data_SrCa2Mg
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   12.24
_cell_length_b   12.24
_cell_length_c   12.24
_cell_angle_alpha   18.59
_cell_angle_beta   18.59
_cell_angle_gamma   18.59
_symmetry_Int_Tables_number   1
_chemical_formula_structural   SrCa2Mg
_chemical_formula_sum   'Sr1 Ca2 Mg1'
_cell_volume   162.55
_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  Sr3  1  0.0  0.0  0.03  1.0
  Ca  Ca0  1  0.0  0.0  0.68  1.0
  Ca  Ca1  1  0.0  0.0  0.38  1.0
  Mg  Mg2  1  0.0  0.0  0.0  1.0

data_SrCa2Mg
_symmetry_space_group_name_H-M   Cm
_cell_length_a   6.84
_cell_length_b   3.95
_cell_length_c   12.24
_cell_angle_alpha   90.0
_cell_angle_beta   100.75
_cell_angle_gamma   90.0
_symmetry_Int_Tables_number   8
_chemical_formula_structural   SrCa2Mg
_chemical_formula_sum   'Sr2 Ca4 Mg2'
_cell_volume   325.1
_cell_formula_units_Z   2
loop_
 _symmetry_equiv_pos_site_id
 _symmetry_equiv_pos_as_xyz
  1  'x, y, z'
  2  'x, -y, z'
  3  'x+1/2, y+1/2, z'
  4  'x+1/2, -y+1/2, 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  2  0.0  0.0  0.97  1.0
  Ca  Ca1  2  0.0  0.0  0.32  1.0
  Ca  Ca2  2  0.0  0.0  0.62  1.0
  Mg  Mg3  2  0.0  0.0  0.0  1.0

Sr Ca Ca Mg
Sr Ca Ca Mg 0 3 o o o 0 1 o o - 0 2 o o o 1 1 o + - 1 1 + - o 1 1 + o - 1 2 o o o 1 3 o o + 2 2 o + - 2 2 + - o 2 2 + o - 
SrCa2Mg crystallizes in the monoclinic Cm space group. Sr(1) is bonded in a single-bond geometry to one Ca(2) and one Mg(1) atom. The Sr(1)-Ca(2) bond length is 4.31 Å. The Sr(1)-Mg(1) bond length is 0.38 Å. There are two inequivalent Ca sites. In the first Ca site, Ca(1) is bonded to one Ca(2), six equivalent Ca(1), and one Mg(1) atom to form distorted CaCa7Mg hexagonal bipyramids that share corners with six equivalent Ca(1)Ca7Mg hexagonal bipyramids, edges with six equivalent Ca(2)SrCa7 hexagonal bipyramids, and edges with twelve equivalent Ca(1)Ca7Mg hexagonal bipyramids. The Ca(1)-Ca(2) bond length is 3.61 Å. All Ca(1)-Ca(1) bond lengths are 3.95 Å. The Ca(1)-Mg(1) bond length is 3.93 Å. In the second Ca site, Ca(2) is bonded to one Sr(1), one Ca(1), and six equivalent Ca(2) atoms to form CaSrCa7 hexagonal bipyramids that share corners with six equivalent Ca(2)SrCa7 hexagonal bipyramids, edges with six equivalent Ca(1)Ca7Mg hexagonal bipyramids, and edges with twelve equivalent Ca(2)SrCa7 hexagonal bipyramids. All Ca(2)-Ca(2) bond lengths are 3.95 Å. Mg(1) is bonded in a single-bond geometry to one Sr(1) and one Ca(1) atom.