The structure described by Na6CaZr(SiO3)6 crystallizes in the trigonal R3c space group. There are two inequivalent Na sites. In the first Na site, Na(1) is bonded in a 2-coordinate geometry to two equivalent O(5) atoms. In the second Na site, Na(2) is bonded in a 7-coordinate geometry to one O(1), one O(2), one O(3), one O(4), one O(5), and two equivalent O(6) atoms. Ca(1) is bonded to three equivalent O(2) and three equivalent O(3) atoms to form distorted CaO6 octahedra that share corners with six equivalent Si(1)O4 tetrahedra and  a faceface with one Zr(1)O6 octahedra. Zr(1) is bonded to three equivalent O(2) and three equivalent O(6) atoms to form ZrO6 octahedra that share corners with three equivalent Si(1)O4 tetrahedra, corners with three equivalent Si(2)O4 tetrahedra, and  a faceface with one Ca(1)O6 octahedra. There are two 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(4) atom to form SiO4 tetrahedra that share  a cornercorner with one Zr(1)O6 octahedra, corners with two equivalent Ca(1)O6 octahedra, and corners with two equivalent Si(2)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 38-50°. In the second Si site, Si(2) is bonded to one O(1), one O(4), one O(5), and one O(6) atom to form SiO4 tetrahedra that share  a cornercorner with one Zr(1)O6 octahedra and corners with two equivalent Si(1)O4 tetrahedra. The corner-sharing octahedral tilt angles are 35°. There are six inequivalent O sites. In the first O site, O(5) is bonded to one Na(2), two equivalent Na(1), and one Si(2) atom to form distorted corner-sharing ONa3Si trigonal pyramids. In the second O site, O(6) is bonded in a 4-coordinate geometry to two equivalent Na(2), one Zr(1), and one Si(2) atom. In the third O site, O(1) is bonded in a 2-coordinate geometry to one Na(2), one Si(1), and one Si(2) atom. In the fourth O site, O(2) is bonded in a 2-coordinate geometry to one Na(2), one Ca(1), one Zr(1), and one Si(1) atom. In the fifth O site, O(3) is bonded in a 3-coordinate geometry to one Na(2), one Ca(1), and one Si(1) atom. In the sixth O site, O(4) is bonded in a 2-coordinate geometry to one Na(2), one Si(1), and one Si(2) atom. is represented by the CIF file [CIF]
data_Na6CaZr(SiO3)6
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   7.494
_cell_length_b   7.494
_cell_length_c   7.494
_cell_angle_alpha   88.551
_cell_angle_beta   88.551
_cell_angle_gamma   88.551
_symmetry_Int_Tables_number   1
_cell_volume   420.416
_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
  Ca  Ca0  1  0.246  0.246  0.246  1.0
  Na  Na1  1  0.550  0.550  0.954  1.0
  Na  Na2  1  0.954  0.550  0.550  1.0
  Na  Na3  1  0.550  0.954  0.550  1.0
  Na  Na4  1  0.988  0.988  0.527  1.0
  Na  Na5  1  0.527  0.988  0.988  1.0
  Na  Na6  1  0.988  0.527  0.988  1.0
  O  O7  1  0.497  0.241  0.752  1.0
  O  O8  1  0.916  0.188  0.188  1.0
  O  O9  1  0.188  0.188  0.916  1.0
  O  O10  1  0.752  0.497  0.241  1.0
  O  O11  1  0.241  0.752  0.497  1.0
  O  O12  1  0.548  0.209  0.209  1.0
  O  O13  1  0.209  0.209  0.548  1.0
  O  O14  1  0.209  0.548  0.209  1.0
  O  O15  1  0.188  0.916  0.188  1.0
  O  O16  1  0.449  0.786  0.786  1.0
  O  O17  1  0.786  0.786  0.449  1.0
  O  O18  1  0.241  0.497  0.752  1.0
  O  O19  1  0.087  0.807  0.807  1.0
  O  O20  1  0.807  0.807  0.087  1.0
  O  O21  1  0.497  0.752  0.241  1.0
  O  O22  1  0.807  0.087  0.807  1.0
  O  O23  1  0.786  0.449  0.786  1.0
  O  O24  1  0.752  0.241  0.497  1.0
  Si  Si25  1  0.734  0.278  0.278  1.0
  Si  Si26  1  0.278  0.278  0.734  1.0
  Si  Si27  1  0.278  0.734  0.278  1.0
  Si  Si28  1  0.267  0.716  0.716  1.0
  Si  Si29  1  0.716  0.716  0.267  1.0
  Si  Si30  1  0.716  0.267  0.716  1.0
  Zr  Zr31  1  0.991  0.991  0.991  1.0
[/CIF]
