The material structure described by MgSc4(Si2O7)2 crystallizes in the trigonal R3m space group. Mg(1) is bonded in a 7-coordinate geometry to one O(5), three equivalent O(3), and three equivalent O(4) atoms. There are two inequivalent Sc sites. In the first Sc site, Sc(1) is bonded in a 7-coordinate geometry to one O(1), one O(5), one O(6), two equivalent O(2), and two equivalent O(3) atoms. In the second Sc site, Sc(2) is bonded to one O(5), one O(6), three equivalent O(1), and three equivalent O(4) atoms to form distorted ScO8 hexagonal bipyramids that share edges with six equivalent Si(1)O6 octahedra. There are two inequivalent Si sites. In the first Si site, Si(1) is bonded to one O(2), one O(3), two equivalent O(1), and two equivalent O(4) atoms to form SiO6 octahedra that share corners with two equivalent Si(2)O6 octahedra, corners with four equivalent Si(1)O6 octahedra, and edges with two equivalent Sc(2)O8 hexagonal bipyramids. The corner-sharing octahedral tilt angles range from 40-49°. In the second Si site, Si(2) is bonded to three equivalent O(2) and three equivalent O(3) atoms to form corner-sharing SiO6 octahedra. The corner-sharing octahedral tilt angles range from 42-49°. There are six inequivalent O sites. In the first O site, O(4) is bonded in a 4-coordinate geometry to one Mg(1), one Sc(2), and two equivalent Si(1) atoms. In the second O site, O(5) is bonded to one Mg(1), one Sc(2), and three equivalent Sc(1) atoms to form a mixture of distorted edge and corner-sharing OMgSc4 trigonal bipyramids. In the third O site, O(6) is bonded in a rectangular see-saw-like geometry to one Sc(2) and three equivalent Sc(1) atoms. In the fourth O site, O(1) is bonded to one Sc(1), one Sc(2), and two equivalent Si(1) atoms to form distorted OSc2Si2 trigonal pyramids that share corners with four equivalent O(1)Sc2Si2 trigonal pyramids, edges with two equivalent O(2)Sc2Si2 tetrahedra, and  an edgeedge with one O(5)MgSc4 trigonal bipyramid. In the fifth O site, O(2) is bonded to two equivalent Sc(1), one Si(1), and one Si(2) atom to form distorted OSc2Si2 tetrahedra that share corners with four equivalent O(2)Sc2Si2 tetrahedra, corners with two equivalent O(5)MgSc4 trigonal bipyramids, and edges with two equivalent O(1)Sc2Si2 trigonal pyramids. In the sixth O site, O(3) is bonded in a 5-coordinate geometry to one Mg(1), two equivalent Sc(1), one Si(1), and one Si(2) atom. is represented by the Crystallographic Information File (CIF) [CIF]
data_MgSc4(Si2O7)2
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   6.908
_cell_length_b   6.908
_cell_length_c   6.908
_cell_angle_alpha   57.370
_cell_angle_beta   57.370
_cell_angle_gamma   57.370
_symmetry_Int_Tables_number   1
_cell_volume   218.972
_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  0.238  0.238  0.238  1.0
  Sc  Sc1  1  0.961  0.526  0.961  1.0
  Sc  Sc2  1  0.526  0.961  0.961  1.0
  Sc  Sc3  1  0.961  0.961  0.526  1.0
  Sc  Sc4  1  0.003  0.003  0.003  1.0
  Si  Si5  1  0.506  0.998  0.506  1.0
  Si  Si6  1  0.998  0.506  0.506  1.0
  Si  Si7  1  0.506  0.506  0.998  1.0
  Si  Si8  1  0.505  0.505  0.505  1.0
  O  O9  1  0.423  0.820  0.820  1.0
  O  O10  1  0.175  0.576  0.576  1.0
  O  O11  1  0.820  0.423  0.820  1.0
  O  O12  1  0.820  0.820  0.423  1.0
  O  O13  1  0.425  0.425  0.834  1.0
  O  O14  1  0.425  0.834  0.425  1.0
  O  O15  1  0.188  0.575  0.188  1.0
  O  O16  1  0.576  0.175  0.576  1.0
  O  O17  1  0.124  0.124  0.124  1.0
  O  O18  1  0.887  0.887  0.887  1.0
  O  O19  1  0.834  0.425  0.425  1.0
  O  O20  1  0.576  0.576  0.175  1.0
  O  O21  1  0.188  0.188  0.575  1.0
  O  O22  1  0.575  0.188  0.188  1.0
[/CIF]
