The material structure described by Na4Hf2(SiO4)3 crystallizes in the trigonal R-3c space group. There are two inequivalent Na sites. In the first Na site, Na(1) is bonded in a 8-coordinate geometry to four equivalent O(1) and four equivalent O(2) atoms. In the second Na site, Na(2) is bonded in a distorted hexagonal planar geometry to six equivalent O(2) atoms. Hf(1) is bonded to three equivalent O(1) and three equivalent O(2) atoms to form HfO6 octahedra that share corners with six equivalent Si(1)O4 tetrahedra. Si(1) is bonded to two equivalent O(1) and two equivalent O(2) atoms to form SiO4 tetrahedra that share corners with four equivalent Hf(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 29-34°. There are two inequivalent O sites. In the first O site, O(2) is bonded to one Na(2), two equivalent Na(1), one Hf(1), and one Si(1) atom to form a mixture of distorted edge, corner, and face-sharing ONa3HfSi trigonal bipyramids. In the second O site, O(1) is bonded in a distorted bent 150 degrees geometry to two equivalent Na(1), one Hf(1), and one Si(1) atom. is represented by the CIF file [CIF]
data_Na4Hf2(SiO4)3
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   9.202
_cell_length_b   9.202
_cell_length_c   9.333
_cell_angle_alpha   60.464
_cell_angle_beta   60.464
_cell_angle_gamma   60.000
_symmetry_Int_Tables_number   1
_cell_volume   562.741
_cell_formula_units_Z   2
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
  Hf  Hf0  1  0.351  0.351  0.946  1.0
  Hf  Hf1  1  0.851  0.851  0.446  1.0
  Hf  Hf2  1  0.649  0.649  0.054  1.0
  Hf  Hf3  1  0.149  0.149  0.554  1.0
  Na  Na4  1  0.250  0.616  0.250  1.0
  Na  Na5  1  0.884  0.250  0.250  1.0
  Na  Na6  1  0.616  0.884  0.250  1.0
  Na  Na7  1  0.116  0.750  0.750  1.0
  Na  Na8  1  0.384  0.116  0.750  1.0
  Na  Na9  1  0.750  0.384  0.750  1.0
  Na  Na10  1  0.500  0.500  0.500  1.0
  Na  Na11  1  0.000  0.000  0.000  1.0
  O  O12  1  0.272  0.135  0.080  1.0
  O  O13  1  0.513  0.272  0.080  1.0
  O  O14  1  0.135  0.513  0.080  1.0
  O  O15  1  0.635  0.772  0.580  1.0
  O  O16  1  0.013  0.635  0.580  1.0
  O  O17  1  0.772  0.013  0.580  1.0
  O  O18  1  0.728  0.865  0.920  1.0
  O  O19  1  0.487  0.728  0.920  1.0
  O  O20  1  0.865  0.487  0.920  1.0
  O  O21  1  0.365  0.228  0.420  1.0
  O  O22  1  0.987  0.365  0.420  1.0
  O  O23  1  0.228  0.987  0.420  1.0
  O  O24  1  0.575  0.221  0.771  1.0
  O  O25  1  0.433  0.575  0.771  1.0
  O  O26  1  0.221  0.433  0.771  1.0
  O  O27  1  0.721  0.075  0.271  1.0
  O  O28  1  0.933  0.721  0.271  1.0
  O  O29  1  0.075  0.933  0.271  1.0
  O  O30  1  0.425  0.779  0.229  1.0
  O  O31  1  0.567  0.425  0.229  1.0
  O  O32  1  0.779  0.567  0.229  1.0
  O  O33  1  0.279  0.925  0.729  1.0
  O  O34  1  0.067  0.279  0.729  1.0
  O  O35  1  0.925  0.067  0.729  1.0
  Si  Si36  1  0.250  0.958  0.250  1.0
  Si  Si37  1  0.542  0.250  0.250  1.0
  Si  Si38  1  0.958  0.542  0.250  1.0
  Si  Si39  1  0.458  0.750  0.750  1.0
  Si  Si40  1  0.042  0.458  0.750  1.0
  Si  Si41  1  0.750  0.042  0.750  1.0
[/CIF]
.
