The compound described by Lu2Si2O7 crystallizes in the tetragonal P4_32_12 space group. Lu(1) is bonded to two equivalent O(2), two equivalent O(3), and three equivalent O(1) atoms to form distorted LuO7 pentagonal bipyramids that share corners with five equivalent Si(1)O4 tetrahedra, edges with five equivalent Lu(1)O7 pentagonal bipyramids, and  an edgeedge with one Si(1)O4 tetrahedra. Si(1) is bonded to one O(1), one O(2), one O(3), and one O(4) atom to form SiO4 tetrahedra that share corners with five equivalent Lu(1)O7 pentagonal bipyramids,  a cornercorner with one Si(1)O4 tetrahedra, and  an edgeedge with one Lu(1)O7 pentagonal bipyramid. There are four inequivalent O sites. In the first O site, O(3) is bonded in a distorted trigonal planar geometry to two equivalent Lu(1) and one Si(1) atom. In the second O site, O(4) is bonded in a bent 150 degrees geometry to two equivalent Si(1) atoms. In the third O site, O(1) is bonded to three equivalent Lu(1) and one Si(1) atom to form a mixture of distorted edge and corner-sharing OLu3Si trigonal pyramids. In the fourth O site, O(2) is bonded in a 3-coordinate geometry to two equivalent Lu(1) and one Si(1) atom. is represented by the CIF card [CIF]
data_Lu2Si2O7
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   6.593
_cell_length_b   6.593
_cell_length_c   12.024
_cell_angle_alpha   90.000
_cell_angle_beta   90.000
_cell_angle_gamma   90.000
_symmetry_Int_Tables_number   1
_cell_volume   522.700
_cell_formula_units_Z   4
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
  Lu  Lu0  1  0.148  0.377  0.116  1.0
  Lu  Lu1  1  0.852  0.623  0.616  1.0
  Lu  Lu2  1  0.877  0.352  0.366  1.0
  Lu  Lu3  1  0.123  0.648  0.866  1.0
  Lu  Lu4  1  0.623  0.852  0.384  1.0
  Lu  Lu5  1  0.377  0.148  0.884  1.0
  Lu  Lu6  1  0.352  0.877  0.634  1.0
  Lu  Lu7  1  0.648  0.123  0.134  1.0
  Si  Si8  1  0.154  0.903  0.122  1.0
  Si  Si9  1  0.846  0.097  0.622  1.0
  Si  Si10  1  0.403  0.346  0.372  1.0
  Si  Si11  1  0.597  0.654  0.872  1.0
  Si  Si12  1  0.097  0.846  0.378  1.0
  Si  Si13  1  0.903  0.154  0.878  1.0
  Si  Si14  1  0.346  0.403  0.628  1.0
  Si  Si15  1  0.654  0.597  0.128  1.0
  O  O16  1  0.337  0.054  0.073  1.0
  O  O17  1  0.663  0.946  0.573  1.0
  O  O18  1  0.554  0.163  0.323  1.0
  O  O19  1  0.446  0.837  0.823  1.0
  O  O20  1  0.946  0.663  0.427  1.0
  O  O21  1  0.054  0.337  0.927  1.0
  O  O22  1  0.163  0.554  0.677  1.0
  O  O23  1  0.837  0.446  0.177  1.0
  O  O24  1  0.972  0.071  0.126  1.0
  O  O25  1  0.028  0.929  0.626  1.0
  O  O26  1  0.571  0.528  0.376  1.0
  O  O27  1  0.429  0.472  0.876  1.0
  O  O28  1  0.929  0.028  0.374  1.0
  O  O29  1  0.071  0.972  0.874  1.0
  O  O30  1  0.528  0.571  0.624  1.0
  O  O31  1  0.472  0.429  0.124  1.0
  O  O32  1  0.138  0.694  0.048  1.0
  O  O33  1  0.862  0.306  0.548  1.0
  O  O34  1  0.194  0.362  0.298  1.0
  O  O35  1  0.806  0.638  0.798  1.0
  O  O36  1  0.306  0.862  0.452  1.0
  O  O37  1  0.694  0.138  0.952  1.0
  O  O38  1  0.362  0.194  0.702  1.0
  O  O39  1  0.638  0.806  0.202  1.0
  O  O40  1  0.185  0.815  0.250  1.0
  O  O41  1  0.815  0.185  0.750  1.0
  O  O42  1  0.315  0.315  0.500  1.0
  O  O43  1  0.685  0.685  0.000  1.0
[/CIF]
.
