The compound described by Na2ZrSi4O11 crystallizes in the monoclinic C2/c space group. There are two inequivalent Na sites. In the first Na site, Na(1) is bonded in a 5-coordinate geometry to one O(5), two equivalent O(2), and two equivalent O(3) atoms. In the second Na site, Na(2) is bonded in a 4-coordinate geometry to two equivalent O(1) and two equivalent O(3) atoms. Zr(1) is bonded to two equivalent O(1), two equivalent O(2), and two equivalent O(3) atoms to form ZrO6 octahedra that share corners with two equivalent Si(2)O4 tetrahedra and corners with four equivalent Si(1)O4 tetrahedra. There are two inequivalent Si sites. In the first Si site, Si(1) is bonded to one O(1), one O(2), one O(4), and one O(6) atom to form SiO4 tetrahedra that share corners with two equivalent Zr(1)O6 octahedra and corners with two equivalent Si(2)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 18-41°. 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 Zr(1)O6 octahedra,  a cornercorner with one Si(2)O4 tetrahedra, and corners with two equivalent Si(1)O4 tetrahedra. The corner-sharing octahedral tilt angles are 40°. There are six inequivalent O sites. In the first O site, O(2) is bonded in a 3-coordinate geometry to one Na(1), one Zr(1), and one Si(1) atom. In the second O site, O(3) is bonded in a 4-coordinate geometry to one Na(1), one Na(2), one Zr(1), and one Si(2) atom. In the third O site, O(4) is bonded in a bent 150 degrees geometry to one Si(1) and one Si(2) atom. In the fourth O site, O(5) is bonded in a distorted trigonal planar geometry to one Na(1) and two equivalent Si(2) atoms. In the fifth O site, O(6) is bonded in a bent 150 degrees geometry to one Si(1) and one Si(2) atom. In the sixth O site, O(1) is bonded in a distorted trigonal non-coplanar geometry to one Na(2), one Zr(1), and one Si(1) atom. is represented by the CIF card [CIF]
data_Na2ZrSi4O11
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   7.587
_cell_length_b   7.587
_cell_length_c   8.694
_cell_angle_alpha   82.290
_cell_angle_beta   82.290
_cell_angle_gamma   84.958
_symmetry_Int_Tables_number   1
_cell_volume   490.173
_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
  Na  Na0  1  0.924  0.076  0.250  1.0
  Na  Na1  1  0.076  0.924  0.750  1.0
  Na  Na2  1  0.606  0.394  0.250  1.0
  Na  Na3  1  0.394  0.606  0.750  1.0
  Zr  Zr4  1  0.500  0.000  0.500  1.0
  Zr  Zr5  1  0.000  0.500  0.000  1.0
  Si  Si6  1  0.808  0.664  0.639  1.0
  Si  Si7  1  0.192  0.336  0.361  1.0
  Si  Si8  1  0.664  0.808  0.139  1.0
  Si  Si9  1  0.267  0.833  0.073  1.0
  Si  Si10  1  0.167  0.733  0.427  1.0
  Si  Si11  1  0.733  0.167  0.927  1.0
  Si  Si12  1  0.833  0.267  0.573  1.0
  Si  Si13  1  0.336  0.192  0.861  1.0
  O  O14  1  0.372  0.206  0.355  1.0
  O  O15  1  0.794  0.628  0.145  1.0
  O  O16  1  0.628  0.794  0.645  1.0
  O  O17  1  0.206  0.372  0.855  1.0
  O  O18  1  0.373  0.104  0.699  1.0
  O  O19  1  0.896  0.627  0.801  1.0
  O  O20  1  0.627  0.896  0.301  1.0
  O  O21  1  0.104  0.373  0.199  1.0
  O  O22  1  0.287  0.824  0.531  1.0
  O  O23  1  0.176  0.713  0.969  1.0
  O  O24  1  0.713  0.176  0.469  1.0
  O  O25  1  0.824  0.287  0.031  1.0
  O  O26  1  0.474  0.756  0.086  1.0
  O  O27  1  0.244  0.526  0.414  1.0
  O  O28  1  0.841  0.159  0.750  1.0
  O  O29  1  0.159  0.841  0.250  1.0
  O  O30  1  0.041  0.246  0.496  1.0
  O  O31  1  0.754  0.959  0.004  1.0
  O  O32  1  0.959  0.754  0.504  1.0
  O  O33  1  0.246  0.041  0.996  1.0
  O  O34  1  0.756  0.474  0.586  1.0
  O  O35  1  0.526  0.244  0.914  1.0
[/CIF]
