equivalent B(4), three equivalent B(1), and four equivalent B(3) atoms. In the second Er site, Er(2) is bonded in a 10-coordinate geometry to four equivalent B(2) and six equivalent B(1) atoms. Mn(1) is bonded in a 10-coordinate geometry to two equivalent B(4), four equivalent B(2), and four equivalent B(3) atoms. There are four inequivalent B sites. In the first B site, B(1) is bonded in a 9-coordinate geometry to three equivalent Er(1), three equivalent Er(2), one B(2), and two equivalent B(1) atoms. In the second B site, B(2) is bonded in a 9-coordinate geometry to two equivalent Er(1), two equivalent Er(2), two equivalent Mn(1), one B(1), one B(2), and one B(3) atom. In the third B site, B(3) is bonded in a 9-coordinate geometry to four equivalent Er(1), two equivalent Mn(1), one B(2), one B(3), and one B(4) atom. In the fourth B site, B(4) is bonded in a 8-coordinate geometry to four equivalent Er(1), two equivalent Mn(1), and two equivalent B(3) atoms.
Er3MnB7 crystallizes in the orthorhombic Cmcm space group. There are two inequivalent Er sites. In the first Er site, Er(1) is bonded in a 11-coordinate geometry to two equivalent B(2), two equivalent B(4), three equivalent B(1), and four equivalent B(3) atoms. Both Er(1)-B(2) bond lengths are 2.64 Å. Both Er(1)-B(4) bond lengths are 2.64 Å. There is one shorter (2.64 Å) and two longer (2.71 Å) Er(1)-B(1) bond lengths. There are two shorter (2.60 Å) and two longer (2.62 Å) Er(1)-B(3) bond lengths. In the second Er site, Er(2) is bonded in a 10-coordinate geometry to four equivalent B(2) and six equivalent B(1) atoms. All Er(2)-B(2) bond lengths are 2.60 Å. There are four shorter (2.65 Å) and two longer (2.66 Å) Er(2)-B(1) bond lengths. Mn(1) is bonded in a 10-coordinate geometry to two equivalent B(4), four equivalent B(2), and four equivalent B(3) atoms. Both Mn(1)-B(4) bond lengths are 2.26 Å. All Mn(1)-B(2) bond lengths are 2.28 Å. All Mn(1)-B(3) bond lengths are 2.27 Å. There are four inequivalent B sites. In the first B site, B(1) is bonded in a 9-coordinate geometry to three equivalent Er(1), three equivalent Er(2), one B(2), and two equivalent B(1) atoms. The B(1)-B(2) bond length is 1.88 Å. Both B(1)-B(1) bond lengths are 1.95 Å. In the second B site, B(2) is bonded in a 9-coordinate geometry to two equivalent Er(1), two equivalent Er(2), two equivalent Mn(1), one B(1), one B(2), and one B(3) atom. The B(2)-B(2) bond length is 1.80 Å. The B(2)-B(3) bond length is 1.78 Å. In the third B site, B(3) is bonded in a 9-coordinate geometry to four equivalent Er(1), two equivalent Mn(1), one B(2), one B(3), and one B(4) atom. The B(3)-B(3) bond length is 1.92 Å. The B(3)-B(4) bond length is 1.72 Å. In the fourth B site, B(4) is bonded in a 8-coordinate geometry to four equivalent Er(1), two equivalent Mn(1), and two equivalent B(3) atoms.