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The material structure described by MgSc4(Si2O7)2 crystallizes in the trigonal R3m space group. Mg(1) is bonded in a 7-coordinate geometry to one O(5), three equivalent O(3), and three equivalent O(4) atoms. There are two inequivalent Sc sites. In the first Sc site, Sc(1) is bonded in a 7-coordinate geometry to one O(1), one O(5), one O(6), two equivalent O(2), and two equivalent O(3) atoms. In the second Sc site, Sc(2) is bonded to one O(5), one O(6), three equivalent O(1), and three equivalent O(4) atoms to form distorted ScO8 hexagonal bipyramids that share edges with six equivalent Si(1)O6 octahedra. There are two inequivalent Si sites. In the first Si site, Si(1) is bonded to one O(2), one O(3), two equivalent O(1), and two equivalent O(4) atoms to form SiO6 octahedra that share corners with two equivalent Si(2)O6 octahedra, corners with four equivalent Si(1)O6 octahedra, and edges with two equivalent Sc(2)O8 hexagonal bipyramids. The corner-sharing octahedral tilt angles range from 40-49°. In the second Si site, Si(2) is bonded to three equivalent O(2) and three equivalent O(3) atoms to form corner-sharing SiO6 octahedra. The corner-sharing octahedral tilt angles range from 42-49°. There are six inequivalent O sites. In the first O site, O(4) is bonded in a 4-coordinate geometry to one Mg(1), one Sc(2), and two equivalent Si(1) atoms. In the second O site, O(5) is bonded to one Mg(1), one Sc(2), and three equivalent Sc(1) atoms to form a mixture of distorted edge and corner-sharing OMgSc4 trigonal bipyramids. In the third O site, O(6) is bonded in a rectangular see-saw-like geometry to one Sc(2) and three equivalent Sc(1) atoms. In the fourth O site, O(1) is bonded to one Sc(1), one Sc(2), and two equivalent Si(1) atoms to form distorted OSc2Si2 trigonal pyramids that share corners with four equivalent O(1)Sc2Si2 trigonal pyramids, edges with two equivalent O(2)Sc2Si2 tetrahedra, and  an edgeedge with one O(5)MgSc4 trigonal bipyramid. In the fifth O site, O(2) is bonded to two equivalent Sc(1), one Si(1), and one Si(2) atom to form distorted OSc2Si2 tetrahedra that share corners with four equivalent O(2)Sc2Si2 tetrahedra, corners with two equivalent O(5)MgSc4 trigonal bipyramids, and edges with two equivalent O(1)Sc2Si2 trigonal pyramids. In the sixth O site, O(3) is bonded in a 5-coordinate geometry to one Mg(1), two equivalent Sc(1), one Si(1), and one Si(2) atom. is represented by the Crystallographic Information File (CIF) [CIF]
data_MgSc4(Si2O7)2
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   6.908
_cell_length_b   6.908
_cell_length_c   6.908
_cell_angle_alpha   57.370
_cell_angle_beta   57.370
_cell_angle_gamma   57.370
_symmetry_Int_Tables_number   1
_cell_volume   218.972
_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  0.238  0.238  0.238  1.0
  Sc  Sc1  1  0.961  0.526  0.961  1.0
  Sc  Sc2  1  0.526  0.961  0.961  1.0
  Sc  Sc3  1  0.961  0.961  0.526  1.0
  Sc  Sc4  1  0.003  0.003  0.003  1.0
  Si  Si5  1  0.506  0.998  0.506  1.0
  Si  Si6  1  0.998  0.506  0.506  1.0
  Si  Si7  1  0.506  0.506  0.998  1.0
  Si  Si8  1  0.505  0.505  0.505  1.0
  O  O9  1  0.423  0.820  0.820  1.0
  O  O10  1  0.175  0.576  0.576  1.0
  O  O11  1  0.820  0.423  0.820  1.0
  O  O12  1  0.820  0.820  0.423  1.0
  O  O13  1  0.425  0.425  0.834  1.0
  O  O14  1  0.425  0.834  0.425  1.0
  O  O15  1  0.188  0.575  0.188  1.0
  O  O16  1  0.576  0.175  0.576  1.0
  O  O17  1  0.124  0.124  0.124  1.0
  O  O18  1  0.887  0.887  0.887  1.0
  O  O19  1  0.834  0.425  0.425  1.0
  O  O20  1  0.576  0.576  0.175  1.0
  O  O21  1  0.188  0.188  0.575  1.0
  O  O22  1  0.575  0.188  0.188  1.0
[/CIF]
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