The crystal structure described by MgTm4Sm4O12 crystallizes in the monoclinic Pm space group. Mg(1) is bonded to one O(4), one O(8), and two equivalent O(7) atoms to form MgO4 tetrahedra that share corners with four equivalent Tm(1)O6 octahedra and edges with two equivalent Tm(2)O6 octahedra. The corner-sharing octahedral tilt angles range from 30-66°. There are two inequivalent Tm sites. In the first Tm site, Tm(1) 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 TmO6 octahedra that share corners with two equivalent Tm(1)O6 octahedra, corners with four equivalent Tm(2)O6 octahedra, and corners with two equivalent Mg(1)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 35-52°. In the second Tm site, Tm(2) 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 TmO6 octahedra that share corners with two equivalent Tm(2)O6 octahedra, corners with four equivalent Tm(1)O6 octahedra, and  an edgeedge with one Mg(1)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 35-55°. There are four inequivalent Sm sites. In the first Sm site, Sm(1) is bonded in a 6-coordinate geometry to one O(4), one O(8), two equivalent O(3), and two equivalent O(7) atoms. In the second Sm site, Sm(2) is bonded in a 8-coordinate geometry to one O(1), one O(5), two equivalent O(2), two equivalent O(3), and two equivalent O(6) atoms. In the third Sm site, Sm(3) is bonded in a 6-coordinate geometry to one O(4), one O(8), two equivalent O(3), and two equivalent O(7) atoms. In the fourth Sm site, Sm(4) is bonded in a 6-coordinate geometry to one O(1), one O(5), two equivalent O(2), two equivalent O(6), and two equivalent O(7) atoms. There are eight inequivalent O sites. In the first O site, O(1) is bonded in a distorted trigonal pyramidal geometry to two equivalent Tm(1), one Sm(2), and one Sm(4) atom. In the second O site, O(2) is bonded in a 4-coordinate geometry to one Tm(1), one Tm(2), one Sm(2), and one Sm(4) atom. In the third O site, O(3) is bonded in a 5-coordinate geometry to one Tm(1), one Tm(2), one Sm(1), one Sm(2), and one Sm(3) atom. In the fourth O site, O(4) is bonded in a 5-coordinate geometry to one Mg(1), two equivalent Tm(2), one Sm(1), and one Sm(3) atom. In the fifth O site, O(5) is bonded in a distorted see-saw-like geometry to two equivalent Tm(2), one Sm(2), and one Sm(4) atom. In the sixth O site, O(6) is bonded in a 4-coordinate geometry to one Tm(1), one Tm(2), one Sm(2), and one Sm(4) atom. In the seventh O site, O(7) is bonded in a 6-coordinate geometry to one Mg(1), one Tm(1), one Tm(2), one Sm(1), one Sm(3), and one Sm(4) atom. In the eighth O site, O(8) is bonded in a 5-coordinate geometry to one Mg(1), two equivalent Tm(1), one Sm(1), and one Sm(3) atom. is represented by the CIF file [CIF]
data_Sm4Tm4MgO12
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   6.147
_cell_length_b   8.449
_cell_length_c   5.766
_cell_angle_alpha   90.000
_cell_angle_beta   88.439
_cell_angle_gamma   90.000
_symmetry_Int_Tables_number   1
_cell_volume   299.310
_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
  Sm  Sm0  1  0.155  0.250  0.937  1.0
  Sm  Sm1  1  0.426  0.750  0.477  1.0
  Sm  Sm2  1  0.558  0.250  0.562  1.0
  Sm  Sm3  1  0.938  0.750  0.029  1.0
  Tm  Tm4  1  0.989  1.000  0.500  1.0
  Tm  Tm5  1  0.989  0.500  0.500  1.0
  Tm  Tm6  1  0.487  0.977  0.993  1.0
  Tm  Tm7  1  0.487  0.523  0.993  1.0
  Mg  Mg8  1  0.736  0.250  0.070  1.0
  O  O9  1  0.050  0.750  0.638  1.0
  O  O10  1  0.190  0.579  0.190  1.0
  O  O11  1  0.190  0.921  0.190  1.0
  O  O12  1  0.305  0.455  0.672  1.0
  O  O13  1  0.305  0.045  0.672  1.0
  O  O14  1  0.437  0.250  0.198  1.0
  O  O15  1  0.570  0.750  0.844  1.0
  O  O16  1  0.694  0.921  0.295  1.0
  O  O17  1  0.694  0.579  0.295  1.0
  O  O18  1  0.808  0.078  0.830  1.0
  O  O19  1  0.808  0.422  0.830  1.0
  O  O20  1  0.922  0.250  0.348  1.0
[/CIF]
