The material described by Tb2SiO5 crystallizes in the monoclinic P2_1/c space group. There are two inequivalent Tb sites. In the first Tb site, Tb(1) is bonded in a 8-coordinate geometry to one O(3), two equivalent O(1), two equivalent O(2), and three equivalent O(5) atoms. In the second Tb site, Tb(2) is bonded to one O(1), three equivalent O(3), and three equivalent O(4) atoms to form distorted TbO7 hexagonal pyramids that share corners with two equivalent Si(1)O4 tetrahedra, edges with six equivalent Tb(2)O7 hexagonal pyramids, and  an edgeedge with one Si(1)O4 tetrahedra. Si(1) is bonded to one O(1), one O(2), one O(4), and one O(5) atom to form SiO4 tetrahedra that share corners with two equivalent Tb(2)O7 hexagonal pyramids and  an edgeedge with one Tb(2)O7 hexagonal pyramid. There are five inequivalent O sites. In the first O site, O(1) is bonded in a 4-coordinate geometry to one Tb(2), two equivalent Tb(1), and one Si(1) atom. In the second O site, O(2) is bonded in a 1-coordinate geometry to two equivalent Tb(1) and one Si(1) atom. In the third O site, O(3) is bonded to one Tb(1) and three equivalent Tb(2) atoms to form a mixture of corner and edge-sharing OTb4 tetrahedra. In the fourth O site, O(4) is bonded in a 4-coordinate geometry to three equivalent Tb(2) and one Si(1) atom. In the fifth O site, O(5) is bonded in a 4-coordinate geometry to three equivalent Tb(1) and one Si(1) atom. is represented by the CIF card [CIF]
data_Tb2SiO5
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   6.911
_cell_length_b   6.704
_cell_length_c   9.071
_cell_angle_alpha   73.392
_cell_angle_beta   90.000
_cell_angle_gamma   90.000
_symmetry_Int_Tables_number   1
_cell_volume   402.751
_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
  Tb  Tb0  1  0.359  0.429  0.380  1.0
  Tb  Tb1  1  0.641  0.571  0.620  1.0
  Tb  Tb2  1  0.859  0.071  0.620  1.0
  Tb  Tb3  1  0.141  0.929  0.380  1.0
  Tb  Tb4  1  0.375  0.267  0.028  1.0
  Tb  Tb5  1  0.625  0.733  0.972  1.0
  Tb  Tb6  1  0.875  0.233  0.972  1.0
  Tb  Tb7  1  0.125  0.767  0.028  1.0
  Si  Si8  1  0.912  0.468  0.298  1.0
  Si  Si9  1  0.088  0.532  0.702  1.0
  Si  Si10  1  0.412  0.032  0.702  1.0
  Si  Si11  1  0.588  0.968  0.298  1.0
  O  O12  1  0.429  0.153  0.293  1.0
  O  O13  1  0.571  0.847  0.707  1.0
  O  O14  1  0.929  0.347  0.707  1.0
  O  O15  1  0.071  0.653  0.293  1.0
  O  O16  1  0.222  0.032  0.601  1.0
  O  O17  1  0.778  0.968  0.399  1.0
  O  O18  1  0.722  0.468  0.399  1.0
  O  O19  1  0.278  0.532  0.601  1.0
  O  O20  1  0.119  0.056  0.116  1.0
  O  O21  1  0.881  0.944  0.884  1.0
  O  O22  1  0.619  0.444  0.884  1.0
  O  O23  1  0.381  0.556  0.116  1.0
  O  O24  1  0.136  0.492  0.886  1.0
  O  O25  1  0.864  0.508  0.114  1.0
  O  O26  1  0.636  0.008  0.114  1.0
  O  O27  1  0.364  0.992  0.886  1.0
  O  O28  1  0.047  0.265  0.371  1.0
  O  O29  1  0.953  0.735  0.629  1.0
  O  O30  1  0.547  0.235  0.629  1.0
  O  O31  1  0.453  0.765  0.371  1.0
[/CIF]
