Mn20Si12C crystallizes in the monoclinic P2/m space group. There are eight inequivalent Mn sites. In the first Mn site, Mn(1) is bonded in a 6-coordinate geometry to two equivalent Si(1), two equivalent Si(3), and two equivalent Si(4) atoms. In the second Mn site, Mn(2) is bonded in a 6-coordinate geometry to two equivalent Si(2), two equivalent Si(3), and two equivalent Si(4) atoms. In the third Mn site, Mn(3) is bonded in a 6-coordinate geometry to two equivalent Si(2), two equivalent Si(3), and two equivalent Si(4) atoms. In the fourth Mn site, Mn(4) is bonded in a 6-coordinate geometry to two equivalent Si(1), two equivalent Si(3), and two equivalent Si(4) atoms. In the fifth Mn site, Mn(5) is bonded in a 5-coordinate geometry to two equivalent Si(4) and three equivalent Si(1) atoms. In the sixth Mn site, Mn(6) is bonded in a distorted single-bond geometry to two equivalent Si(3), three equivalent Si(2), and one C(1) atom. In the seventh Mn site, Mn(7) is bonded in a 5-coordinate geometry to one Si(1), one Si(3), and three equivalent Si(4) atoms. In the eighth Mn site, Mn(8) is bonded in a distorted single-bond geometry to one Si(2), one Si(4), three equivalent Si(3), and one C(1) atom. There are four inequivalent Si sites. In the first Si site, Si(1) is bonded in a 9-coordinate geometry to two equivalent Mn(1), two equivalent Mn(4), two equivalent Mn(7), and three equivalent Mn(5) atoms. In the second Si site, Si(2) is bonded in a 9-coordinate geometry to two equivalent Mn(2), two equivalent Mn(3), two equivalent Mn(8), and three equivalent Mn(6) atoms. In the third Si site, Si(3) is bonded in a 9-coordinate geometry to one Mn(1), one Mn(2), one Mn(3), one Mn(4), one Mn(6), one Mn(7), and three equivalent Mn(8) atoms. In the fourth Si site, Si(4) is bonded in a 9-coordinate geometry to one Mn(1), one Mn(2), one Mn(3), one Mn(4), one Mn(5), one Mn(8), and three equivalent Mn(7) atoms. C(1) is bonded in an octahedral geometry to two equivalent Mn(6) and four equivalent Mn(8) atoms.
Mn20Si12C crystallizes in the monoclinic P2/m space group. There are eight inequivalent Mn sites. In the first Mn site, Mn(1) is bonded in a 6-coordinate geometry to two equivalent Si(1), two equivalent Si(3), and two equivalent Si(4) atoms. Both Mn(1)-Si(1) bond lengths are 2.44 Å. Both Mn(1)-Si(3) bond lengths are 2.43 Å. Both Mn(1)-Si(4) bond lengths are 2.42 Å. In the second Mn site, Mn(2) is bonded in a 6-coordinate geometry to two equivalent Si(2), two equivalent Si(3), and two equivalent Si(4) atoms. Both Mn(2)-Si(2) bond lengths are 2.42 Å. Both Mn(2)-Si(3) bond lengths are 2.45 Å. Both Mn(2)-Si(4) bond lengths are 2.43 Å. In the third Mn site, Mn(3) is bonded in a 6-coordinate geometry to two equivalent Si(2), two equivalent Si(3), and two equivalent Si(4) atoms. Both Mn(3)-Si(2) bond lengths are 2.40 Å. Both Mn(3)-Si(3) bond lengths are 2.39 Å. Both Mn(3)-Si(4) bond lengths are 2.41 Å. In the fourth Mn site, Mn(4) is bonded in a 6-coordinate geometry to two equivalent Si(1), two equivalent Si(3), and two equivalent Si(4) atoms. Both Mn(4)-Si(1) bond lengths are 2.42 Å. Both Mn(4)-Si(3) bond lengths are 2.40 Å. Both Mn(4)-Si(4) bond lengths are 2.42 Å. In the fifth Mn site, Mn(5) is bonded in a 5-coordinate geometry to two equivalent Si(4) and three equivalent Si(1) atoms. Both Mn(5)-Si(4) bond lengths are 2.40 Å. There are a spread of Mn(5)-Si(1) bond distances ranging from 2.47-2.63 Å. In the sixth Mn site, Mn(6) is bonded in a distorted single-bond geometry to two equivalent Si(3), three equivalent Si(2), and one C(1) atom. Both Mn(6)-Si(3) bond lengths are 2.40 Å. There are a spread of Mn(6)-Si(2) bond distances ranging from 2.47-2.67 Å. The Mn(6)-C(1) bond length is 2.00 Å. In the seventh Mn site, Mn(7) is bonded in a 5-coordinate geometry to one Si(1), one Si(3), and three equivalent Si(4) atoms. The Mn(7)-Si(1) bond length is 2.39 Å. The Mn(7)-Si(3) bond length is 2.43 Å. There is one shorter (2.39 Å) and two longer (2.62 Å) Mn(7)-Si(4) bond lengths. In the eighth Mn site, Mn(8) is bonded in a distorted single-bond geometry to one Si(2), one Si(4), three equivalent Si(3), and one C(1) atom. The Mn(8)-Si(2) bond length is 2.41 Å. The Mn(8)-Si(4) bond length is 2.49 Å. There are a spread of Mn(8)-Si(3) bond distances ranging from 2.40-2.66 Å. The Mn(8)-C(1) bond length is 2.00 Å. There are four inequivalent Si sites. In the first Si site, Si(1) is bonded in a 9-coordinate geometry to two equivalent Mn(1), two equivalent Mn(4), two equivalent Mn(7), and three equivalent Mn(5) atoms. In the second Si site, Si(2) is bonded in a 9-coordinate geometry to two equivalent Mn(2), two equivalent Mn(3), two equivalent Mn(8), and three equivalent Mn(6) atoms. In the third Si site, Si(3) is bonded in a 9-coordinate geometry to one Mn(1), one Mn(2), one Mn(3), one Mn(4), one Mn(6), one Mn(7), and three equivalent Mn(8) atoms. In the fourth Si site, Si(4) is bonded in a 9-coordinate geometry to one Mn(1), one Mn(2), one Mn(3), one Mn(4), one Mn(5), one Mn(8), and three equivalent Mn(7) atoms. C(1) is bonded in an octahedral geometry to two equivalent Mn(6) and four equivalent Mn(8) atoms.