The compound described by NiMn2O4 is Spinel-like structured and crystallizes in the monoclinic Cm space group. There are six inequivalent Mn sites. In the first Mn site, Mn(1) is bonded to one O(4), one O(9), and two equivalent O(6) atoms to form MnO4 tetrahedra that share  a cornercorner with one Ni(4)O6 octahedra, corners with two equivalent Mn(5)O6 octahedra, corners with two equivalent Ni(2)O6 octahedra, corners with three equivalent Ni(3)O6 octahedra, and corners with four equivalent Mn(2)O6 octahedra. The corner-sharing octahedral tilt angles range from 55-63°. In the second Mn site, Mn(2) is bonded to one O(3), one O(5), one O(6), one O(7), one O(8), and one O(9) atom to form MnO6 octahedra that share  a cornercorner with one Mn(4)O4 tetrahedra,  a cornercorner with one Ni(1)O4 tetrahedra, corners with two equivalent Mn(1)O4 tetrahedra, corners with two equivalent Mn(6)O4 tetrahedra,  an edgeedge with one Mn(3)O6 octahedra,  an edgeedge with one Ni(3)O6 octahedra, edges with two equivalent Mn(2)O6 octahedra, and edges with two equivalent Ni(2)O6 octahedra. In the third Mn site, Mn(3) is bonded to one O(12), one O(5), two equivalent O(10), and two equivalent O(3) atoms to form MnO6 octahedra that share corners with three equivalent Mn(6)O4 tetrahedra, corners with three equivalent Ni(1)O4 tetrahedra,  an edgeedge with one Ni(2)O6 octahedra,  an edgeedge with one Ni(4)O6 octahedra, edges with two equivalent Mn(2)O6 octahedra, and edges with two equivalent Mn(5)O6 octahedra. In the fourth Mn site, Mn(4) is bonded to one O(2), one O(8), and two equivalent O(1) atoms to form MnO4 tetrahedra that share  a cornercorner with one Ni(2)O6 octahedra, corners with two equivalent Mn(2)O6 octahedra, corners with two equivalent Ni(4)O6 octahedra, corners with three equivalent Ni(3)O6 octahedra, and corners with four equivalent Mn(5)O6 octahedra. The corner-sharing octahedral tilt angles range from 56-63°. In the fifth Mn site, Mn(5) is bonded to one O(1), one O(10), one O(11), one O(12), one O(2), and one O(4) atom to form MnO6 octahedra that share  a cornercorner with one Mn(1)O4 tetrahedra,  a cornercorner with one Mn(6)O4 tetrahedra, corners with two equivalent Mn(4)O4 tetrahedra, corners with two equivalent Ni(1)O4 tetrahedra,  an edgeedge with one Mn(3)O6 octahedra,  an edgeedge with one Ni(3)O6 octahedra, edges with two equivalent Mn(5)O6 octahedra, and edges with two equivalent Ni(4)O6 octahedra. In the sixth Mn site, Mn(6) is bonded to one O(11), one O(5), and two equivalent O(3) atoms to form MnO4 tetrahedra that share  a cornercorner with one Ni(4)O6 octahedra, corners with two equivalent Mn(5)O6 octahedra, corners with two equivalent Ni(2)O6 octahedra, corners with three equivalent Mn(3)O6 octahedra, and corners with four equivalent Mn(2)O6 octahedra. The corner-sharing octahedral tilt angles range from 57-62°. There are four inequivalent Ni sites. In the first Ni site, Ni(1) is bonded to one O(12), one O(7), and two equivalent O(10) atoms to form NiO4 tetrahedra that share  a cornercorner with one Ni(2)O6 octahedra, corners with two equivalent Mn(2)O6 octahedra, corners with two equivalent Ni(4)O6 octahedra, corners with three equivalent Mn(3)O6 octahedra, and corners with four equivalent Mn(5)O6 octahedra. The corner-sharing octahedral tilt angles range from 53-63°. In the second Ni site, Ni(2) is bonded to one O(7), one O(8), two equivalent