MnO2 crystallizes in the trigonal R3m space group. There are two inequivalent Mn sites. In the first Mn site, Mn(1) is bonded to one O(2) and three equivalent O(1) atoms to form corner-sharing MnO4 tetrahedra. The corner-sharing octahedral tilt angles range from 57-59°. In the second Mn site, Mn(2) is bonded to one O(2), one O(3), two equivalent O(1), and two equivalent O(4) atoms to form MnO6 octahedra that share corners with three equivalent Mn(1)O4 tetrahedra and edges with four equivalent Mn(2)O6 octahedra. There are four inequivalent O sites. In the first O site, O(1) is bonded in a trigonal planar geometry to one Mn(1) and two equivalent Mn(2) atoms. In the second O site, O(2) is bonded in a distorted trigonal pyramidal geometry to one Mn(1) and three equivalent Mn(2) atoms. In the third O site, O(3) is bonded in a distorted T-shaped geometry to three equivalent Mn(2) atoms. In the fourth O site, O(4) is bonded in a water-like geometry to two equivalent Mn(2) atoms.
MnO2 crystallizes in the trigonal R3m space group. There are two inequivalent Mn sites. In the first Mn site, Mn(1) is bonded to one O(2) and three equivalent O(1) atoms to form corner-sharing MnO4 tetrahedra. The corner-sharing octahedral tilt angles range from 57-59°. The Mn(1)-O(2) bond length is 2.08 Å. All Mn(1)-O(1) bond lengths are 1.95 Å. In the second Mn site, Mn(2) is bonded to one O(2), one O(3), two equivalent O(1), and two equivalent O(4) atoms to form MnO6 octahedra that share corners with three equivalent Mn(1)O4 tetrahedra and edges with four equivalent Mn(2)O6 octahedra. The Mn(2)-O(2) bond length is 2.02 Å. The Mn(2)-O(3) bond length is 1.95 Å. Both Mn(2)-O(1) bond lengths are 1.95 Å. Both Mn(2)-O(4) bond lengths are 1.87 Å. There are four inequivalent O sites. In the first O site, O(1) is bonded in a trigonal planar geometry to one Mn(1) and two equivalent Mn(2) atoms. In the second O site, O(2) is bonded in a distorted trigonal pyramidal geometry to one Mn(1) and three equivalent Mn(2) atoms. In the third O site, O(3) is bonded in a distorted T-shaped geometry to three equivalent Mn(2) atoms. In the fourth O site, O(4) is bonded in a water-like geometry to two equivalent Mn(2) atoms.