ErFe2Co2B crystallizes in the orthorhombic Cmm2 space group. There are two inequivalent Er sites. In the first Er site, Er(1) is bonded in a 6-coordinate geometry to six equivalent Co(1) atoms. In the second Er site, Er(2) is bonded in a 18-coordinate geometry to two equivalent Fe(1), two equivalent Fe(3), four equivalent Fe(2), four equivalent Co(2), and six equivalent B(1) atoms. There are three inequivalent Fe sites. In the first Fe site, Fe(1) is bonded in a 2-coordinate geometry to two equivalent Er(2), two equivalent Co(1), and two equivalent B(1) atoms. In the second Fe site, Fe(2) is bonded in a 2-coordinate geometry to two equivalent Er(2), two equivalent Co(1), and two equivalent B(1) atoms. In the third Fe site, Fe(3) is bonded in a 2-coordinate geometry to two equivalent Er(2), two equivalent Co(1), and two equivalent B(1) atoms. There are two inequivalent Co sites. In the first Co site, Co(1) is bonded in a 9-coordinate geometry to three equivalent Er(1), one Fe(1), one Fe(3), two equivalent Fe(2), and two equivalent Co(2) atoms. In the second Co site, Co(2) is bonded in a distorted L-shaped geometry to two equivalent Er(2), two equivalent Co(1), and two equivalent B(1) atoms. B(1) is bonded in a 6-coordinate geometry to three equivalent Er(2), one Fe(1), one Fe(3), two equivalent Fe(2), and two equivalent Co(2) atoms.
ErFe2Co2B crystallizes in the orthorhombic Cmm2 space group. There are two inequivalent Er sites. In the first Er site, Er(1) is bonded in a 6-coordinate geometry to six equivalent Co(1) atoms. All Er(1)-Co(1) bond lengths are 2.89 Å. In the second Er site, Er(2) is bonded in a 18-coordinate geometry to two equivalent Fe(1), two equivalent Fe(3), four equivalent Fe(2), four equivalent Co(2), and six equivalent B(1) atoms. Both Er(2)-Fe(1) bond lengths are 2.92 Å. Both Er(2)-Fe(3) bond lengths are 2.94 Å. All Er(2)-Fe(2) bond lengths are 2.92 Å. All Er(2)-Co(2) bond lengths are 2.87 Å. There are two shorter (2.84 Å) and four longer (2.91 Å) Er(2)-B(1) bond lengths. There are three inequivalent Fe sites. In the first Fe site, Fe(1) is bonded in a 2-coordinate geometry to two equivalent Er(2), two equivalent Co(1), and two equivalent B(1) atoms. Both Fe(1)-Co(1) bond lengths are 2.41 Å. Both Fe(1)-B(1) bond lengths are 2.08 Å. In the second Fe site, Fe(2) is bonded in a 2-coordinate geometry to two equivalent Er(2), two equivalent Co(1), and two equivalent B(1) atoms. Both Fe(2)-Co(1) bond lengths are 2.46 Å. Both Fe(2)-B(1) bond lengths are 2.09 Å. In the third Fe site, Fe(3) is bonded in a 2-coordinate geometry to two equivalent Er(2), two equivalent Co(1), and two equivalent B(1) atoms. Both Fe(3)-Co(1) bond lengths are 2.43 Å. Both Fe(3)-B(1) bond lengths are 2.09 Å. There are two inequivalent Co sites. In the first Co site, Co(1) is bonded in a 9-coordinate geometry to three equivalent Er(1), one Fe(1), one Fe(3), two equivalent Fe(2), and two equivalent Co(2) atoms. Both Co(1)-Co(2) bond lengths are 2.48 Å. In the second Co site, Co(2) is bonded in a distorted L-shaped geometry to two equivalent Er(2), two equivalent Co(1), and two equivalent B(1) atoms. Both Co(2)-B(1) bond lengths are 2.04 Å. B(1) is bonded in a 6-coordinate geometry to three equivalent Er(2), one Fe(1), one Fe(3), two equivalent Fe(2), and two equivalent Co(2) atoms.