The material described by CaSc4(Si2O7)2 crystallizes in the orthorhombic Imm2 space group. Ca(1) is bonded in a 8-coordinate geometry to two equivalent Si(1), one O(3), one O(4), and four equivalent O(1) atoms. There are two inequivalent Sc sites. In the first Sc site, Sc(1) is bonded in a 7-coordinate geometry to one O(5), one O(6), one O(7), two equivalent O(1), and two equivalent O(2) atoms. In the second Sc site, Sc(2) is bonded in a 6-coordinate geometry to one O(3), one O(5), one O(6), one O(8), and two equivalent O(1) atoms. There are two inequivalent Si sites. In the first Si site, Si(1) is bonded in a distorted trigonal non-coplanar geometry to one Ca(1), one O(8), two equivalent O(1), and two equivalent O(2) atoms. 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 corner-sharing SiO6 octahedra. The corner-sharing octahedral tilt angles range from 11-44°. There are eight inequivalent O sites. In the first O site, O(1) is bonded in a 5-coordinate geometry to one Ca(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 distorted bent 120 degrees geometry to one Sc(1), one Si(1), and one Si(2) atom. In the third O site, O(3) is bonded in a trigonal planar geometry to one Ca(1) and two equivalent Sc(2) atoms. In the fourth O site, O(4) is bonded in a distorted T-shaped geometry to one Ca(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 distorted OSc4 trigonal pyramids that share corners with two equivalent O(8)Sc2Si2 tetrahedra and corners with four equivalent O(6)Sc4 tetrahedra. In the sixth O site, O(6) is bonded to two equivalent Sc(1) and two equivalent Sc(2) atoms to form OSc4 tetrahedra that share corners with four equivalent O(5)Sc4 trigonal pyramids and  an edgeedge with one O(8)Sc2Si2 tetrahedra. In the seventh O site, O(7) is bonded in a 2-coordinate geometry to two equivalent Sc(1) and two equivalent Si(2) atoms. In the eighth O site, O(8) is bonded to two equivalent Sc(2) and two equivalent Si(1) atoms to form a mixture of edge and corner-sharing OSc2Si2 tetrahedra. is represented by the CIF card [CIF]
data_CaSc4(Si2O7)2
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   7.115
_cell_length_b   7.115
_cell_length_c   6.658
_cell_angle_alpha   62.103
_cell_angle_beta   62.103
_cell_angle_gamma   62.852
_symmetry_Int_Tables_number   1
_cell_volume   250.822
_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
  Ca  Ca0  1  0.699  0.699  0.551  1.0
  Sc  Sc1  1  0.949  0.490  0.030  1.0
  Sc  Sc2  1  0.490  0.949  0.030  1.0
  Sc  Sc3  1  0.016  0.016  0.476  1.0
  Sc  Sc4  1  0.016  0.016  0.991  1.0
  Si  Si5  1  0.452  0.081  0.483  1.0
  Si  Si6  1  0.081  0.452  0.483  1.0
  Si  Si7  1  0.482  0.482  0.024  1.0
  Si  Si8  1  0.482  0.482  0.513  1.0
  O  O9  1  0.398  0.813  0.883  1.0
  O  O10  1  0.190  0.525  0.601  1.0
  O  O11  1  0.813  0.398  0.883  1.0
  O  O12  1  0.907  0.907  0.343  1.0
  O  O13  1  0.466  0.466  0.784  1.0
  O  O14  1  0.398  0.813  0.405  1.0
  O  O15  1  0.190  0.525  0.184  1.0
  O  O16  1  0.525  0.190  0.601  1.0
  O  O17  1  0.158  0.158  0.092  1.0
  O  O18  1  0.866  0.866  0.884  1.0
  O  O19  1  0.813  0.398  0.405  1.0
  O  O20  1  0.546  0.546  0.204  1.0
  O  O21  1  0.167  0.167  0.583  1.0
  O  O22  1  0.525  0.190  0.184  1.0
[/CIF]
