The compound described by Sc2Si2O7 crystallizes in the monoclinic C2/m space group. Sc(1) is bonded to two equivalent O(3) and four equivalent O(1) atoms to form distorted ScO6 pentagonal pyramids that share corners with six equivalent Si(1)O4 tetrahedra and edges with three equivalent Sc(1)O6 pentagonal pyramids. Si(1) is bonded to one O(2), one O(3), and two equivalent O(1) atoms to form SiO4 tetrahedra that share corners with six equivalent Sc(1)O6 pentagonal pyramids and  a cornercorner with one Si(1)O4 tetrahedra. There are three inequivalent O sites. In the first O site, O(1) is bonded in a distorted trigonal planar geometry to two equivalent Sc(1) and one Si(1) atom. In the second O site, O(2) is bonded in a linear geometry to two equivalent Si(1) atoms. In the third O site, O(3) is bonded in a distorted trigonal planar geometry to two equivalent Sc(1) and one Si(1) atom. is represented by the Crystallographic Information File (CIF) [CIF]
data_Sc2Si2O7
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   4.691
_cell_length_b   5.363
_cell_length_c   5.363
_cell_angle_alpha   105.116
_cell_angle_beta   97.700
_cell_angle_gamma   97.700
_symmetry_Int_Tables_number   1
_cell_volume   127.040
_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
  Sc  Sc0  1  0.000  0.310  0.690  1.0
  Sc  Sc1  1  0.000  0.690  0.310  1.0
  Si  Si2  1  0.408  0.224  0.224  1.0
  Si  Si3  1  0.592  0.776  0.776  1.0
  O  O4  1  0.787  0.922  0.607  1.0
  O  O5  1  0.213  0.393  0.078  1.0
  O  O6  1  0.213  0.078  0.393  1.0
  O  O7  1  0.787  0.607  0.922  1.0
  O  O8  1  0.500  0.000  0.000  1.0
  O  O9  1  0.280  0.606  0.606  1.0
  O  O10  1  0.720  0.394  0.394  1.0
[/CIF]
.
The compound described by Sc2Si2O7 crystallizes in the monoclinic C2/m space group. Sc(1) is bonded to two equivalent O(3) and four equivalent O(1) atoms to form distorted ScO6 pentagonal pyramids that share corners with six equivalent Si(1)O4 tetrahedra and edges with three equivalent Sc(1)O6 pentagonal pyramids. Si(1) is bonded to one O(2), one O(3), and two equivalent O(1) atoms to form SiO4 tetrahedra that share corners with six equivalent Sc(1)O6 pentagonal pyramids and  a cornercorner with one Si(1)O4 tetrahedra. There are three inequivalent O sites. In the first O site, O(1) is bonded in a distorted trigonal planar geometry to two equivalent Sc(1) and one Si(1) atom. In the second O site, O(2) is bonded in a linear geometry to two equivalent Si(1) atoms. In the third O site, O(3) is bonded in a distorted trigonal planar geometry to two equivalent Sc(1) and one Si(1) atom. is represented by the Crystallographic Information File (CIF) [CIF]
data_Sc2Si2O7
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   4.691
_cell_length_b   5.363
_cell_length_c   5.363
_cell_angle_alpha   105.116
_cell_angle_beta   97.700
_cell_angle_gamma   97.700
_symmetry_Int_Tables_number   1
_cell_volume   127.040
_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
  Sc  Sc0  1  0.000  0.310  0.690  1.0
  Sc  Sc1  1  0.000  0.690  0.310  1.0
  Si  Si2  1  0.408  0.224  0.224  1.0
  Si  Si3  1  0.592  0.776  0.776  1.0
  O  O4  1  0.787  0.922  0.607  1.0
  O  O5  1  0.213  0.393  0.078  1.0
  O  O6  1  0.213  0.078  0.393  1.0
  O  O7  1  0.787  0.607  0.922  1.0
  O  O8  1  0.500  0.000  0.000  1.0
  O  O9  1  0.280  0.606  0.606  1.0
  O  O10  1  0.720  0.394  0.394  1.0
[/CIF]
.