The structure described by NaTb(SiO3)2 crystallizes in the triclinic P-1 space group. There are two inequivalent Na sites. In the first Na site, Na(1) is bonded in a hexagonal planar geometry to two equivalent O(3), two equivalent O(6), and two equivalent O(9) atoms. In the second Na site, Na(2) is bonded in a 5-coordinate geometry to one O(1), one O(7), one O(9), and two equivalent O(2) atoms. There are two inequivalent Tb sites. In the first Tb site, Tb(1) is bonded to two equivalent O(4), two equivalent O(7), and two equivalent O(8) atoms to form TbO6 octahedra that share corners with two equivalent Si(2)O4 tetrahedra, corners with four equivalent Si(3)O4 tetrahedra, and edges with two equivalent Tb(2)O6 octahedra. In the second Tb site, Tb(2) is bonded to one O(1), one O(2), one O(4), one O(8), and two equivalent O(5) atoms to form TbO6 octahedra that share  a cornercorner with one Si(3)O4 tetrahedra, corners with two equivalent Si(1)O4 tetrahedra, corners with three equivalent Si(2)O4 tetrahedra,  an edgeedge with one Tb(1)O6 octahedra, and  an edgeedge with one Tb(2)O6 octahedra. There are three inequivalent Si sites. In the first Si site, Si(1) is bonded to one O(1), one O(2), one O(3), and one O(9) atom to form SiO4 tetrahedra that share corners with two equivalent Tb(2)O6 octahedra,  a cornercorner with one Si(2)O4 tetrahedra, and  a cornercorner with one Si(3)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 41-48°. In the second Si site, Si(2) is bonded to one O(3), one O(4), one O(5), and one O(6) atom to form SiO4 tetrahedra that share  a cornercorner with one Tb(1)O6 octahedra, corners with three equivalent Tb(2)O6 octahedra,  a cornercorner with one Si(1)O4 tetrahedra, and  a cornercorner with one Si(3)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 45-61°. In the third Si site, Si(3) is bonded to one O(6), one O(7), one O(8), and one O(9) atom to form SiO4 tetrahedra that share  a cornercorner with one Tb(2)O6 octahedra, corners with two equivalent Tb(1)O6 octahedra,  a cornercorner with one Si(1)O4 tetrahedra, and  a cornercorner with one Si(2)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 46-62°. There are nine inequivalent O sites. In the first O site, O(1) is bonded in a distorted trigonal planar geometry to one Na(2), one Tb(2), and one Si(1) atom. In the second O site, O(2) is bonded to two equivalent Na(2), one Tb(2), and one Si(1) atom to form distorted edge-sharing ONa2TbSi trigonal pyramids. In the third O site, O(3) is bonded in a 3-coordinate geometry to one Na(1), one Si(1), and one Si(2) atom. In the fourth O site, O(4) is bonded in a distorted trigonal planar geometry to one Tb(1), one Tb(2), and one Si(2) atom. In the fifth O site, O(5) is bonded in a distorted trigonal planar geometry to two equivalent Tb(2) and one Si(2) atom. In the sixth O site, O(6) is bonded in a distorted bent 150 degrees geometry to one Na(1), one Si(2), and one Si(3) atom. In the seventh O site, O(7) is bonded in a distorted trigonal planar geometry to one Na(2), one Tb(1), and one Si(3) atom. In the eighth O site, O(8) is bonded in a distorted trigonal planar geometry to one Tb(1), one Tb(2), and one Si(3) atom. In the ninth O site, O(9) is bonded in a distorted rectangular see-saw-like geometry to one Na(1), one Na(2), one Si(1), and one Si(3) atom. is represented by the CIF card [CIF]
