MgCo2(AsS)2 crystallizes in the monoclinic Pm space group. Mg(1) is bonded in a 8-coordinate geometry to two equivalent Co(2), one As(1), two equivalent As(2), one S(2), and two equivalent S(1) atoms. There are two inequivalent Co sites. In the first Co site, Co(1) is bonded to one As(2), two equivalent As(1), one S(1), and two equivalent S(2) atoms to form CoAs3S3 octahedra that share corners with two equivalent S(2)MgCo2As tetrahedra and edges with two equivalent Co(1)As3S3 octahedra. In the second Co site, Co(2) is bonded in a 7-coordinate geometry to two equivalent Mg(1), one As(1), two equivalent As(2), and two equivalent S(1) atoms. There are two inequivalent As sites. In the first As site, As(1) is bonded in a 5-coordinate geometry to one Mg(1), one Co(2), two equivalent Co(1), and one S(2) atom. In the second As site, As(2) is bonded in a 6-coordinate geometry to two equivalent Mg(1), one Co(1), two equivalent Co(2), and one S(1) atom. There are two inequivalent S sites. In the first S site, S(1) is bonded in a 5-coordinate geometry to two equivalent Mg(1), one Co(1), two equivalent Co(2), and one As(2) atom. In the second S site, S(2) is bonded to one Mg(1), two equivalent Co(1), and one As(1) atom to form SMgCo2As tetrahedra that share corners with two equivalent Co(1)As3S3 octahedra and corners with two equivalent S(2)MgCo2As tetrahedra. The corner-sharing octahedral tilt angles are 68°.
MgCo2(AsS)2 crystallizes in the monoclinic Pm space group. Mg(1) is bonded in a 8-coordinate geometry to two equivalent Co(2), one As(1), two equivalent As(2), one S(2), and two equivalent S(1) atoms. There is one shorter (2.58 Å) and one longer (2.59 Å) Mg(1)-Co(2) bond length. The Mg(1)-As(1) bond length is 3.08 Å. Both Mg(1)-As(2) bond lengths are 2.86 Å. The Mg(1)-S(2) bond length is 2.44 Å. Both Mg(1)-S(1) bond lengths are 2.51 Å. There are two inequivalent Co sites. In the first Co site, Co(1) is bonded to one As(2), two equivalent As(1), one S(1), and two equivalent S(2) atoms to form CoAs3S3 octahedra that share corners with two equivalent S(2)MgCo2As tetrahedra and edges with two equivalent Co(1)As3S3 octahedra. The Co(1)-As(2) bond length is 2.34 Å. Both Co(1)-As(1) bond lengths are 2.39 Å. The Co(1)-S(1) bond length is 2.28 Å. Both Co(1)-S(2) bond lengths are 2.32 Å. In the second Co site, Co(2) is bonded in a 7-coordinate geometry to two equivalent Mg(1), one As(1), two equivalent As(2), and two equivalent S(1) atoms. The Co(2)-As(1) bond length is 2.42 Å. Both Co(2)-As(2) bond lengths are 2.29 Å. Both Co(2)-S(1) bond lengths are 2.35 Å. There are two inequivalent As sites. In the first As site, As(1) is bonded in a 5-coordinate geometry to one Mg(1), one Co(2), two equivalent Co(1), and one S(2) atom. The As(1)-S(2) bond length is 2.45 Å. In the second As site, As(2) is bonded in a 6-coordinate geometry to two equivalent Mg(1), one Co(1), two equivalent Co(2), and one S(1) atom. The As(2)-S(1) bond length is 2.81 Å. There are two inequivalent S sites. In the first S site, S(1) is bonded in a 5-coordinate geometry to two equivalent Mg(1), one Co(1), two equivalent Co(2), and one As(2) atom. In the second S site, S(2) is bonded to one Mg(1), two equivalent Co(1), and one As(1) atom to form SMgCo2As tetrahedra that share corners with two equivalent Co(1)As3S3 octahedra and corners with two equivalent S(2)MgCo2As tetrahedra. The corner-sharing octahedral tilt angles are 68°.