O(3), and two equivalent O(6) atoms to form NiO6 octahedra that share  a cornercorner with one Mn(4)O4 tetrahedra,  a cornercorner with one Ni(1)O4 tetrahedra, corners with two equivalent Mn(1)O4 tetrahedra, corners with two equivalent Mn(6)O4 tetrahedra,  an edgeedge with one Mn(3)O6 octahedra,  an edgeedge with one Ni(3)O6 octahedra, and edges with four equivalent Mn(2)O6 octahedra. In the third Ni site, Ni(3) is bonded to one O(2), one O(9), two equivalent O(1), and two equivalent O(6) atoms to form NiO6 octahedra that share corners with three equivalent Mn(1)O4 tetrahedra, corners with three equivalent Mn(4)O4 tetrahedra,  an edgeedge with one Ni(2)O6 octahedra,  an edgeedge with one Ni(4)O6 octahedra, edges with two equivalent Mn(2)O6 octahedra, and edges with two equivalent Mn(5)O6 octahedra. In the fourth Ni site, Ni(4) is bonded to one O(11), one O(4), two equivalent O(1), and two equivalent O(10) atoms to form NiO6 octahedra that share  a cornercorner with one Mn(1)O4 tetrahedra,  a cornercorner with one Mn(6)O4 tetrahedra, corners with two equivalent Mn(4)O4 tetrahedra, corners with two equivalent Ni(1)O4 tetrahedra,  an edgeedge with one Mn(3)O6 octahedra,  an edgeedge with one Ni(3)O6 octahedra, and edges with four equivalent Mn(5)O6 octahedra. There are twelve inequivalent O sites. In the first O site, O(1) is bonded to one Mn(4), one Mn(5), one Ni(3), and one Ni(4) atom to form distorted OMn2Ni2 trigonal pyramids that share corners with two equivalent O(4)Mn3Ni tetrahedra,  a cornercorner with one O(1)Mn2Ni2 trigonal pyramid,  a cornercorner with one O(8)Mn3Ni trigonal pyramid, and  an edgeedge with one O(1)Mn2Ni2 trigonal pyramid. In the second O site, O(2) is bonded in a rectangular see-saw-like geometry to one Mn(4), two equivalent Mn(5), and one Ni(3) atom. In the third O site, O(3) is bonded to one Mn(2), one Mn(3), one Mn(6), and one Ni(2) atom to form distorted OMn3Ni trigonal pyramids that share  a cornercorner with one O(3)Mn3Ni trigonal pyramid,  a cornercorner with one O(5)Mn4 trigonal pyramid,  an edgeedge with one O(3)Mn3Ni trigonal pyramid,  an edgeedge with one O(8)Mn3Ni trigonal pyramid, and  an edgeedge with one O(5)Mn4 trigonal pyramid. In the fourth O site, O(4) is bonded to one Mn(1), two equivalent Mn(5), and one Ni(4) atom to form distorted corner-sharing OMn3Ni tetrahedra. In the fifth O site, O(5) is bonded to one Mn(3), one Mn(6), and two equivalent Mn(2) atoms to form a mixture of distorted corner and edge-sharing OMn4 trigonal pyramids. In the sixth O site, O(6) is bonded in a distorted rectangular see-saw-like geometry to one Mn(1), one Mn(2), one Ni(2), and one Ni(3) atom. In the seventh O site, O(7) is bonded in a rectangular see-saw-like geometry to two equivalent Mn(2), one Ni(1), and one Ni(2) atom. In the eighth O site, O(8) is bonded to one Mn(4), two equivalent Mn(2), and one Ni(2) atom to form distorted OMn3Ni trigonal pyramids that share corners with two equivalent O(1)Mn2Ni2 trigonal pyramids,  an edgeedge with one O(5)Mn4 trigonal pyramid, and edges with two equivalent O(3)Mn3Ni trigonal pyramids. In the ninth O site, O(9) is bonded in a rectangular see-saw-like geometry to one Mn(1), two equivalent Mn(2), and one Ni(3) atom. In the tenth O site, O(10) is bonded in a distorted rectangular see-saw-like geometry to one Mn(3), one Mn(5), one Ni(1), and one Ni(4) atom. In the eleventh O site, O(11) is bonded in a distorted rectangular see-saw-like geometry to one Mn(6), two equivalent Mn(5), and one Ni(4) atom. In the twelfth O site, O(12) is bonded in a rectangular see-saw-like geometry to one Mn(3), two equivalent Mn(5), and one Ni(1) atom. is represented by the CIF card [CIF]
