The compound described by MgMn5O8 crystallizes in the triclinic P1 space group. Mg(1) is bonded to one O(1), one O(4), one O(5), one O(6), and one O(7) atom to form MgO5 trigonal bipyramids that share  a cornercorner with one Mn(5)O6 octahedra, corners with two equivalent Mn(2)O5 square pyramids,  an edgeedge with one Mn(5)O6 octahedra, edges with two equivalent Mn(1)O6 octahedra,  an edgeedge with one Mn(2)O5 square pyramid, and  an edgeedge with one Mn(3)O5 square pyramid. The corner-sharing octahedral tilt angles are 72°. There are five inequivalent Mn sites. In the first Mn site, Mn(1) is bonded to one O(2), one O(3), one O(4), one O(5), one O(6), and one O(7) atom to form distorted MnO6 octahedra that share corners with four equivalent Mn(2)O5 square pyramids, edges with two equivalent Mn(5)O6 octahedra, edges with two equivalent Mn(3)O5 square pyramids, and edges with two equivalent Mg(1)O5 trigonal bipyramids. In the second Mn site, Mn(2) is bonded to one O(1), one O(3), one O(4), one O(5), and one O(6) atom to form distorted MnO5 square pyramids that share corners with three equivalent Mn(5)O6 octahedra, corners with four equivalent Mn(1)O6 octahedra,  a cornercorner with one Mn(3)O5 square pyramid, corners with two equivalent Mg(1)O5 trigonal bipyramids,  an edgeedge with one Mn(3)O5 square pyramid, and  an edgeedge with one Mg(1)O5 trigonal bipyramid. The corner-sharing octahedral tilt angles range from 24-68°. In the third Mn site, Mn(3) is bonded to one O(2), one O(3), one O(4), one O(5), and one O(8) atom to form MnO5 square pyramids that share  a cornercorner with one Mn(5)O6 octahedra,  a cornercorner with one Mn(2)O5 square pyramid,  an edgeedge with one Mn(5)O6 octahedra, edges with two equivalent Mn(1)O6 octahedra,  an edgeedge with one Mn(2)O5 square pyramid, and  an edgeedge with one Mg(1)O5 trigonal bipyramid. The corner-sharing octahedral tilt angles are 77°. In the fourth Mn site, Mn(4) is bonded in a 5-coordinate geometry to one O(1), one O(2), one O(4), one O(7), and one O(8) atom. In the fifth Mn site, Mn(5) is bonded to one O(1), one O(2), one O(3), one O(6), one O(7), and one O(8) atom to form MnO6 octahedra that share  a cornercorner with one Mn(3)O5 square pyramid, corners with three equivalent Mn(2)O5 square pyramids,  a cornercorner with one Mg(1)O5 trigonal bipyramid, edges with two equivalent Mn(1)O6 octahedra,  an edgeedge with one Mn(3)O5 square pyramid, and  an edgeedge with one Mg(1)O5 trigonal bipyramid. There are eight inequivalent O sites. In the first O site, O(1) is bonded in a rectangular see-saw-like geometry to one Mg(1), one Mn(2), one Mn(4), and one Mn(5) atom. In the second O site, O(2) is bonded to one Mn(1), one Mn(3), one Mn(4), and one Mn(5) atom to form distorted OMn4 trigonal pyramids that share  a cornercorner with one O(4)MgMn4 trigonal bipyramid, corners with three equivalent O(7)MgMn3 trigonal pyramids,  an edgeedge with one O(4)MgMn4 trigonal bipyramid, and  an edgeedge with one O(5)MgMn3 trigonal pyramid. In the third O site, O(3) is bonded in a distorted rectangular see-saw-like geometry to one Mn(1), one Mn(2), one Mn(3), and one Mn(5) atom. In the fourth O site, O(4) is bonded to one Mg(1), one Mn(1), one Mn(2), one Mn(3), and one Mn(4) atom to form distorted OMgMn4 trigonal bipyramids that share  a cornercorner with one O(7)MgMn3 trigonal pyramid,  a cornercorner with one O(2)Mn4 trigonal pyramid, corners with two equivalent O(5)MgMn3 trigonal pyramids,  an edgeedge with one O(5)MgMn3 trigonal pyramid,  an edgeedge with one O(7)MgMn3 trigonal pyramid, and  an edgeedge with one O(2)Mn4 trigonal pyramid. In the fifth O site, O(5) is bonded to one Mg(1), one Mn(1), one Mn(2), and one Mn(3) atom to form distorted OMgMn3 trigonal pyramids that share corners with two equivalent O(4)MgMn4 trigonal bipyramids, corners