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The compound described by Na2ZrSi4O11 crystallizes in the monoclinic C2/c space group. There are two inequivalent Na sites. In the first Na site, Na(1) is bonded in a 5-coordinate geometry to one O(5), two equivalent O(2), and two equivalent O(3) atoms. In the second Na site, Na(2) is bonded in a 4-coordinate geometry to two equivalent O(1) and two equivalent O(3) atoms. Zr(1) is bonded to two equivalent O(1), two equivalent O(2), and two equivalent O(3) atoms to form ZrO6 octahedra that share corners with two equivalent Si(2)O4 tetrahedra and corners with four equivalent Si(1)O4 tetrahedra. There are two inequivalent Si sites. In the first Si site, Si(1) is bonded to one O(1), one O(2), one O(4), and one O(6) atom to form SiO4 tetrahedra that share corners with two equivalent Zr(1)O6 octahedra and corners with two equivalent Si(2)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 18-41°. 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 Zr(1)O6 octahedra,  a cornercorner with one Si(2)O4 tetrahedra, and corners with two equivalent Si(1)O4 tetrahedra. The corner-sharing octahedral tilt angles are 40°. There are six inequivalent O sites. In the first O site, O(2) is bonded in a 3-coordinate geometry to one Na(1), one Zr(1), and one Si(1) atom. In the second O site, O(3) is bonded in a 4-coordinate geometry to one Na(1), one Na(2), one Zr(1), and one Si(2) atom. In the third O site, O(4) is bonded in a bent 150 degrees geometry to one Si(1) and one Si(2) atom. In the fourth O site, O(5) is bonded in a distorted trigonal planar geometry to one Na(1) and two equivalent Si(2) atoms. In the fifth O site, O(6) is bonded in a bent 150 degrees geometry to one Si(1) and one Si(2) atom. In the sixth O site, O(1) is bonded in a distorted trigonal non-coplanar geometry to one Na(2), one Zr(1), and one Si(1) atom. is represented by the CIF card [CIF]
data_Na2ZrSi4O11
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   7.587
_cell_length_b   7.587
_cell_length_c   8.694
_cell_angle_alpha   82.290
_cell_angle_beta   82.290
_cell_angle_gamma   84.958
_symmetry_Int_Tables_number   1
_cell_volume   490.173
_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
  Na  Na0  1  0.924  0.076  0.250  1.0
  Na  Na1  1  0.076  0.924  0.750  1.0
  Na  Na2  1  0.606  0.394  0.250  1.0
  Na  Na3  1  0.394  0.606  0.750  1.0
  Zr  Zr4  1  0.500  0.000  0.500  1.0
  Zr  Zr5  1  0.000  0.500  0.000  1.0
  Si  Si6  1  0.808  0.664  0.639  1.0
  Si  Si7  1  0.192  0.336  0.361  1.0
  Si  Si8  1  0.664  0.808  0.139  1.0
  Si  Si9  1  0.267  0.833  0.073  1.0
  Si  Si10  1  0.167  0.733  0.427  1.0
  Si  Si11  1  0.733  0.167  0.927  1.0
  Si  Si12  1  0.833  0.267  0.573  1.0
  Si  Si13  1  0.336  0.192  0.861  1.0
  O  O14  1  0.372  0.206  0.355  1.0
  O  O15  1  0.794  0.628  0.145  1.0
  O  O16  1  0.628  0.794  0.645  1.0
  O  O17  1  0.206  0.372  0.855  1.0
  O  O18  1  0.373  0.104  0.699  1.0
  O  O19  1  0.896  0.627  0.801  1.0
  O  O20  1  0.627  0.896  0.301  1.0
  O  O21  1  0.104  0.373  0.199  1.0
  O  O22  1  0.287  0.824  0.531  1.0
  O  O23  1  0.176  0.713  0.969  1.0
  O  O24  1  0.713  0.176  0.469  1.0
  O  O25  1  0.824  0.287  0.031  1.0
  O  O26  1  0.474  0.756  0.086  1.0
  O  O27  1  0.244  0.526  0.414  1.0
  O  O28  1  0.841  0.159  0.750  1.0
  O  O29  1  0.159  0.841  0.250  1.0
  O  O30  1  0.041  0.246  0.496  1.0
  O  O31  1  0.754  0.959  0.004  1.0
  O  O32  1  0.959  0.754  0.504  1.0
  O  O33  1  0.246  0.041  0.996  1.0
  O  O34  1  0.756  0.474  0.586  1.0
  O  O35  1  0.526  0.244  0.914  1.0
[/CIF]
.