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The crystal structure described by MgTm4Sm4O12 crystallizes in the monoclinic Pm space group. Mg(1) is bonded to one O(4), one O(8), and two equivalent O(7) atoms to form MgO4 tetrahedra that share corners with four equivalent Tm(1)O6 octahedra and edges with two equivalent Tm(2)O6 octahedra. The corner-sharing octahedral tilt angles range from 30-66°. There are two inequivalent Tm sites. In the first Tm site, Tm(1) 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 TmO6 octahedra that share corners with two equivalent Tm(1)O6 octahedra, corners with four equivalent Tm(2)O6 octahedra, and corners with two equivalent Mg(1)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 35-52°. In the second Tm site, Tm(2) 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 TmO6 octahedra that share corners with two equivalent Tm(2)O6 octahedra, corners with four equivalent Tm(1)O6 octahedra, and  an edgeedge with one Mg(1)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 35-55°. There are four inequivalent Sm sites. In the first Sm site, Sm(1) is bonded in a 6-coordinate geometry to one O(4), one O(8), two equivalent O(3), and two equivalent O(7) atoms. In the second Sm site, Sm(2) is bonded in a 8-coordinate geometry to one O(1), one O(5), two equivalent O(2), two equivalent O(3), and two equivalent O(6) atoms. In the third Sm site, Sm(3) is bonded in a 6-coordinate geometry to one O(4), one O(8), two equivalent O(3), and two equivalent O(7) atoms. In the fourth Sm site, Sm(4) is bonded in a 6-coordinate geometry to one O(1), one O(5), two equivalent O(2), two equivalent O(6), and two equivalent O(7) atoms. There are eight inequivalent O sites. In the first O site, O(1) is bonded in a distorted trigonal pyramidal geometry to two equivalent Tm(1), one Sm(2), and one Sm(4) atom. In the second O site, O(2) is bonded in a 4-coordinate geometry to one Tm(1), one Tm(2), one Sm(2), and one Sm(4) atom. In the third O site, O(3) is bonded in a 5-coordinate geometry to one Tm(1), one Tm(2), one Sm(1), one Sm(2), and one Sm(3) atom. In the fourth O site, O(4) is bonded in a 5-coordinate geometry to one Mg(1), two equivalent Tm(2), one Sm(1), and one Sm(3) atom. In the fifth O site, O(5) is bonded in a distorted see-saw-like geometry to two equivalent Tm(2), one Sm(2), and one Sm(4) atom. In the sixth O site, O(6) is bonded in a 4-coordinate geometry to one Tm(1), one Tm(2), one Sm(2), and one Sm(4) atom. In the seventh O site, O(7) is bonded in a 6-coordinate geometry to one Mg(1), one Tm(1), one Tm(2), one Sm(1), one Sm(3), and one Sm(4) atom. In the eighth O site, O(8) is bonded in a 5-coordinate geometry to one Mg(1), two equivalent Tm(1), one Sm(1), and one Sm(3) atom. is represented by the CIF file [CIF]
data_Sm4Tm4MgO12
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   6.147
_cell_length_b   8.449
_cell_length_c   5.766
_cell_angle_alpha   90.000
_cell_angle_beta   88.439
_cell_angle_gamma   90.000
_symmetry_Int_Tables_number   1
_cell_volume   299.310
_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
  Sm  Sm0  1  0.155  0.250  0.937  1.0
  Sm  Sm1  1  0.426  0.750  0.477  1.0
  Sm  Sm2  1  0.558  0.250  0.562  1.0
  Sm  Sm3  1  0.938  0.750  0.029  1.0
  Tm  Tm4  1  0.989  1.000  0.500  1.0
  Tm  Tm5  1  0.989  0.500  0.500  1.0
  Tm  Tm6  1  0.487  0.977  0.993  1.0
  Tm  Tm7  1  0.487  0.523  0.993  1.0
  Mg  Mg8  1  0.736  0.250  0.070  1.0
  O  O9  1  0.050  0.750  0.638  1.0
  O  O10  1  0.190  0.579  0.190  1.0
  O  O11  1  0.190  0.921  0.190  1.0
  O  O12  1  0.305  0.455  0.672  1.0
  O  O13  1  0.305  0.045  0.672  1.0
  O  O14  1  0.437  0.250  0.198  1.0
  O  O15  1  0.570  0.750  0.844  1.0
  O  O16  1  0.694  0.921  0.295  1.0
  O  O17  1  0.694  0.579  0.295  1.0
  O  O18  1  0.808  0.078  0.830  1.0
  O  O19  1  0.808  0.422  0.830  1.0
  O  O20  1  0.922  0.250  0.348  1.0
[/CIF]
.