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The material described by Tb2SiO5 crystallizes in the monoclinic P2_1/c space group. There are two inequivalent Tb sites. In the first Tb site, Tb(1) is bonded in a 8-coordinate geometry to one O(3), two equivalent O(1), two equivalent O(2), and three equivalent O(5) atoms. In the second Tb site, Tb(2) is bonded to one O(1), three equivalent O(3), and three equivalent O(4) atoms to form distorted TbO7 hexagonal pyramids that share corners with two equivalent Si(1)O4 tetrahedra, edges with six equivalent Tb(2)O7 hexagonal pyramids, and  an edgeedge with one Si(1)O4 tetrahedra. Si(1) is bonded to one O(1), one O(2), one O(4), and one O(5) atom to form SiO4 tetrahedra that share corners with two equivalent Tb(2)O7 hexagonal pyramids and  an edgeedge with one Tb(2)O7 hexagonal pyramid. There are five inequivalent O sites. In the first O site, O(1) is bonded in a 4-coordinate geometry to one Tb(2), two equivalent Tb(1), and one Si(1) atom. In the second O site, O(2) is bonded in a 1-coordinate geometry to two equivalent Tb(1) and one Si(1) atom. In the third O site, O(3) is bonded to one Tb(1) and three equivalent Tb(2) atoms to form a mixture of corner and edge-sharing OTb4 tetrahedra. In the fourth O site, O(4) is bonded in a 4-coordinate geometry to three equivalent Tb(2) and one Si(1) atom. In the fifth O site, O(5) is bonded in a 4-coordinate geometry to three equivalent Tb(1) and one Si(1) atom. is represented by the CIF card [CIF]
data_Tb2SiO5
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   6.911
_cell_length_b   6.704
_cell_length_c   9.071
_cell_angle_alpha   73.392
_cell_angle_beta   90.000
_cell_angle_gamma   90.000
_symmetry_Int_Tables_number   1
_cell_volume   402.751
_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
  Tb  Tb0  1  0.359  0.429  0.380  1.0
  Tb  Tb1  1  0.641  0.571  0.620  1.0
  Tb  Tb2  1  0.859  0.071  0.620  1.0
  Tb  Tb3  1  0.141  0.929  0.380  1.0
  Tb  Tb4  1  0.375  0.267  0.028  1.0
  Tb  Tb5  1  0.625  0.733  0.972  1.0
  Tb  Tb6  1  0.875  0.233  0.972  1.0
  Tb  Tb7  1  0.125  0.767  0.028  1.0
  Si  Si8  1  0.912  0.468  0.298  1.0
  Si  Si9  1  0.088  0.532  0.702  1.0
  Si  Si10  1  0.412  0.032  0.702  1.0
  Si  Si11  1  0.588  0.968  0.298  1.0
  O  O12  1  0.429  0.153  0.293  1.0
  O  O13  1  0.571  0.847  0.707  1.0
  O  O14  1  0.929  0.347  0.707  1.0
  O  O15  1  0.071  0.653  0.293  1.0
  O  O16  1  0.222  0.032  0.601  1.0
  O  O17  1  0.778  0.968  0.399  1.0
  O  O18  1  0.722  0.468  0.399  1.0
  O  O19  1  0.278  0.532  0.601  1.0
  O  O20  1  0.119  0.056  0.116  1.0
  O  O21  1  0.881  0.944  0.884  1.0
  O  O22  1  0.619  0.444  0.884  1.0
  O  O23  1  0.381  0.556  0.116  1.0
  O  O24  1  0.136  0.492  0.886  1.0
  O  O25  1  0.864  0.508  0.114  1.0
  O  O26  1  0.636  0.008  0.114  1.0
  O  O27  1  0.364  0.992  0.886  1.0
  O  O28  1  0.047  0.265  0.371  1.0
  O  O29  1  0.953  0.735  0.629  1.0
  O  O30  1  0.547  0.235  0.629  1.0
  O  O31  1  0.453  0.765  0.371  1.0
[/CIF]
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