FeIr3 is beta Cu3Ti-like structured and crystallizes in the tetragonal I4/mmm space group. Fe(1) is bonded to four equivalent Ir(2) and eight equivalent Ir(1) atoms to form FeIr12 cuboctahedra that share corners with four equivalent Fe(1)Ir12 cuboctahedra, corners with eight equivalent Ir(2)Fe4Ir8 cuboctahedra, edges with eight equivalent Fe(1)Ir12 cuboctahedra, edges with sixteen equivalent Ir(1)Fe4Ir8 cuboctahedra, faces with four equivalent Fe(1)Ir12 cuboctahedra, faces with six equivalent Ir(2)Fe4Ir8 cuboctahedra, and faces with eight equivalent Ir(1)Fe4Ir8 cuboctahedra. There are two inequivalent Ir sites. In the first Ir site, Ir(1) is bonded to four equivalent Fe(1), four equivalent Ir(1), and four equivalent Ir(2) atoms to form IrFe4Ir8 cuboctahedra that share corners with twelve equivalent Ir(1)Fe4Ir8 cuboctahedra, edges with eight equivalent Fe(1)Ir12 cuboctahedra, edges with eight equivalent Ir(1)Fe4Ir8 cuboctahedra, edges with eight equivalent Ir(2)Fe4Ir8 cuboctahedra, faces with four equivalent Fe(1)Ir12 cuboctahedra, faces with four equivalent Ir(2)Fe4Ir8 cuboctahedra, and faces with ten equivalent Ir(1)Fe4Ir8 cuboctahedra. In the second Ir site, Ir(2) is bonded to four equivalent Fe(1) and eight equivalent Ir(1) atoms to form IrFe4Ir8 cuboctahedra that share corners with four equivalent Ir(2)Fe4Ir8 cuboctahedra, corners with eight equivalent Fe(1)Ir12 cuboctahedra, edges with eight equivalent Ir(2)Fe4Ir8 cuboctahedra, edges with sixteen equivalent Ir(1)Fe4Ir8 cuboctahedra, faces with four equivalent Ir(2)Fe4Ir8 cuboctahedra, faces with six equivalent Fe(1)Ir12 cuboctahedra, and faces with eight equivalent Ir(1)Fe4Ir8 cuboctahedra.
FeIr3 is beta Cu3Ti-like structured and crystallizes in the tetragonal I4/mmm space group. Fe(1) is bonded to four equivalent Ir(2) and eight equivalent Ir(1) atoms to form FeIr12 cuboctahedra that share corners with four equivalent Fe(1)Ir12 cuboctahedra, corners with eight equivalent Ir(2)Fe4Ir8 cuboctahedra, edges with eight equivalent Fe(1)Ir12 cuboctahedra, edges with sixteen equivalent Ir(1)Fe4Ir8 cuboctahedra, faces with four equivalent Fe(1)Ir12 cuboctahedra, faces with six equivalent Ir(2)Fe4Ir8 cuboctahedra, and faces with eight equivalent Ir(1)Fe4Ir8 cuboctahedra. All Fe(1)-Ir(2) bond lengths are 2.70 Å. All Fe(1)-Ir(1) bond lengths are 2.69 Å. There are two inequivalent Ir sites. In the first Ir site, Ir(1) is bonded to four equivalent Fe(1), four equivalent Ir(1), and four equivalent Ir(2) atoms to form IrFe4Ir8 cuboctahedra that share corners with twelve equivalent Ir(1)Fe4Ir8 cuboctahedra, edges with eight equivalent Fe(1)Ir12 cuboctahedra, edges with eight equivalent Ir(1)Fe4Ir8 cuboctahedra, edges with eight equivalent Ir(2)Fe4Ir8 cuboctahedra, faces with four equivalent Fe(1)Ir12 cuboctahedra, faces with four equivalent Ir(2)Fe4Ir8 cuboctahedra, and faces with ten equivalent Ir(1)Fe4Ir8 cuboctahedra. All Ir(1)-Ir(1) bond lengths are 2.70 Å. All Ir(1)-Ir(2) bond lengths are 2.69 Å. In the second Ir site, Ir(2) is bonded to four equivalent Fe(1) and eight equivalent Ir(1) atoms to form IrFe4Ir8 cuboctahedra that share corners with four equivalent Ir(2)Fe4Ir8 cuboctahedra, corners with eight equivalent Fe(1)Ir12 cuboctahedra, edges with eight equivalent Ir(2)Fe4Ir8 cuboctahedra, edges with sixteen equivalent Ir(1)Fe4Ir8 cuboctahedra, faces with four equivalent Ir(2)Fe4Ir8 cuboctahedra, faces with six equivalent Fe(1)Ir12 cuboctahedra, and faces with eight equivalent Ir(1)Fe4Ir8 cuboctahedra.