with two equivalent O(7)MgMn3 trigonal pyramids,  an edgeedge with one O(4)MgMn4 trigonal bipyramid, and  an edgeedge with one O(2)Mn4 trigonal pyramid. In the sixth O site, O(6) is bonded in a rectangular see-saw-like geometry to one Mg(1), one Mn(1), one Mn(2), and one Mn(5) atom. In the seventh O site, O(7) is bonded to one Mg(1), one Mn(1), one Mn(4), and one Mn(5) atom to form distorted OMgMn3 trigonal pyramids that share  a cornercorner with one O(4)MgMn4 trigonal bipyramid, corners with two equivalent O(5)MgMn3 trigonal pyramids, corners with three equivalent O(2)Mn4 trigonal pyramids, and  an edgeedge with one O(4)MgMn4 trigonal bipyramid. In the eighth O site, O(8) is bonded in a trigonal non-coplanar geometry to one Mn(3), one Mn(4), and one Mn(5) atom. is represented by the Crystallographic Information File (CIF) [CIF]
data_MgMn5O8
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   6.099
_cell_length_b   7.778
_cell_length_c   6.173
_cell_angle_alpha   108.940
_cell_angle_beta   62.458
_cell_angle_gamma   63.076
_symmetry_Int_Tables_number   1
_cell_volume   170.716
_cell_formula_units_Z   1
loop_
 _symmetry_equiv_pos_site_id
 _symmetry_equiv_pos_as_xyz
  1  'x, y, z'
loop_
 _atom_site_type_symbol
 _atom_site_label
 _atom_site_symmetry_multiplicity
 _atom_site_fract_x
 _atom_site_fract_y
 _atom_site_fract_z
 _atom_site_occupancy
  Mg  Mg0  1  0.656  0.040  0.761  1.0
  Mn  Mn1  1  0.021  0.509  0.483  1.0
  Mn  Mn2  1  0.897  0.071  0.117  1.0
  Mn  Mn3  1  0.336  0.988  0.230  1.0
  Mn  Mn4  1  0.014  0.526  0.979  1.0
  Mn  Mn5  1  0.508  0.512  0.992  1.0
  O  O6  1  0.536  0.285  0.671  1.0
  O  O7  1  0.078  0.319  0.632  1.0
  O  O8  1  0.375  0.758  0.933  1.0
  O  O9  1  0.864  0.796  0.858  1.0
  O  O10  1  0.155  0.216  0.144  1.0
  O  O11  1  0.598  0.289  0.083  1.0
  O  O12  1  0.952  0.701  0.338  1.0
  O  O13  1  0.500  0.740  0.280  1.0
[/CIF]
.
The compound described by MgMn5O8 crystallizes in the triclinic P1 space group. Mg(1) is bonded to one O(1), one O(4), one O(5), one O(6), and one O(7) atom to form MgO5 trigonal bipyramids that share  a cornercorner with one Mn(5)O6 octahedra, corners with two equivalent Mn(2)O5 square pyramids,  an edgeedge with one Mn(5)O6 octahedra, edges with two equivalent Mn(1)O6 octahedra,  an edgeedge with one Mn(2)O5 square pyramid, and  an edgeedge with one Mn(3)O5 square pyramid. The corner-sharing octahedral tilt angles are 72°. There are five inequivalent Mn sites. In the first Mn site, Mn(1) is bonded to one O(2), one O(3), one O(4), one O(5), one O(6), and one O(7) atom to form distorted MnO6 octahedra that share corners with four equivalent Mn(2)O5 square pyramids, edges with two equivalent Mn(5)O6 octahedra, edges with two equivalent Mn(3)O5 square pyramids, and edges with two equivalent Mg(1)O5 trigonal bipyramids. In the second Mn site, Mn(2) is bonded to one O(1), one O(3), one O(4), one O(5), and one O(6) atom to form distorted MnO5 square pyramids that share corners with three equivalent Mn(5)O6 octahedra, corners with four equivalent Mn(1)O6 octahedra,  a cornercorner with one Mn(3)O5 square pyramid, corners with two equivalent Mg(1)O5 trigonal bipyramids,  an edgeedge with one Mn(3)O5 square pyramid, and  an edgeedge with one Mg(1)O5 trigonal bipyramid. The corner-sharing octahedral tilt angles range from 24-68°. In the third Mn site, Mn(3) is bonded to one O(2), one O(3), one O(4), one O(5), and one O(8) atom to form MnO5 square pyramids that share  a cornercorner with one Mn(5)O6 octahedra,  a cornercorner with one Mn(2)O5 square pyramid,  an edgeedge with one Mn(5)O6 octahedra, edges with two equivalent Mn(1)O6 octahedra,  an edgeedge with one Mn(2)O5 square pyramid, and  an edgeedge with one Mg(1)O5 trigonal bipyramid. The corner-sharing octahedral tilt angles are 77°. In