data_NaTb(SiO3)2
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   5.480
_cell_length_b   9.347
_cell_length_c   9.683
_cell_angle_alpha   117.310
_cell_angle_beta   97.042
_cell_angle_gamma   100.091
_symmetry_Int_Tables_number   1
_cell_volume   422.000
_cell_formula_units_Z   3
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
  Na  Na0  1  0.000  0.000  0.000  1.0
  Na  Na1  1  0.165  0.604  0.937  1.0
  Na  Na2  1  0.835  0.396  0.063  1.0
  Tb  Tb3  1  0.000  0.500  0.500  1.0
  Tb  Tb4  1  0.320  0.777  0.365  1.0
  Tb  Tb5  1  0.680  0.223  0.635  1.0
  Si  Si6  1  0.772  0.759  0.124  1.0
  Si  Si7  1  0.228  0.241  0.876  1.0
  Si  Si8  1  0.894  0.882  0.634  1.0
  Si  Si9  1  0.106  0.118  0.366  1.0
  Si  Si10  1  0.604  0.639  0.749  1.0
  Si  Si11  1  0.396  0.361  0.251  1.0
  O  O12  1  0.500  0.715  0.158  1.0
  O  O13  1  0.500  0.285  0.842  1.0
  O  O14  1  0.981  0.676  0.165  1.0
  O  O15  1  0.019  0.324  0.835  1.0
  O  O16  1  0.894  0.963  0.212  1.0
  O  O17  1  0.106  0.037  0.788  1.0
  O  O18  1  0.033  0.756  0.515  1.0
  O  O19  1  0.967  0.244  0.485  1.0
  O  O20  1  0.701  0.950  0.553  1.0
  O  O21  1  0.299  0.050  0.447  1.0
  O  O22  1  0.739  0.789  0.717  1.0
  O  O23  1  0.261  0.211  0.283  1.0
  O  O24  1  0.305  0.614  0.728  1.0
  O  O25  1  0.695  0.386  0.272  1.0
  O  O26  1  0.694  0.474  0.639  1.0
  O  O27  1  0.306  0.526  0.361  1.0
  O  O28  1  0.755  0.711  0.935  1.0
  O  O29  1  0.245  0.289  0.065  1.0
[/CIF]
.
The structure described by NaTb(SiO3)2 crystallizes in the triclinic P-1 space group. There are two inequivalent Na sites. In the first Na site, Na(1) is bonded in a hexagonal planar geometry to two equivalent O(3), two equivalent O(6), and two equivalent O(9) atoms. In the second Na site, Na(2) is bonded in a 5-coordinate geometry to one O(1), one O(7), one O(9), and two equivalent O(2) atoms. There are two inequivalent Tb sites. In the first Tb site, Tb(1) is bonded to two equivalent O(4), two equivalent O(7), and two equivalent O(8) atoms to form TbO6 octahedra that share corners with two equivalent Si(2)O4 tetrahedra, corners with four equivalent Si(3)O4 tetrahedra, and edges with two equivalent Tb(2)O6 octahedra. In the second Tb site, Tb(2) is bonded to one O(1), one O(2), one O(4), one O(8), and two equivalent O(5) atoms to form TbO6 octahedra that share  a cornercorner with one Si(3)O4 tetrahedra, corners with two equivalent Si(1)O4 tetrahedra, corners with three equivalent Si(2)O4 tetrahedra,  an edgeedge with one Tb(1)O6 octahedra, and  an edgeedge with one Tb(2)O6 octahedra. There are three inequivalent Si sites. In the first Si site, Si(1) is bonded to one O(1), one O(2), one O(3), and one O(9) atom to form SiO4 tetrahedra that share corners with two equivalent Tb(2)O6 octahedra,  a cornercorner with one Si(2)O4 tetrahedra, and  a cornercorner with one Si(3)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 41-48°. In the second Si site, Si(2) is bonded to one O(3), one O(4), one O(5), and one O(6) atom to form SiO4 tetrahedra that share  a cornercorner with one Tb(1)O6 octahedra, corners