The structure described by SrMgNiO3 crystallizes in the monoclinic Cm space group. Sr(1) is bonded in a body-centered cubic geometry to two equivalent O(1), two equivalent O(3), and four equivalent O(2) atoms. Mg(1) is bonded to one O(2), two equivalent O(1), and two equivalent O(3) atoms to form MgO5 trigonal bipyramids that share  a cornercorner with one Ni(1)O5 trigonal bipyramid, corners with four equivalent Mg(1)O5 trigonal bipyramids, and edges with four equivalent Ni(1)O5 trigonal bipyramids. Ni(1) is bonded to one O(2), two equivalent O(1), and two equivalent O(3) atoms to form NiO5 trigonal bipyramids that share  a cornercorner with one Mg(1)O5 trigonal bipyramid, corners with four equivalent Ni(1)O5 trigonal bipyramids, and edges with four equivalent Mg(1)O5 trigonal bipyramids. There are three inequivalent O sites. In the first O site, O(1) is bonded to two equivalent Sr(1), two equivalent Mg(1), and two equivalent Ni(1) atoms to form OSr2Mg2Ni2 octahedra that share corners with two equivalent O(1)Sr2Mg2Ni2 octahedra, corners with two equivalent O(3)Sr2Mg2Ni2 octahedra, corners with six equivalent O(2)Sr4MgNi octahedra, edges with two equivalent O(1)Sr2Mg2Ni2 octahedra, edges with five equivalent O(3)Sr2Mg2Ni2 octahedra, and faces with two equivalent O(2)Sr4MgNi octahedra. The corner-sharing octahedral tilt angles range from 0-68°. In the second O site, O(2) is bonded to four equivalent Sr(1), one Mg(1), and one Ni(1) atom to form distorted OSr4MgNi octahedra that share corners with four equivalent O(2)Sr4MgNi octahedra, corners with six equivalent O(1)Sr2Mg2Ni2 octahedra, corners with six equivalent O(3)Sr2Mg2Ni2 octahedra, edges with four equivalent O(2)Sr4MgNi octahedra, faces with two equivalent O(1)Sr2Mg2Ni2 octahedra, and faces with two equivalent O(3)Sr2Mg2Ni2 octahedra. The corner-sharing octahedral tilt angles range from 3-68°. In the third O site, O(3) is bonded to two equivalent Sr(1), two equivalent Mg(1), and two equivalent Ni(1) atoms to form distorted OSr2Mg2Ni2 octahedra that share corners with two equivalent O(1)Sr2Mg2Ni2 octahedra, corners with two equivalent O(3)Sr2Mg2Ni2 octahedra, corners with six equivalent O(2)Sr4MgNi octahedra, edges with two equivalent O(3)Sr2Mg2Ni2 octahedra, edges with five equivalent O(1)Sr2Mg2Ni2 octahedra, and faces with two equivalent O(2)Sr4MgNi octahedra. The corner-sharing octahedral tilt angles range from 0-68°. is represented by the CIF card [CIF]
data_SrMgNiO3
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   5.981
_cell_length_b   5.977
_cell_length_c   3.337
_cell_angle_alpha   73.602
_cell_angle_beta   73.596
_cell_angle_gamma   40.924
_symmetry_Int_Tables_number   1
_cell_volume   74.520
_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
  Sr  Sr0  1  0.872  0.180  0.631  1.0
  Mg  Mg1  1  0.181  0.489  0.327  1.0
  Ni  Ni2  1  0.558  0.865  0.951  1.0
  O  O3  1  0.678  0.985  0.334  1.0
  O  O4  1  0.371  0.679  0.109  1.0
  O  O5  1  0.071  0.379  0.941  1.0
[/CIF]
.
The structure described by SrMgNiO3 crystallizes in the monoclinic Cm space group. Sr(1) is bonded in a body-centered cubic geometry to two equivalent O(1), two equivalent O(3), and four equivalent O(2) atoms. Mg(1) is bonded to one O(2), two equivalent O(1), and two equivalent O(3) atoms to form MgO5 trigonal bipyramids that share  a cornercorner with one Ni(1)O5 trigonal bipyramid, corners with four equivalent Mg(1)O5 trigonal bipyramids, and edges with four equivalent Ni(1)O5 trigonal bipyramids. Ni(1) is bonded to one O(2), two equivalent O(1), and two equivalent O(3) atoms to form NiO5 trigonal bipyramids that share  a cornercorner with one Mg(1)O5 trigonal bipyramid, corners with four equivalent Ni(1)O5 trigonal bipyramids, and edges with four equivalent Mg(1)O5 trigonal bipyramids. There are three inequivalent O sites. In the first O site, O(1) is bonded to two equivalent Sr(1), two equivalent Mg(1), and two equivalent Ni(1) atoms to form OSr2Mg2Ni2 octahedra that share corners with two equivalent O(1)Sr2Mg2Ni2 octahedra, corners with two equivalent O(3)Sr2Mg2Ni2 octahedra, corners with six equivalent O(2)Sr4MgNi octahedra, edges with two equivalent O(1)Sr2Mg2Ni2 octahedra, edges with five equivalent O(3)Sr2Mg2Ni2 octahedra, and faces with two equivalent O(2)Sr4MgNi octahedra. The corner-sharing octahedral tilt angles range from 0-68°. In the second O site, O(2) is bonded to four equivalent Sr(1), one Mg(1), and one Ni(1) atom to form distorted OSr4MgNi octahedra that share corners with four equivalent O(2)Sr4MgNi octahedra, corners with six equivalent O(1)Sr2Mg2Ni2 octahedra, corners with six equivalent O(3)Sr2Mg2Ni2 octahedra, edges with four equivalent O(2)Sr4MgNi octahedra, faces with two equivalent O(1)Sr2Mg2Ni2 octahedra, and faces with two equivalent O(3)Sr2Mg2Ni2 octahedra. The corner-sharing octahedral tilt angles range from 3-68°. In the third O site, O(3) is bonded to two equivalent Sr(1), two equivalent Mg(1), and two equivalent Ni(1) atoms to form distorted OSr2Mg2Ni2 octahedra that share corners with two equivalent O(1)Sr2Mg2Ni2 octahedra, corners with two equivalent O(3)Sr2Mg2Ni2 octahedra, corners with six equivalent O(2)Sr4MgNi octahedra, edges with two equivalent O(3)Sr2Mg2Ni2 octahedra, edges with five equivalent O(1)Sr2Mg2Ni2 octahedra, and faces with two equivalent O(2)Sr4MgNi octahedra. The corner-sharing octahedral tilt angles range from 0-68°. is represented by the CIF card [CIF]
data_SrMgNiO3
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   5.981
_cell_length_b   5.977
_cell_length_c   3.337
_cell_angle_alpha   73.602
_cell_angle_beta   73.596
_cell_angle_gamma   40.924
_symmetry_Int_Tables_number   1
_cell_volume   74.520
_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
  Sr  Sr0  1  0.872  0.180  0.631  1.0
  Mg  Mg1  1  0.181  0.489  0.327  1.0
  Ni  Ni2  1  0.558  0.865  0.951  1.0
  O  O3  1  0.678  0.985  0.334  1.0
  O  O4  1  0.371  0.679  0.109  1.0
  O  O5  1  0.071  0.379  0.941  1.0
[/CIF]
.