data_Mn2NiO4
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   6.001
_cell_length_b   6.001
_cell_length_c   10.331
_cell_angle_alpha   73.920
_cell_angle_beta   73.920
_cell_angle_gamma   61.022
_symmetry_Int_Tables_number   1
_cell_volume   308.216
_cell_formula_units_Z   4
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
  Mn  Mn0  1  0.431  0.431  0.688  1.0
  Mn  Mn1  1  0.506  0.999  0.499  1.0
  Mn  Mn2  1  0.248  0.248  0.248  1.0
  Mn  Mn3  1  0.999  0.506  0.499  1.0
  Mn  Mn4  1  0.070  0.070  0.813  1.0
  Mn  Mn5  1  0.996  0.501  0.000  1.0
  Mn  Mn6  1  0.501  0.996  0.000  1.0
  Mn  Mn7  1  0.567  0.567  0.314  1.0
  Ni  Ni8  1  0.928  0.928  0.184  1.0
  Ni  Ni9  1  0.000  0.000  0.499  1.0
  Ni  Ni10  1  0.751  0.751  0.751  1.0
  Ni  Ni11  1  0.501  0.501  0.000  1.0
  O  O12  1  0.865  0.409  0.887  1.0
  O  O13  1  0.862  0.862  0.887  1.0
  O  O14  1  0.364  0.919  0.377  1.0
  O  O15  1  0.357  0.357  0.898  1.0
  O  O16  1  0.409  0.865  0.887  1.0
  O  O17  1  0.358  0.358  0.380  1.0
  O  O18  1  0.096  0.637  0.612  1.0
  O  O19  1  0.861  0.861  0.389  1.0
  O  O20  1  0.145  0.145  0.603  1.0
  O  O21  1  0.919  0.364  0.377  1.0
  O  O22  1  0.639  0.639  0.610  1.0
  O  O23  1  0.580  0.138  0.126  1.0
  O  O24  1  0.640  0.640  0.107  1.0
  O  O25  1  0.637  0.096  0.612  1.0
  O  O26  1  0.131  0.131  0.126  1.0
  O  O27  1  0.138  0.580  0.126  1.0
[/CIF]
.
The compound described by NiMn2O4 is Spinel-like structured and crystallizes in the monoclinic Cm space group. There are six inequivalent Mn sites. In the first Mn site, Mn(1) is bonded to one O(4), one O(9), and two equivalent O(6) atoms to form MnO4 tetrahedra that share  a cornercorner with one Ni(4)O6 octahedra, corners with two equivalent Mn(5)O6 octahedra, corners with two equivalent Ni(2)O6 octahedra, corners with three equivalent Ni(3)O6 octahedra, and corners with four equivalent Mn(2)O6 octahedra. The corner-sharing octahedral tilt angles range from 55-63°. In the second Mn site, Mn(2) is bonded to one O(3), one O(5), one O(6), one O(7), one O(8), and one O(9) atom to form MnO6 octahedra that share  a cornercorner with one Mn(4)O4 tetrahedra,  a cornercorner with one Ni(1)O4 tetrahedra, corners with two equivalent Mn(1)O4 tetrahedra, corners with two equivalent Mn(6)O4 tetrahedra,  an edgeedge with one Mn(3)O6 octahedra,  an edgeedge with one Ni(3)O6 octahedra, edges with two equivalent Mn(2)O6 octahedra, and edges with two equivalent Ni(2)O6 octahedra. In the third Mn site, Mn(3) is bonded to one O(12), one O(5), two equivalent O(10), and two equivalent O(3) atoms to form MnO6 octahedra that share corners with three equivalent Mn(6)O4 tetrahedra, corners with three equivalent Ni(1)O4 tetrahedra,  an edgeedge with one Ni(2)O6 octahedra,  an edgeedge with one Ni(4)O6 octahedra, edges with two equivalent Mn(2)O6 octahedra, and edges with two equivalent Mn(5)O6 octahedra. In the fourth Mn site, Mn(4) is bonded to one O(2), one O(8), and two equivalent O(1) atoms to form MnO4 tetrahedra that share  a cornercorner with one Ni(2)O6 octahedra, corners with two equivalent