BaFe2As2 crystallizes in the monoclinic C2/m space group. There are two inequivalent Ba sites. In the first Ba site, Ba(1) is bonded in a body-centered cubic geometry to four equivalent As(1) and four equivalent As(2) atoms. In the second Ba site, Ba(2) is bonded in a body-centered cubic geometry to four equivalent As(1) and four equivalent As(2) atoms. There are two inequivalent Fe sites. In the first Fe site, Fe(1) is bonded to one As(2) and three equivalent As(1) atoms to form a mixture of corner and edge-sharing FeAs4 tetrahedra. In the second Fe site, Fe(2) is bonded to one As(1) and three equivalent As(2) atoms to form a mixture of corner and edge-sharing FeAs4 tetrahedra. There are two inequivalent As sites. In the first As site, As(1) is bonded in a 8-coordinate geometry to two equivalent Ba(1), two equivalent Ba(2), one Fe(2), and three equivalent Fe(1) atoms. In the second As site, As(2) is bonded in a 8-coordinate geometry to two equivalent Ba(1), two equivalent Ba(2), one Fe(1), and three equivalent Fe(2) atoms.
BaFe2As2 crystallizes in the monoclinic C2/m space group. There are two inequivalent Ba sites. In the first Ba site, Ba(1) is bonded in a body-centered cubic geometry to four equivalent As(1) and four equivalent As(2) atoms. All Ba(1)-As(1) bond lengths are 3.43 Å. All Ba(1)-As(2) bond lengths are 3.37 Å. In the second Ba site, Ba(2) is bonded in a body-centered cubic geometry to four equivalent As(1) and four equivalent As(2) atoms. All Ba(2)-As(1) bond lengths are 3.46 Å. All Ba(2)-As(2) bond lengths are 3.41 Å. There are two inequivalent Fe sites. In the first Fe site, Fe(1) is bonded to one As(2) and three equivalent As(1) atoms to form a mixture of corner and edge-sharing FeAs4 tetrahedra. The Fe(1)-As(2) bond length is 2.34 Å. There is one shorter (2.34 Å) and two longer (2.35 Å) Fe(1)-As(1) bond lengths. In the second Fe site, Fe(2) is bonded to one As(1) and three equivalent As(2) atoms to form a mixture of corner and edge-sharing FeAs4 tetrahedra. The Fe(2)-As(1) bond length is 2.39 Å. There are two shorter (2.39 Å) and one longer (2.40 Å) Fe(2)-As(2) bond length. There are two inequivalent As sites. In the first As site, As(1) is bonded in a 8-coordinate geometry to two equivalent Ba(1), two equivalent Ba(2), one Fe(2), and three equivalent Fe(1) atoms. In the second As site, As(2) is bonded in a 8-coordinate geometry to two equivalent Ba(1), two equivalent Ba(2), one Fe(1), and three equivalent Fe(2) atoms.