with three equivalent Tb(2)O6 octahedra,  a cornercorner with one Si(1)O4 tetrahedra, and  a cornercorner with one Si(3)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 45-61°. In the third Si site, Si(3) is bonded to one O(6), one O(7), one O(8), and one O(9) atom to form SiO4 tetrahedra that share  a cornercorner with one Tb(2)O6 octahedra, corners with two equivalent Tb(1)O6 octahedra,  a cornercorner with one Si(1)O4 tetrahedra, and  a cornercorner with one Si(2)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 46-62°. There are nine inequivalent O sites. In the first O site, O(1) is bonded in a distorted trigonal planar geometry to one Na(2), one Tb(2), and one Si(1) atom. In the second O site, O(2) is bonded to two equivalent Na(2), one Tb(2), and one Si(1) atom to form distorted edge-sharing ONa2TbSi trigonal pyramids. In the third O site, O(3) is bonded in a 3-coordinate geometry to one Na(1), one Si(1), and one Si(2) atom. In the fourth O site, O(4) is bonded in a distorted trigonal planar geometry to one Tb(1), one Tb(2), and one Si(2) atom. In the fifth O site, O(5) is bonded in a distorted trigonal planar geometry to two equivalent Tb(2) and one Si(2) atom. In the sixth O site, O(6) is bonded in a distorted bent 150 degrees geometry to one Na(1), one Si(2), and one Si(3) atom. In the seventh O site, O(7) is bonded in a distorted trigonal planar geometry to one Na(2), one Tb(1), and one Si(3) atom. In the eighth O site, O(8) is bonded in a distorted trigonal planar geometry to one Tb(1), one Tb(2), and one Si(3) atom. In the ninth O site, O(9) is bonded in a distorted rectangular see-saw-like geometry to one Na(1), one Na(2), one Si(1), and one Si(3) atom. is represented by the CIF card [CIF]
data_NaTb(SiO3)2
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   5.480
_cell_length_b   9.347
_cell_length_c   9.683
_cell_angle_alpha   117.310
_cell_angle_beta   97.042
_cell_angle_gamma   100.091
_symmetry_Int_Tables_number   1
_cell_volume   422.000
_cell_formula_units_Z   3
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
  Na  Na0  1  0.000  0.000  0.000  1.0
  Na  Na1  1  0.165  0.604  0.937  1.0
  Na  Na2  1  0.835  0.396  0.063  1.0
  Tb  Tb3  1  0.000  0.500  0.500  1.0
  Tb  Tb4  1  0.320  0.777  0.365  1.0
  Tb  Tb5  1  0.680  0.223  0.635  1.0
  Si  Si6  1  0.772  0.759  0.124  1.0
  Si  Si7  1  0.228  0.241  0.876  1.0
  Si  Si8  1  0.894  0.882  0.634  1.0
  Si  Si9  1  0.106  0.118  0.366  1.0
  Si  Si10  1  0.604  0.639  0.749  1.0
  Si  Si11  1  0.396  0.361  0.251  1.0
  O  O12  1  0.500  0.715  0.158  1.0
  O  O13  1  0.500  0.285  0.842  1.0
  O  O14  1  0.981  0.676  0.165  1.0
  O  O15  1  0.019  0.324  0.835  1.0
  O  O16  1  0.894  0.963  0.212  1.0
  O  O17  1  0.106  0.037  0.788  1.0
  O  O18  1  0.033  0.756  0.515  1.0
  O  O19  1  0.967  0.244  0.485  1.0
  O  O20  1  0.701  0.950  0.553  1.0
  O  O21  1  0.299  0.050  0.447  1.0
  O  O22  1  0.739  0.789  0.717  1.0
  O  O23  1  0.261  0.211  0.283  1.0
  O  O24  1  0.305  0.614  0.728  1.0
  O  O25  1  0.695  0.386  0.272  1.0
  O  O26  1  0.694  0.474  0.639  1.0
  O  O27  1  0.306  0.526  0.361  1.0
  O  O28  1  0.755  0.711  0.935  1.0
  O  O29  1  0.245  0.289  0.065  1.0
[/CIF]
.