the fourth Mn site, Mn(4) is bonded in a 5-coordinate geometry to one O(1), one O(2), one O(4), one O(7), and one O(8) atom. In the fifth Mn site, Mn(5) is bonded to one O(1), one O(2), one O(3), one O(6), one O(7), and one O(8) atom to form MnO6 octahedra that share  a cornercorner with one Mn(3)O5 square pyramid, corners with three equivalent Mn(2)O5 square pyramids,  a cornercorner with one Mg(1)O5 trigonal bipyramid, edges with two equivalent Mn(1)O6 octahedra,  an edgeedge with one Mn(3)O5 square pyramid, and  an edgeedge with one Mg(1)O5 trigonal bipyramid. There are eight inequivalent O sites. In the first O site, O(1) is bonded in a rectangular see-saw-like geometry to one Mg(1), one Mn(2), one Mn(4), and one Mn(5) atom. In the second O site, O(2) is bonded to one Mn(1), one Mn(3), one Mn(4), and one Mn(5) atom to form distorted OMn4 trigonal pyramids that share  a cornercorner with one O(4)MgMn4 trigonal bipyramid, corners with three equivalent O(7)MgMn3 trigonal pyramids,  an edgeedge with one O(4)MgMn4 trigonal bipyramid, and  an edgeedge with one O(5)MgMn3 trigonal pyramid. In the third O site, O(3) is bonded in a distorted rectangular see-saw-like geometry to one Mn(1), one Mn(2), one Mn(3), and one Mn(5) atom. In the fourth O site, O(4) is bonded to one Mg(1), one Mn(1), one Mn(2), one Mn(3), and one Mn(4) atom to form distorted OMgMn4 trigonal bipyramids that share  a cornercorner with one O(7)MgMn3 trigonal pyramid,  a cornercorner with one O(2)Mn4 trigonal pyramid, corners with two equivalent O(5)MgMn3 trigonal pyramids,  an edgeedge with one O(5)MgMn3 trigonal pyramid,  an edgeedge with one O(7)MgMn3 trigonal pyramid, and  an edgeedge with one O(2)Mn4 trigonal pyramid. In the fifth O site, O(5) is bonded to one Mg(1), one Mn(1), one Mn(2), and one Mn(3) atom to form distorted OMgMn3 trigonal pyramids that share corners with two equivalent O(4)MgMn4 trigonal bipyramids, corners with two equivalent O(7)MgMn3 trigonal pyramids,  an edgeedge with one O(4)MgMn4 trigonal bipyramid, and  an edgeedge with one O(2)Mn4 trigonal pyramid. In the sixth O site, O(6) is bonded in a rectangular see-saw-like geometry to one Mg(1), one Mn(1), one Mn(2), and one Mn(5) atom. In the seventh O site, O(7) is bonded to one Mg(1), one Mn(1), one Mn(4), and one Mn(5) atom to form distorted OMgMn3 trigonal pyramids that share  a cornercorner with one O(4)MgMn4 trigonal bipyramid, corners with two equivalent O(5)MgMn3 trigonal pyramids, corners with three equivalent O(2)Mn4 trigonal pyramids, and  an edgeedge with one O(4)MgMn4 trigonal bipyramid. In the eighth O site, O(8) is bonded in a trigonal non-coplanar geometry to one Mn(3), one Mn(4), and one Mn(5) atom. is represented by the Crystallographic Information File (CIF) [CIF]
data_MgMn5O8
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   6.099
_cell_length_b   7.778
_cell_length_c   6.173
_cell_angle_alpha   108.940
_cell_angle_beta   62.458
_cell_angle_gamma   63.076
_symmetry_Int_Tables_number   1
_cell_volume   170.716
_cell_formula_units_Z   1
loop_
 _symmetry_equiv_pos_site_id
 _symmetry_equiv_pos_as_xyz
  1  'x, y, z'
loop_
 _atom_site_type_symbol
 _atom_site_label
 _atom_site_symmetry_multiplicity
 _atom_site_fract_x
 _atom_site_fract_y
 _atom_site_fract_z
 _atom_site_occupancy
  Mg  Mg0  1  0.656  0.040  0.761  1.0
  Mn  Mn1  1  0.021  0.509  0.483  1.0
  Mn  Mn2  1  0.897  0.071  0.117  1.0
  Mn  Mn3  1  0.336  0.988  0.230  1.0
  Mn  Mn4  1  0.014  0.526  0.979  1.0
  Mn  Mn5  1  0.508  0.512  0.992  1.0
  O  O6  1  0.536  0.285  0.671  1.0
  O  O7  1  0.078  0.319  0.632  1.0
  O  O8  1  0.375  0.758  0.933  1.0
  O  O9  1  0.864  0.796  0.858  1.0
  O  O10  1  0.155  0.216  0.144  1.0
  O  O11  1  0.598  0.289  0.083  1.0
  O  O12  1  0.952  0.701  0.338  1.0
  O  O13  1  0.500  0.740  0.280  1.0
[/CIF]
.