MgMnO2 is Caswellsilverite-like structured and crystallizes in the trigonal R3m space group. Mg(1) is bonded in a 6-coordinate geometry to three equivalent O(1) and three equivalent O(2) atoms. Mn(1) is bonded to three equivalent O(1) and three equivalent O(2) atoms to form edge-sharing MnO6 octahedra. There are two inequivalent O sites. In the first O site, O(1) is bonded to three equivalent Mg(1) and three equivalent Mn(1) atoms to form a mixture of edge, face, and corner-sharing OMg3Mn3 octahedra. In the second O site, O(2) is bonded to three equivalent Mg(1) and three equivalent Mn(1) atoms to form a mixture of distorted edge, face, and corner-sharing OMg3Mn3 pentagonal pyramids. The corner-sharing octahedral tilt angles range from 0-47°.
MgMnO2 is Caswellsilverite-like structured and crystallizes in the trigonal R3m space group. Mg(1) is bonded in a 6-coordinate geometry to three equivalent O(1) and three equivalent O(2) atoms. All Mg(1)-O(1) bond lengths are 2.17 Å. All Mg(1)-O(2) bond lengths are 2.22 Å. Mn(1) is bonded to three equivalent O(1) and three equivalent O(2) atoms to form edge-sharing MnO6 octahedra. All Mn(1)-O(1) bond lengths are 2.23 Å. All Mn(1)-O(2) bond lengths are 2.24 Å. There are two inequivalent O sites. In the first O site, O(1) is bonded to three equivalent Mg(1) and three equivalent Mn(1) atoms to form a mixture of edge, face, and corner-sharing OMg3Mn3 octahedra. In the second O site, O(2) is bonded to three equivalent Mg(1) and three equivalent Mn(1) atoms to form a mixture of distorted edge, face, and corner-sharing OMg3Mn3 pentagonal pyramids. The corner-sharing octahedral tilt angles range from 0-47°.