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The structure described by Na6CaZr(SiO3)6 crystallizes in the trigonal R3c space group. There are two inequivalent Na sites. In the first Na site, Na(1) is bonded in a 2-coordinate geometry to two equivalent O(5) atoms. In the second Na site, Na(2) is bonded in a 7-coordinate geometry to one O(1), one O(2), one O(3), one O(4), one O(5), and two equivalent O(6) atoms. Ca(1) is bonded to three equivalent O(2) and three equivalent O(3) atoms to form distorted CaO6 octahedra that share corners with six equivalent Si(1)O4 tetrahedra and  a faceface with one Zr(1)O6 octahedra. Zr(1) is bonded to three equivalent O(2) and three equivalent O(6) atoms to form ZrO6 octahedra that share corners with three equivalent Si(1)O4 tetrahedra, corners with three equivalent Si(2)O4 tetrahedra, and  a faceface with one Ca(1)O6 octahedra. There are two 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(4) atom to form SiO4 tetrahedra that share  a cornercorner with one Zr(1)O6 octahedra, corners with two equivalent Ca(1)O6 octahedra, and corners with two equivalent Si(2)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 38-50°. In the second Si site, Si(2) is bonded to one O(1), one O(4), one O(5), and one O(6) atom to form SiO4 tetrahedra that share  a cornercorner with one Zr(1)O6 octahedra and corners with two equivalent Si(1)O4 tetrahedra. The corner-sharing octahedral tilt angles are 35°. There are six inequivalent O sites. In the first O site, O(5) is bonded to one Na(2), two equivalent Na(1), and one Si(2) atom to form distorted corner-sharing ONa3Si trigonal pyramids. In the second O site, O(6) is bonded in a 4-coordinate geometry to two equivalent Na(2), one Zr(1), and one Si(2) atom. In the third O site, O(1) is bonded in a 2-coordinate geometry to one Na(2), one Si(1), and one Si(2) atom. In the fourth O site, O(2) is bonded in a 2-coordinate geometry to one Na(2), one Ca(1), one Zr(1), and one Si(1) atom. In the fifth O site, O(3) is bonded in a 3-coordinate geometry to one Na(2), one Ca(1), and one Si(1) atom. In the sixth O site, O(4) is bonded in a 2-coordinate geometry to one Na(2), one Si(1), and one Si(2) atom. is represented by the CIF file [CIF]
data_Na6CaZr(SiO3)6
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   7.494
_cell_length_b   7.494
_cell_length_c   7.494
_cell_angle_alpha   88.551
_cell_angle_beta   88.551
_cell_angle_gamma   88.551
_symmetry_Int_Tables_number   1
_cell_volume   420.416
_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
  Ca  Ca0  1  0.246  0.246  0.246  1.0
  Na  Na1  1  0.550  0.550  0.954  1.0
  Na  Na2  1  0.954  0.550  0.550  1.0
  Na  Na3  1  0.550  0.954  0.550  1.0
  Na  Na4  1  0.988  0.988  0.527  1.0
  Na  Na5  1  0.527  0.988  0.988  1.0
  Na  Na6  1  0.988  0.527  0.988  1.0
  O  O7  1  0.497  0.241  0.752  1.0
  O  O8  1  0.916  0.188  0.188  1.0
  O  O9  1  0.188  0.188  0.916  1.0
  O  O10  1  0.752  0.497  0.241  1.0
  O  O11  1  0.241  0.752  0.497  1.0
  O  O12  1  0.548  0.209  0.209  1.0
  O  O13  1  0.209  0.209  0.548  1.0
  O  O14  1  0.209  0.548  0.209  1.0
  O  O15  1  0.188  0.916  0.188  1.0
  O  O16  1  0.449  0.786  0.786  1.0
  O  O17  1  0.786  0.786  0.449  1.0
  O  O18  1  0.241  0.497  0.752  1.0
  O  O19  1  0.087  0.807  0.807  1.0
  O  O20  1  0.807  0.807  0.087  1.0
  O  O21  1  0.497  0.752  0.241  1.0
  O  O22  1  0.807  0.087  0.807  1.0
  O  O23  1  0.786  0.449  0.786  1.0
  O  O24  1  0.752  0.241  0.497  1.0
  Si  Si25  1  0.734  0.278  0.278  1.0
  Si  Si26  1  0.278  0.278  0.734  1.0
  Si  Si27  1  0.278  0.734  0.278  1.0
  Si  Si28  1  0.267  0.716  0.716  1.0
  Si  Si29  1  0.716  0.716  0.267  1.0
  Si  Si30  1  0.716  0.267  0.716  1.0
  Zr  Zr31  1  0.991  0.991  0.991  1.0
[/CIF]
.