Mn(2)O6 octahedra, corners with two equivalent Ni(4)O6 octahedra, corners with three equivalent Ni(3)O6 octahedra, and corners with four equivalent Mn(5)O6 octahedra. The corner-sharing octahedral tilt angles range from 56-63°. In the fifth Mn site, Mn(5) is bonded to one O(1), one O(10), one O(11), one O(12), one O(2), and one O(4) atom to form MnO6 octahedra that share  a cornercorner with one Mn(1)O4 tetrahedra,  a cornercorner with one Mn(6)O4 tetrahedra, corners with two equivalent Mn(4)O4 tetrahedra, corners with two equivalent Ni(1)O4 tetrahedra,  an edgeedge with one Mn(3)O6 octahedra,  an edgeedge with one Ni(3)O6 octahedra, edges with two equivalent Mn(5)O6 octahedra, and edges with two equivalent Ni(4)O6 octahedra. In the sixth Mn site, Mn(6) is bonded to one O(11), one O(5), and two equivalent O(3) atoms to form MnO4 tetrahedra that share  a cornercorner with one Ni(4)O6 octahedra, corners with two equivalent Mn(5)O6 octahedra, corners with two equivalent Ni(2)O6 octahedra, corners with three equivalent Mn(3)O6 octahedra, and corners with four equivalent Mn(2)O6 octahedra. The corner-sharing octahedral tilt angles range from 57-62°. There are four inequivalent Ni sites. In the first Ni site, Ni(1) is bonded to one O(12), one O(7), and two equivalent O(10) atoms to form NiO4 tetrahedra that share  a cornercorner with one Ni(2)O6 octahedra, corners with two equivalent Mn(2)O6 octahedra, corners with two equivalent Ni(4)O6 octahedra, corners with three equivalent Mn(3)O6 octahedra, and corners with four equivalent Mn(5)O6 octahedra. The corner-sharing octahedral tilt angles range from 53-63°. In the second Ni site, Ni(2) is bonded to one O(7), one O(8), two equivalent O(3), and two equivalent O(6) atoms to form NiO6 octahedra that share  a cornercorner with one Mn(4)O4 tetrahedra,  a cornercorner with one Ni(1)O4 tetrahedra, corners with two equivalent Mn(1)O4 tetrahedra, corners with two equivalent Mn(6)O4 tetrahedra,  an edgeedge with one Mn(3)O6 octahedra,  an edgeedge with one Ni(3)O6 octahedra, and edges with four equivalent Mn(2)O6 octahedra. In the third Ni site, Ni(3) is bonded to one O(2), one O(9), two equivalent O(1), and two equivalent O(6) atoms to form NiO6 octahedra that share corners with three equivalent Mn(1)O4 tetrahedra, corners with three equivalent Mn(4)O4 tetrahedra,  an edgeedge with one Ni(2)O6 octahedra,  an edgeedge with one Ni(4)O6 octahedra, edges with two equivalent Mn(2)O6 octahedra, and edges with two equivalent Mn(5)O6 octahedra. In the fourth Ni site, Ni(4) is bonded to one O(11), one O(4), two equivalent O(1), and two equivalent O(10) atoms to form NiO6 octahedra that share  a cornercorner with one Mn(1)O4 tetrahedra,  a cornercorner with one Mn(6)O4 tetrahedra, corners with two equivalent Mn(4)O4 tetrahedra, corners with two equivalent Ni(1)O4 tetrahedra,  an edgeedge with one Mn(3)O6 octahedra,  an edgeedge with one Ni(3)O6 octahedra, and edges with four equivalent Mn(5)O6 octahedra. There are twelve inequivalent O sites. In the first O site, O(1) is bonded to one Mn(4), one Mn(5), one Ni(3), and one Ni(4) atom to form distorted OMn2Ni2 trigonal pyramids that share corners with two equivalent O(4)Mn3Ni tetrahedra,  a cornercorner with one O(1)Mn2Ni2 trigonal pyramid,  a cornercorner with one O(8)Mn3Ni trigonal pyramid, and  an edgeedge with one O(1)Mn2Ni2 trigonal pyramid. In the second O site, O(2) is bonded