K3Mn2O8 crystallizes in the monoclinic P2_1/m space group. There are three inequivalent K sites. In the first K site, K(1) is bonded in a 10-coordinate geometry to one O(1), two equivalent O(3), three equivalent O(2), and four equivalent O(6) atoms. In the second K site, K(2) is bonded in a 10-coordinate geometry to one O(5), two equivalent O(6), three equivalent O(4), and four equivalent O(3) atoms. In the third K site, K(3) is bonded in a 9-coordinate geometry to one O(2), one O(4), two equivalent O(3), two equivalent O(6), and three equivalent O(5) atoms. There are two inequivalent Mn sites. In the first Mn site, Mn(1) is bonded in a tetrahedral geometry to one O(4), one O(5), and two equivalent O(6) atoms. In the second Mn site, Mn(2) is bonded in a tetrahedral geometry to one O(1), one O(2), and two equivalent O(3) atoms. There are six inequivalent O sites. In the first O site, O(1) is bonded in a distorted linear geometry to one K(1) and one Mn(2) atom. In the second O site, O(2) is bonded in a single-bond geometry to one K(3), three equivalent K(1), and one Mn(2) atom. In the third O site, O(3) is bonded in a single-bond geometry to one K(1), one K(3), two equivalent K(2), and one Mn(2) atom. In the fourth O site, O(4) is bonded in a distorted single-bond geometry to one K(3), three equivalent K(2), and one Mn(1) atom. In the fifth O site, O(5) is bonded in a distorted single-bond geometry to one K(2), three equivalent K(3), and one Mn(1) atom. In the sixth O site, O(6) is bonded in a distorted single-bond geometry to one K(2), one K(3), two equivalent K(1), and one Mn(1) atom.
K3Mn2O8 crystallizes in the monoclinic P2_1/m space group. There are three inequivalent K sites. In the first K site, K(1) is bonded in a 10-coordinate geometry to one O(1), two equivalent O(3), three equivalent O(2), and four equivalent O(6) atoms. The K(1)-O(1) bond length is 2.70 Å. Both K(1)-O(3) bond lengths are 3.11 Å. There is one shorter (2.96 Å) and two longer (3.06 Å) K(1)-O(2) bond lengths. There are two shorter (2.79 Å) and two longer (2.93 Å) K(1)-O(6) bond lengths. In the second K site, K(2) is bonded in a 10-coordinate geometry to one O(5), two equivalent O(6), three equivalent O(4), and four equivalent O(3) atoms. The K(2)-O(5) bond length is 2.81 Å. Both K(2)-O(6) bond lengths are 2.96 Å. There is one shorter (2.90 Å) and two longer (2.97 Å) K(2)-O(4) bond lengths. There are two shorter (3.08 Å) and two longer (3.09 Å) K(2)-O(3) bond lengths. In the third K site, K(3) is bonded in a 9-coordinate geometry to one O(2), one O(4), two equivalent O(3), two equivalent O(6), and three equivalent O(5) atoms. The K(3)-O(2) bond length is 2.99 Å. The K(3)-O(4) bond length is 2.74 Å. Both K(3)-O(3) bond lengths are 2.95 Å. Both K(3)-O(6) bond lengths are 2.78 Å. There is one shorter (2.98 Å) and two longer (3.22 Å) K(3)-O(5) bond lengths. There are two inequivalent Mn sites. In the first Mn site, Mn(1) is bonded in a tetrahedral geometry to one O(4), one O(5), and two equivalent O(6) atoms. The Mn(1)-O(4) bond length is 1.67 Å. The Mn(1)-O(5) bond length is 1.65 Å. Both Mn(1)-O(6) bond lengths are 1.66 Å. In the second Mn site, Mn(2) is bonded in a tetrahedral geometry to one O(1), one O(2), and two equivalent O(3) atoms. The Mn(2)-O(1) bond length is 1.61 Å. The Mn(2)-O(2) bond length is 1.63 Å. Both Mn(2)-O(3) bond lengths are 1.63 Å. There are six inequivalent O sites. In the first O site, O(1) is bonded in a distorted linear geometry to one K(1) and one Mn(2) atom. In the second O site, O(2) is bonded in a single-bond geometry to one K(3), three equivalent K(1), and one Mn(2) atom. In the third O site, O(3) is bonded in a single-bond geometry to one K(1), one K(3), two equivalent K(2), and one Mn(2) atom. In the fourth O site, O(4) is bonded in a distorted single-bond geometry to one K(3), three equivalent K(2), and one Mn(1) atom. In the fifth O site, O(5) is bonded in a distorted single-bond geometry to one K(2), three equivalent K(3), and one Mn(1) atom. In the sixth O site, O(6) is bonded in a distorted single-bond geometry to one K(2), one K(3), two equivalent K(1), and one Mn(1) atom.