The structure described by LiSc4(Si2O7)2 crystallizes in the orthorhombic Imm2 space group. Li(1) is bonded to one O(3), one O(4), and four equivalent O(1) atoms to form LiO6 octahedra that share corners with six equivalent Sc(1)O8 hexagonal bipyramids, corners with six equivalent Sc(2)O8 hexagonal bipyramids, faces with two equivalent Si(1)O6 octahedra, and faces with two equivalent Si(2)O6 octahedra. There are two inequivalent Sc sites. In the first Sc site, Sc(1) is bonded to one O(4), one O(5), one O(6), one O(7), two equivalent O(1), and two equivalent O(2) atoms to form distorted ScO8 hexagonal bipyramids that share corners with three equivalent Li(1)O6 octahedra, edges with two equivalent Sc(1)O8 hexagonal bipyramids, edges with four equivalent Sc(2)O8 hexagonal bipyramids, edges with two equivalent Si(1)O6 octahedra, and edges with four equivalent Si(2)O6 octahedra. The corner-sharing octahedral tilt angles are 45°. In the second Sc site, Sc(2) is bonded to one O(3), one O(5), one O(6), one O(8), two equivalent O(1), and two equivalent O(2) atoms to form distorted ScO8 hexagonal bipyramids that share corners with three equivalent Li(1)O6 octahedra, edges with two equivalent Sc(2)O8 hexagonal bipyramids, edges with four equivalent Sc(1)O8 hexagonal bipyramids, edges with two equivalent Si(2)O6 octahedra, and edges with four equivalent Si(1)O6 octahedra. The corner-sharing octahedral tilt angles are 45°. There are two inequivalent Si sites. In the first Si site, Si(1) is bonded to one O(3), one O(8), two equivalent O(1), and two equivalent O(2) atoms to form distorted SiO6 octahedra that share corners with two equivalent Si(1)O6 octahedra, corners with four equivalent Si(2)O6 octahedra, edges with two equivalent Sc(1)O8 hexagonal bipyramids, edges with four equivalent Sc(2)O8 hexagonal bipyramids, and  a faceface with one Li(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 39-50°. In the second Si site, Si(2) is bonded to one O(4), one O(7), two equivalent O(1), and two equivalent O(2) atoms to form distorted SiO6 octahedra that share corners with two equivalent Si(2)O6 octahedra, corners with four equivalent Si(1)O6 octahedra, edges with two equivalent Sc(2)O8 hexagonal bipyramids, edges with four equivalent Sc(1)O8 hexagonal bipyramids, and  a faceface with one Li(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 39-49°. There are eight inequivalent O sites. In the first O site, O(1) is bonded in a 5-coordinate geometry to one Li(1), one Sc(1), one Sc(2), one Si(1), and one Si(2) atom. In the second O site, O(2) is bonded in a 4-coordinate geometry to one Sc(1), one Sc(2), one Si(1), and one Si(2) atom. In the third O site, O(3) is bonded in a 5-coordinate geometry to one Li(1), two equivalent Sc(2), and two equivalent Si(1) atoms. In the fourth O site, O(4) is bonded in a 5-coordinate geometry to one Li(1), two equivalent Sc(1), and two equivalent Si(2) atoms. In the fifth O site, O(5) is bonded to two equivalent Sc(1) and two equivalent Sc(2) atoms to form corner-sharing OSc4 tetrahedra. In the sixth O site, O(6) is bonded to two equivalent Sc(1) and two equivalent Sc(2) atoms to form corner-sharing OSc4 tetrahedra. In the seventh O site, O(7) is bonded in a 4-coordinate geometry to two equivalent Sc(1) and two equivalent Si(2) atoms. In the eighth O site, O(8) is bonded in a 4-coordinate geometry to two equivalent Sc(2) and two equivalent Si(1) atoms. is represented by the Crystallographic Information File (CIF) [CIF]
data_LiSc4(Si2O7)2
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   6.715
_cell_length_b   6.715
_cell_length_c   6.713
_cell_angle_alpha   60.008
_cell_angle_beta   60.008
_cell_angle_gamma   60.107
_symmetry_Int_Tables_number   1
_cell_volume   214.226
_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
  Li  Li0  1  0.626  0.626  0.624  1.0
  Sc  Sc1  1  1.000  0.500  0.000  1.0
  Sc  Sc2  1  0.500  1.000  0.000  1.0
  Sc  Sc3  1  1.000  1.000  0.500  1.0
  Sc  Sc4  1  1.000  1.000  0.000  1.0
  Si  Si5  1  0.493  0.020  0.493  1.0
  Si  Si6  1  0.020  0.493  0.493  1.0
  Si  Si7  1  0.494  0.494  0.019  1.0
  Si  Si8  1  0.494  0.494  0.494  1.0
  O  O9  1  0.428  0.823  0.822  1.0
  O  O10  1  0.180  0.571  0.571  1.0
  O  O11  1  0.823  0.428  0.822  1.0
  O  O12  1  0.823  0.823  0.427  1.0
  O  O13  1  0.428  0.428  0.822  1.0
  O  O14  1  0.428  0.823  0.427  1.0
  O  O15  1  0.180  0.571  0.179  1.0
  O  O16  1  0.571  0.180  0.571  1.0
  O  O17  1  0.125  0.125  0.125  1.0
  O  O18  1  0.875  0.875  0.875  1.0
  O  O19  1  0.823  0.428  0.427  1.0
  O  O20  1  0.571  0.571  0.179  1.0
  O  O21  1  0.179  0.179  0.571  1.0
  O  O22  1  0.571  0.180  0.179  1.0
[/CIF]
