The structure described by CaZrSi6O17 crystallizes in the monoclinic C2 space group. Ca(1) is bonded to one O(17), one O(18), one O(5), one O(6), one O(7), one O(8), and one O(9) atom to form distorted CaO7 hexagonal pyramids that share  a cornercorner with one Si(3)O4 tetrahedra,  a cornercorner with one Si(4)O4 tetrahedra, edges with two equivalent Zr(1)O6 octahedra,  an edgeedge with one Si(1)O4 tetrahedra, and  an edgeedge with one Si(2)O4 tetrahedra. Zr(1) is bonded to one O(15), one O(16), one O(5), one O(6), one O(7), and one O(8) atom to form ZrO6 octahedra that share  a cornercorner with one Si(1)O4 tetrahedra,  a cornercorner with one Si(2)O4 tetrahedra,  a cornercorner with one Si(3)O4 tetrahedra,  a cornercorner with one Si(4)O4 tetrahedra,  a cornercorner with one Si(5)O4 tetrahedra,  a cornercorner with one Si(6)O4 tetrahedra, and edges with two equivalent Ca(1)O7 hexagonal pyramids. There are six inequivalent Si sites. In the first Si site, Si(1) is bonded to one O(11), one O(3), one O(5), and one O(9) atom to form SiO4 tetrahedra that share  a cornercorner with one Zr(1)O6 octahedra,  a cornercorner with one Si(2)O4 tetrahedra,  a cornercorner with one Si(4)O4 tetrahedra,  a cornercorner with one Si(5)O4 tetrahedra, and  an edgeedge with one Ca(1)O7 hexagonal pyramid. The corner-sharing octahedral tilt angles are 22°. In the second Si site, Si(2) is bonded to one O(13), one O(4), one O(7), and one O(9) atom to form SiO4 tetrahedra that share  a cornercorner with one Zr(1)O6 octahedra,  a cornercorner with one Si(1)O4 tetrahedra,  a cornercorner with one Si(3)O4 tetrahedra,  a cornercorner with one Si(6)O4 tetrahedra, and  an edgeedge with one Ca(1)O7 hexagonal pyramid. The corner-sharing octahedral tilt angles are 23°. In the third Si site, Si(3) is bonded to one O(10), one O(12), one O(4), and one O(6) atom to form SiO4 tetrahedra that share  a cornercorner with one Ca(1)O7 hexagonal pyramid,  a cornercorner with one Zr(1)O6 octahedra,  a cornercorner with one Si(2)O4 tetrahedra,  a cornercorner with one Si(4)O4 tetrahedra, and  a cornercorner with one Si(5)O4 tetrahedra. The corner-sharing octahedral tilt angles are 48°. In the fourth Si site, Si(4) is bonded to one O(10), one O(14), one O(3), and one O(8) atom to form SiO4 tetrahedra that share  a cornercorner with one Ca(1)O7 hexagonal pyramid,  a cornercorner with one Zr(1)O6 octahedra,  a cornercorner with one Si(1)O4 tetrahedra,  a cornercorner with one Si(3)O4 tetrahedra, and  a cornercorner with one Si(6)O4 tetrahedra. The corner-sharing octahedral tilt angles are 46°. In the fifth Si site, Si(5) is bonded to one O(1), one O(11), one O(12), and one O(16) atom to form SiO4 tetrahedra that share  a cornercorner with one Zr(1)O6 octahedra,  a cornercorner with one Si(1)O4 tetrahedra,  a cornercorner with one Si(3)O4 tetrahedra, and  a cornercorner with one Si(5)O4 tetrahedra. The corner-sharing octahedral tilt angles are 25°. In the sixth Si site, Si(6) is bonded to one O(13), one O(14), one O(15), and one O(2) atom to form SiO4 tetrahedra that share  a cornercorner with one Zr(1)O6 octahedra,  a cornercorner with one Si(2)O4 tetrahedra,  a cornercorner with one Si(4)O4 tetrahedra, and  a cornercorner with one Si(6)O4 tetrahedra. The corner-sharing octahedral tilt angles are 20°. There are eighteen inequivalent O sites. In the first O site, O(1) is bonded in a bent 150 degrees geometry to two equivalent Si(5) atoms. In the second O site, O(2) is bonded in a bent 150 degrees geometry to two equivalent Si(6) atoms. In the third O site, O(3) is bonded in a bent 150 degrees geometry to one Si(1) and one Si(4) atom. In the fourth O site, O(4) is bonded in a bent 150 degrees geometry to one Si(2) and one Si(3) atom. In the fifth O site, O(5) is bonded in a 3-coordinate geometry to one Ca(1), one Zr(1), and one Si(1) atom. In the sixth O site, O(6) is bonded in a distorted trigonal planar geometry to one Ca(1), one Zr(1), and one Si(3) atom. In the seventh O site, O(7) is bonded in a 3-coordinate geometry to one Ca(1), one Zr(1), and one Si(2) atom. In the eighth O site, O(8) is bonded in a 3-coordinate geometry to one Ca(1), one Zr(1), and one Si(4) atom. In the ninth O site, O(9) is bonded in a distorted T-shaped geometry to one Ca(1), one Si(1), and one Si(2) atom. In the tenth O site, O(10) is bonded in a bent 150 degrees geometry to one Si(3) and one Si(4) atom. In the eleventh O site, O(11) is bonded in a bent 150 degrees