The compound described by Lu2Si2O7 crystallizes in the tetragonal P4_32_12 space group. Lu(1) is bonded to two equivalent O(2), two equivalent O(3), and three equivalent O(1) atoms to form distorted LuO7 pentagonal bipyramids that share corners with five equivalent Si(1)O4 tetrahedra, edges with five equivalent Lu(1)O7 pentagonal bipyramids, and  an edgeedge with one Si(1)O4 tetrahedra. Si(1) is bonded to one O(1), one O(2), one O(3), and one O(4) atom to form SiO4 tetrahedra that share corners with five equivalent Lu(1)O7 pentagonal bipyramids,  a cornercorner with one Si(1)O4 tetrahedra, and  an edgeedge with one Lu(1)O7 pentagonal bipyramid. There are four inequivalent O sites. In the first O site, O(3) is bonded in a distorted trigonal planar geometry to two equivalent Lu(1) and one Si(1) atom. In the second O site, O(4) is bonded in a bent 150 degrees geometry to two equivalent Si(1) atoms. In the third O site, O(1) is bonded to three equivalent Lu(1) and one Si(1) atom to form a mixture of distorted edge and corner-sharing OLu3Si trigonal pyramids. In the fourth O site, O(2) is bonded in a 3-coordinate geometry to two equivalent Lu(1) and one Si(1) atom. is represented by the CIF card [CIF]
data_Lu2Si2O7
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   6.593
_cell_length_b   6.593
_cell_length_c   12.024
_cell_angle_alpha   90.000
_cell_angle_beta   90.000
_cell_angle_gamma   90.000
_symmetry_Int_Tables_number   1
_cell_volume   522.700
_cell_formula_units_Z   4
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
  Lu  Lu0  1  0.148  0.377  0.116  1.0
  Lu  Lu1  1  0.852  0.623  0.616  1.0
  Lu  Lu2  1  0.877  0.352  0.366  1.0
  Lu  Lu3  1  0.123  0.648  0.866  1.0
  Lu  Lu4  1  0.623  0.852  0.384  1.0
  Lu  Lu5  1  0.377  0.148  0.884  1.0
  Lu  Lu6  1  0.352  0.877  0.634  1.0
  Lu  Lu7  1  0.648  0.123  0.134  1.0
  Si  Si8  1  0.154  0.903  0.122  1.0
  Si  Si9  1  0.846  0.097  0.622  1.0
  Si  Si10  1  0.403  0.346  0.372  1.0
  Si  Si11  1  0.597  0.654  0.872  1.0
  Si  Si12  1  0.097  0.846  0.378  1.0
  Si  Si13  1  0.903  0.154  0.878  1.0
  Si  Si14  1  0.346  0.403  0.628  1.0
  Si  Si15  1  0.654  0.597  0.128  1.0
  O  O16  1  0.337  0.054  0.073  1.0
  O  O17  1  0.663  0.946  0.573  1.0
  O  O18  1  0.554  0.163  0.323  1.0
  O  O19  1  0.446  0.837  0.823  1.0
  O  O20  1  0.946  0.663  0.427  1.0
  O  O21  1  0.054  0.337  0.927  1.0
  O  O22  1  0.163  0.554  0.677  1.0
  O  O23  1  0.837  0.446  0.177  1.0
  O  O24  1  0.972  0.071  0.126  1.0
  O  O25  1  0.028  0.929  0.626  1.0
  O  O26  1  0.571  0.528  0.376  1.0
  O  O27  1  0.429  0.472  0.876  1.0
  O  O28  1  0.929  0.028  0.374  1.0
  O  O29  1  0.071  0.972  0.874  1.0
  O  O30  1  0.528  0.571  0.624  1.0
  O  O31  1  0.472  0.429  0.124  1.0
  O  O32  1  0.138  0.694  0.048  1.0
  O  O33  1  0.862  0.306  0.548  1.0
  O  O34  1  0.194  0.362  0.298  1.0
  O  O35  1  0.806  0.638  0.798  1.0
  O  O36  1  0.306  0.862  0.452  1.0
  O  O37  1  0.694  0.138  0.952  1.0
  O  O38  1  0.362  0.194  0.702  1.0
  O  O39  1  0.638  0.806  0.202  1.0
  O  O40  1  0.185  0.815  0.250  1.0
  O  O41  1  0.815  0.185  0.750  1.0
  O  O42  1  0.315  0.315  0.500  1.0
  O  O43  1  0.685  0.685  0.000  1.0
[/CIF]
.