CaMn28 is alpha-derived structured and crystallizes in the cubic I-43m space group. Ca(1) is bonded in a 16-coordinate geometry to four equivalent Mn(1) and twelve equivalent Mn(3) atoms. There are three inequivalent Mn sites. In the first Mn site, Mn(1) is bonded in a 16-coordinate geometry to one Ca(1), six equivalent Mn(2), and nine equivalent Mn(3) atoms. In the second Mn site, Mn(3) is bonded in a 12-coordinate geometry to one Ca(1), three equivalent Mn(1), three equivalent Mn(3), and five equivalent Mn(2) atoms. In the third Mn site, Mn(2) is bonded in a 13-coordinate geometry to two equivalent Mn(1), five equivalent Mn(3), and six equivalent Mn(2) atoms.
CaMn28 is alpha-derived structured and crystallizes in the cubic I-43m space group. Ca(1) is bonded in a 16-coordinate geometry to four equivalent Mn(1) and twelve equivalent Mn(3) atoms. All Ca(1)-Mn(1) bond lengths are 2.83 Å. All Ca(1)-Mn(3) bond lengths are 2.79 Å. There are three inequivalent Mn sites. In the first Mn site, Mn(1) is bonded in a 16-coordinate geometry to one Ca(1), six equivalent Mn(2), and nine equivalent Mn(3) atoms. There are three shorter (2.50 Å) and three longer (2.86 Å) Mn(1)-Mn(2) bond lengths. There are six shorter (2.73 Å) and three longer (2.77 Å) Mn(1)-Mn(3) bond lengths. In the second Mn site, Mn(3) is bonded in a 12-coordinate geometry to one Ca(1), three equivalent Mn(1), three equivalent Mn(3), and five equivalent Mn(2) atoms. There is one shorter (2.23 Å) and two longer (2.49 Å) Mn(3)-Mn(3) bond lengths. There are a spread of Mn(3)-Mn(2) bond distances ranging from 2.23-2.60 Å. In the third Mn site, Mn(2) is bonded in a 13-coordinate geometry to two equivalent Mn(1), five equivalent Mn(3), and six equivalent Mn(2) atoms. There are two shorter (2.59 Å) and four longer (2.61 Å) Mn(2)-Mn(2) bond lengths.