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The material described by CaSc4(Si2O7)2 crystallizes in the orthorhombic Imm2 space group. Ca(1) is bonded in a 8-coordinate geometry to two equivalent Si(1), one O(3), one O(4), and four equivalent O(1) atoms. There are two inequivalent Sc sites. In the first Sc site, Sc(1) is bonded in a 7-coordinate geometry to one O(5), one O(6), one O(7), two equivalent O(1), and two equivalent O(2) atoms. In the second Sc site, Sc(2) is bonded in a 6-coordinate geometry to one O(3), one O(5), one O(6), one O(8), and two equivalent O(1) atoms. There are two inequivalent Si sites. In the first Si site, Si(1) is bonded in a distorted trigonal non-coplanar geometry to one Ca(1), one O(8), two equivalent O(1), and two equivalent O(2) atoms. 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 corner-sharing SiO6 octahedra. The corner-sharing octahedral tilt angles range from 11-44°. There are eight inequivalent O sites. In the first O site, O(1) is bonded in a 5-coordinate geometry to one Ca(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 distorted bent 120 degrees geometry to one Sc(1), one Si(1), and one Si(2) atom. In the third O site, O(3) is bonded in a trigonal planar geometry to one Ca(1) and two equivalent Sc(2) atoms. In the fourth O site, O(4) is bonded in a distorted T-shaped geometry to one Ca(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 distorted OSc4 trigonal pyramids that share corners with two equivalent O(8)Sc2Si2 tetrahedra and corners with four equivalent O(6)Sc4 tetrahedra. In the sixth O site, O(6) is bonded to two equivalent Sc(1) and two equivalent Sc(2) atoms to form OSc4 tetrahedra that share corners with four equivalent O(5)Sc4 trigonal pyramids and  an edgeedge with one O(8)Sc2Si2 tetrahedra. In the seventh O site, O(7) is bonded in a 2-coordinate geometry to two equivalent Sc(1) and two equivalent Si(2) atoms. In the eighth O site, O(8) is bonded to two equivalent Sc(2) and two equivalent Si(1) atoms to form a mixture of edge and corner-sharing OSc2Si2 tetrahedra. is represented by the CIF card [CIF]
data_CaSc4(Si2O7)2
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   7.115
_cell_length_b   7.115
_cell_length_c   6.658
_cell_angle_alpha   62.103
_cell_angle_beta   62.103
_cell_angle_gamma   62.852
_symmetry_Int_Tables_number   1
_cell_volume   250.822
_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
  Ca  Ca0  1  0.699  0.699  0.551  1.0
  Sc  Sc1  1  0.949  0.490  0.030  1.0
  Sc  Sc2  1  0.490  0.949  0.030  1.0
  Sc  Sc3  1  0.016  0.016  0.476  1.0
  Sc  Sc4  1  0.016  0.016  0.991  1.0
  Si  Si5  1  0.452  0.081  0.483  1.0
  Si  Si6  1  0.081  0.452  0.483  1.0
  Si  Si7  1  0.482  0.482  0.024  1.0
  Si  Si8  1  0.482  0.482  0.513  1.0
  O  O9  1  0.398  0.813  0.883  1.0
  O  O10  1  0.190  0.525  0.601  1.0
  O  O11  1  0.813  0.398  0.883  1.0
  O  O12  1  0.907  0.907  0.343  1.0
  O  O13  1  0.466  0.466  0.784  1.0
  O  O14  1  0.398  0.813  0.405  1.0
  O  O15  1  0.190  0.525  0.184  1.0
  O  O16  1  0.525  0.190  0.601  1.0
  O  O17  1  0.158  0.158  0.092  1.0
  O  O18  1  0.866  0.866  0.884  1.0
  O  O19  1  0.813  0.398  0.405  1.0
  O  O20  1  0.546  0.546  0.204  1.0
  O  O21  1  0.167  0.167  0.583  1.0
  O  O22  1  0.525  0.190  0.184  1.0
[/CIF]
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