The material structure described by Na4Hf2(SiO4)3 crystallizes in the trigonal R-3c space group. There are two inequivalent Na sites. In the first Na site, Na(1) is bonded in a 8-coordinate geometry to four equivalent O(1) and four equivalent O(2) atoms. In the second Na site, Na(2) is bonded in a distorted hexagonal planar geometry to six equivalent O(2) atoms. Hf(1) is bonded to three equivalent O(1) and three equivalent O(2) atoms to form HfO6 octahedra that share corners with six equivalent Si(1)O4 tetrahedra. Si(1) is bonded to two equivalent O(1) and two equivalent O(2) atoms to form SiO4 tetrahedra that share corners with four equivalent Hf(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 29-34°. There are two inequivalent O sites. In the first O site, O(2) is bonded to one Na(2), two equivalent Na(1), one Hf(1), and one Si(1) atom to form a mixture of distorted edge, corner, and face-sharing ONa3HfSi trigonal bipyramids. In the second O site, O(1) is bonded in a distorted bent 150 degrees geometry to two equivalent Na(1), one Hf(1), and one Si(1) atom. is represented by the CIF file [CIF]
data_Na4Hf2(SiO4)3
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   9.202
_cell_length_b   9.202
_cell_length_c   9.333
_cell_angle_alpha   60.464
_cell_angle_beta   60.464
_cell_angle_gamma   60.000
_symmetry_Int_Tables_number   1
_cell_volume   562.741
_cell_formula_units_Z   2
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
  Hf  Hf0  1  0.351  0.351  0.946  1.0
  Hf  Hf1  1  0.851  0.851  0.446  1.0
  Hf  Hf2  1  0.649  0.649  0.054  1.0
  Hf  Hf3  1  0.149  0.149  0.554  1.0
  Na  Na4  1  0.250  0.616  0.250  1.0
  Na  Na5  1  0.884  0.250  0.250  1.0
  Na  Na6  1  0.616  0.884  0.250  1.0
  Na  Na7  1  0.116  0.750  0.750  1.0
  Na  Na8  1  0.384  0.116  0.750  1.0
  Na  Na9  1  0.750  0.384  0.750  1.0
  Na  Na10  1  0.500  0.500  0.500  1.0
  Na  Na11  1  0.000  0.000  0.000  1.0
  O  O12  1  0.272  0.135  0.080  1.0
  O  O13  1  0.513  0.272  0.080  1.0
  O  O14  1  0.135  0.513  0.080  1.0
  O  O15  1  0.635  0.772  0.580  1.0
  O  O16  1  0.013  0.635  0.580  1.0
  O  O17  1  0.772  0.013  0.580  1.0
  O  O18  1  0.728  0.865  0.920  1.0
  O  O19  1  0.487  0.728  0.920  1.0
  O  O20  1  0.865  0.487  0.920  1.0
  O  O21  1  0.365  0.228  0.420  1.0
  O  O22  1  0.987  0.365  0.420  1.0
  O  O23  1  0.228  0.987  0.420  1.0
  O  O24  1  0.575  0.221  0.771  1.0
  O  O25  1  0.433  0.575  0.771  1.0
  O  O26  1  0.221  0.433  0.771  1.0
  O  O27  1  0.721  0.075  0.271  1.0
  O  O28  1  0.933  0.721  0.271  1.0
  O  O29  1  0.075  0.933  0.271  1.0
  O  O30  1  0.425  0.779  0.229  1.0
  O  O31  1  0.567  0.425  0.229  1.0
  O  O32  1  0.779  0.567  0.229  1.0
  O  O33  1  0.279  0.925  0.729  1.0
  O  O34  1  0.067  0.279  0.729  1.0
  O  O35  1  0.925  0.067  0.729  1.0
  Si  Si36  1  0.250  0.958  0.250  1.0
  Si  Si37  1  0.542  0.250  0.250  1.0
  Si  Si38  1  0.958  0.542  0.250  1.0
  Si  Si39  1  0.458  0.750  0.750  1.0
  Si  Si40  1  0.042  0.458  0.750  1.0
  Si  Si41  1  0.750  0.042  0.750  1.0
[/CIF]
.