in a rectangular see-saw-like geometry to one Mn(4), two equivalent Mn(5), and one Ni(3) atom. In the third O site, O(3) is bonded to one Mn(2), one Mn(3), one Mn(6), and one Ni(2) atom to form distorted OMn3Ni trigonal pyramids that share  a cornercorner with one O(3)Mn3Ni trigonal pyramid,  a cornercorner with one O(5)Mn4 trigonal pyramid,  an edgeedge with one O(3)Mn3Ni trigonal pyramid,  an edgeedge with one O(8)Mn3Ni trigonal pyramid, and  an edgeedge with one O(5)Mn4 trigonal pyramid. In the fourth O site, O(4) is bonded to one Mn(1), two equivalent Mn(5), and one Ni(4) atom to form distorted corner-sharing OMn3Ni tetrahedra. In the fifth O site, O(5) is bonded to one Mn(3), one Mn(6), and two equivalent Mn(2) atoms to form a mixture of distorted corner and edge-sharing OMn4 trigonal pyramids. In the sixth O site, O(6) is bonded in a distorted rectangular see-saw-like geometry to one Mn(1), one Mn(2), one Ni(2), and one Ni(3) atom. In the seventh O site, O(7) is bonded in a rectangular see-saw-like geometry to two equivalent Mn(2), one Ni(1), and one Ni(2) atom. In the eighth O site, O(8) is bonded to one Mn(4), two equivalent Mn(2), and one Ni(2) atom to form distorted OMn3Ni trigonal pyramids that share corners with two equivalent O(1)Mn2Ni2 trigonal pyramids,  an edgeedge with one O(5)Mn4 trigonal pyramid, and edges with two equivalent O(3)Mn3Ni trigonal pyramids. In the ninth O site, O(9) is bonded in a rectangular see-saw-like geometry to one Mn(1), two equivalent Mn(2), and one Ni(3) atom. In the tenth O site, O(10) is bonded in a distorted rectangular see-saw-like geometry to one Mn(3), one Mn(5), one Ni(1), and one Ni(4) atom. In the eleventh O site, O(11) is bonded in a distorted rectangular see-saw-like geometry to one Mn(6), two equivalent Mn(5), and one Ni(4) atom. In the twelfth O site, O(12) is bonded in a rectangular see-saw-like geometry to one Mn(3), two equivalent Mn(5), and one Ni(1) atom. is represented by the CIF card [CIF]
data_Mn2NiO4
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   6.001
_cell_length_b   6.001
_cell_length_c   10.331
_cell_angle_alpha   73.920
_cell_angle_beta   73.920
_cell_angle_gamma   61.022
_symmetry_Int_Tables_number   1
_cell_volume   308.216
_cell_formula_units_Z   4
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
  Mn  Mn0  1  0.431  0.431  0.688  1.0
  Mn  Mn1  1  0.506  0.999  0.499  1.0
  Mn  Mn2  1  0.248  0.248  0.248  1.0
  Mn  Mn3  1  0.999  0.506  0.499  1.0
  Mn  Mn4  1  0.070  0.070  0.813  1.0
  Mn  Mn5  1  0.996  0.501  0.000  1.0
  Mn  Mn6  1  0.501  0.996  0.000  1.0
  Mn  Mn7  1  0.567  0.567  0.314  1.0
  Ni  Ni8  1  0.928  0.928  0.184  1.0
  Ni  Ni9  1  0.000  0.000  0.499  1.0
  Ni  Ni10  1  0.751  0.751  0.751  1.0
  Ni  Ni11  1  0.501  0.501  0.000  1.0
  O  O12  1  0.865  0.409  0.887  1.0
  O  O13  1  0.862  0.862  0.887  1.0
  O  O14  1  0.364  0.919  0.377  1.0
  O  O15  1  0.357  0.357  0.898  1.0
  O  O16  1  0.409  0.865  0.887  1.0
  O  O17  1  0.358  0.358  0.380  1.0
  O  O18  1  0.096  0.637  0.612  1.0
  O  O19  1  0.861  0.861  0.389  1.0
  O  O20  1  0.145  0.145  0.603  1.0
  O  O21  1  0.919  0.364  0.377  1.0
  O  O22  1  0.639  0.639  0.610  1.0
  O  O23  1  0.580  0.138  0.126  1.0
  O  O24  1  0.640  0.640  0.107  1.0
  O  O25  1  0.637  0.096  0.612  1.0
  O  O26  1  0.131  0.131  0.126  1.0
  O  O27  1  0.138  0.580  0.126  1.0
[/CIF]
.