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The structure described by LiSc4(Si2O7)2 crystallizes in the orthorhombic Imm2 space group. Li(1) is bonded to one O(3), one O(4), and four equivalent O(1) atoms to form LiO6 octahedra that share corners with six equivalent Sc(1)O8 hexagonal bipyramids, corners with six equivalent Sc(2)O8 hexagonal bipyramids, faces with two equivalent Si(1)O6 octahedra, and faces with two equivalent Si(2)O6 octahedra. There are two inequivalent Sc sites. In the first Sc site, Sc(1) is bonded to one O(4), one O(5), one O(6), one O(7), two equivalent O(1), and two equivalent O(2) atoms to form distorted ScO8 hexagonal bipyramids that share corners with three equivalent Li(1)O6 octahedra, edges with two equivalent Sc(1)O8 hexagonal bipyramids, edges with four equivalent Sc(2)O8 hexagonal bipyramids, edges with two equivalent Si(1)O6 octahedra, and edges with four equivalent Si(2)O6 octahedra. The corner-sharing octahedral tilt angles are 45°. In the second Sc site, Sc(2) is bonded to one O(3), one O(5), one O(6), one O(8), two equivalent O(1), and two equivalent O(2) atoms to form distorted ScO8 hexagonal bipyramids that share corners with three equivalent Li(1)O6 octahedra, edges with two equivalent Sc(2)O8 hexagonal bipyramids, edges with four equivalent Sc(1)O8 hexagonal bipyramids, edges with two equivalent Si(2)O6 octahedra, and edges with four equivalent Si(1)O6 octahedra. The corner-sharing octahedral tilt angles are 45°. There are two inequivalent Si sites. In the first Si site, Si(1) is bonded to one O(3), one O(8), two equivalent O(1), and two equivalent O(2) atoms to form distorted SiO6 octahedra that share corners with two equivalent Si(1)O6 octahedra, corners with four equivalent Si(2)O6 octahedra, edges with two equivalent Sc(1)O8 hexagonal bipyramids, edges with four equivalent Sc(2)O8 hexagonal bipyramids, and  a faceface with one Li(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 39-50°. In the second Si site, Si(2) is bonded to one O(4), one O(7), two equivalent O(1), and two equivalent O(2) atoms to form distorted SiO6 octahedra that share corners with two equivalent Si(2)O6 octahedra, corners with four equivalent Si(1)O6 octahedra, edges with two equivalent Sc(2)O8 hexagonal bipyramids, edges with four equivalent Sc(1)O8 hexagonal bipyramids, and  a faceface with one Li(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 39-49°. There are eight inequivalent O sites. In the first O site, O(1) is bonded in a 5-coordinate geometry to one Li(1), one Sc(1), one Sc(2), one Si(1), and one Si(2) atom. In the second O site, O(2) is bonded in a 4-coordinate geometry to one Sc(1), one Sc(2), one Si(1), and one Si(2) atom. In the third O site, O(3) is bonded in a 5-coordinate geometry to one Li(1), two equivalent Sc(2), and two equivalent Si(1) atoms. In the fourth O site, O(4) is bonded in a 5-coordinate geometry to one Li(1), two equivalent Sc(1), and two equivalent Si(2) atoms. In the fifth O site, O(5) is bonded to two equivalent Sc(1) and two equivalent Sc(2) atoms to form corner-sharing OSc4 tetrahedra. In the sixth O site, O(6) is bonded to two equivalent Sc(1) and two equivalent Sc(2) atoms to form corner-sharing OSc4 tetrahedra. In the seventh O site, O(7) is bonded in a 4-coordinate geometry to two equivalent Sc(1) and two equivalent Si(2) atoms. In the eighth O site, O(8) is bonded in a 4-coordinate geometry to two equivalent Sc(2) and two equivalent Si(1) atoms. is represented by the Crystallographic Information File (CIF) [CIF]
data_LiSc4(Si2O7)2
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   6.715
_cell_length_b   6.715
_cell_length_c   6.713
_cell_angle_alpha   60.008
_cell_angle_beta   60.008
_cell_angle_gamma   60.107
_symmetry_Int_Tables_number   1
_cell_volume   214.226
_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
  Li  Li0  1  0.626  0.626  0.624  1.0
  Sc  Sc1  1  1.000  0.500  0.000  1.0
  Sc  Sc2  1  0.500  1.000  0.000  1.0
  Sc  Sc3  1  1.000  1.000  0.500  1.0
  Sc  Sc4  1  1.000  1.000  0.000  1.0
  Si  Si5  1  0.493  0.020  0.493  1.0
  Si  Si6  1  0.020  0.493  0.493  1.0
  Si  Si7  1  0.494  0.494  0.019  1.0
  Si  Si8  1  0.494  0.494  0.494  1.0
  O  O9  1  0.428  0.823  0.822  1.0
  O  O10  1  0.180  0.571  0.571  1.0
  O  O11  1  0.823  0.428  0.822  1.0
  O  O12  1  0.823  0.823  0.427  1.0
  O  O13  1  0.428  0.428  0.822  1.0
  O  O14  1  0.428  0.823  0.427  1.0
  O  O15  1  0.180  0.571  0.179  1.0
  O  O16  1  0.571  0.180  0.571  1.0
  O  O17  1  0.125  0.125  0.125  1.0
  O  O18  1  0.875  0.875  0.875  1.0
  O  O19  1  0.823  0.428  0.427  1.0
  O  O20  1  0.571  0.571  0.179  1.0
  O  O21  1  0.179  0.179  0.571  1.0
  O  O22  1  0.571  0.180  0.179  1.0
[/CIF]
.