Materials Data on Ba(FeSe2)2 by Materials Project
BaFe2Se4 crystallizes in the tetragonal I4/m space group. The structure is three-dimensional. Ba2+ is bonded to twelve equivalent Se2- atoms to form BaSe12 cuboctahedra that share corners with eight equivalent FeSe4 tetrahedra, edges with eight equivalent BaSe12 cuboctahedra, edges with eight equivalent FeSe4 tetrahedra, and faces with two equivalent BaSe12 cuboctahedra. There are four shorter (3.41 Å) and eight longer (3.69 Å) Ba–Se bond lengths. Fe3+ is bonded to four equivalent Se2- atoms to form FeSe4 tetrahedra that share corners with four equivalent BaSe12 cuboctahedra, edges with four equivalent BaSe12 cuboctahedra, and edges with two equivalent FeSe4 tetrahedra. All Fe–Se bond lengths are 2.27 Å. Se2- is bonded in a 5-coordinate geometry to three equivalent Ba2+ and two equivalent Fe3+ atoms.