geometry to one Si(1) and one Si(5) atom. In the twelfth O site, O(12) is bonded in a bent 150 degrees geometry to one Si(3) and one Si(5) atom. In the thirteenth O site, O(13) is bonded in a bent 150 degrees geometry to one Si(2) and one Si(6) atom. In the fourteenth O site, O(14) is bonded in a bent 150 degrees geometry to one Si(4) and one Si(6) atom. In the fifteenth O site, O(15) is bonded in a bent 150 degrees geometry to one Zr(1) and one Si(6) atom. In the sixteenth O site, O(16) is bonded in a bent 150 degrees geometry to one Zr(1) and one Si(5) atom. In the seventeenth O site, O(17) is bonded in a single-bond geometry to one Ca(1) atom. In the eighteenth O site, O(18) is bonded in a single-bond geometry to one Ca(1) atom. is represented by the CIF card [CIF]
data_CaZrSi6O17
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   10.056
_cell_length_b   10.056
_cell_length_c   7.949
_cell_angle_alpha   76.320
_cell_angle_beta   76.320
_cell_angle_gamma   89.716
_symmetry_Int_Tables_number   1
_cell_volume   757.821
_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
  Ca  Ca0  1  0.989  0.496  0.958  1.0
  Ca  Ca1  1  0.504  0.011  0.042  1.0
  Zr  Zr2  1  0.249  0.254  0.995  1.0
  Zr  Zr3  1  0.746  0.751  0.005  1.0
  Si  Si4  1  0.052  0.329  0.656  1.0
  Si  Si5  1  0.671  0.948  0.344  1.0
  Si  Si6  1  0.820  0.557  0.660  1.0
  Si  Si7  1  0.443  0.180  0.340  1.0
  Si  Si8  1  0.978  0.709  0.270  1.0
  Si  Si9  1  0.291  0.022  0.730  1.0
  Si  Si10  1  0.202  0.492  0.270  1.0
  Si  Si11  1  0.508  0.798  0.730  1.0
  Si  Si12  1  0.989  0.023  0.695  1.0
  Si  Si13  1  0.977  0.011  0.305  1.0
  Si  Si14  1  0.511  0.495  0.699  1.0
  Si  Si15  1  0.505  0.489  0.301  1.0
  O  O16  1  0.010  0.990  0.500  1.0
  O  O17  1  0.487  0.513  0.500  1.0
  O  O18  1  0.152  0.375  0.456  1.0
  O  O19  1  0.625  0.848  0.544  1.0
  O  O20  1  0.862  0.655  0.459  1.0
  O  O21  1  0.345  0.138  0.541  1.0
  O  O22  1  0.131  0.329  0.812  1.0
  O  O23  1  0.671  0.869  0.188  1.0
  O  O24  1  0.919  0.678  0.107  1.0
  O  O25  1  0.322  0.081  0.893  1.0
  O  O26  1  0.824  0.639  0.813  1.0
  O  O27  1  0.361  0.176  0.187  1.0
  O  O28  1  0.172  0.429  0.108  1.0
  O  O29  1  0.571  0.828  0.892  1.0
  O  O30  1  0.937  0.444  0.690  1.0
  O  O31  1  0.556  0.063  0.310  1.0
  O  O32  1  0.116  0.627  0.286  1.0
  O  O33  1  0.373  0.884  0.714  1.0
  O  O34  1  0.970  0.186  0.680  1.0
  O  O35  1  0.814  0.030  0.320  1.0
  O  O36  1  0.016  0.871  0.237  1.0
  O  O37  1  0.129  0.984  0.763  1.0
  O  O38  1  0.675  0.474  0.693  1.0
  O  O39  1  0.526  0.325  0.307  1.0
  O  O40  1  0.364  0.530  0.238  1.0
  O  O41  1  0.470  0.636  0.762  1.0
  O  O42  1  0.418  0.368  0.839  1.0
  O  O43  1  0.632  0.582  0.161  1.0
  O  O44  1  0.858  0.934  0.839  1.0
  O  O45  1  0.066  0.142  0.161  1.0
  O  O46  1  0.920  0.307  0.221  1.0
  O  O47  1  0.693  0.080  0.779  1.0
  O  O48  1  0.189  0.643  0.898  1.0
  O  O49  1  0.357  0.811  0.102  1.0
[/CIF]
.
The structure described by CaZrSi6O17 crystallizes in the monoclinic C2 space group. Ca(1) is bonded to one O(17), one O(18), one O(5), one O(6), one O(7), one O(8), and one O(9) atom to form distorted CaO7 hexagonal pyramids that share  a cornercorner with one Si(3)O4 tetrahedra,  a cornercorner with one Si(4)O4 tetrahedra, edges with two equivalent Zr(1)O6 octahedra,  an edgeedge with one Si(1)O4 tetrahedra, and  an edgeedge with one Si(2)O4 tetrahedra. Zr(1) is bonded to one O(15), one O(16), one O(5), one O(6), one O(7), and one O(8) atom to form ZrO6 octahedra that share  a cornercorner with one Si(1)O4 tetrahedra,  a cornercorner with one Si(2)O4 tetrahedra,  a cornercorner with one Si(3)O4 tetrahedra,  a cornercorner with one Si(4)O4 tetrahedra,  a cornercorner with one Si(5)O4 tetrahedra,  a cornercorner with one Si(6)O4 tetrahedra, and edges with two equivalent Ca(1)O7 hexagonal pyramids. There are six inequivalent Si sites. In the first Si site, Si(1) is bonded to one O(11), one O(3), one O(5), and one O(9) atom to form SiO4 tetrahedra that share  a cornercorner with one Zr(1)O6 octahedra,  a cornercorner with one Si(2)O4 tetrahedra,  a cornercorner with one Si(4)O4 tetrahedra,  a cornercorner with one Si(5)O4 tetrahedra, and  an edgeedge with one Ca(1)O7 hexagonal pyramid. The corner-sharing octahedral tilt angles are 22°. In the second Si site, Si(2) is bonded to one O(13), one O(4), one O(7), and one O(9) atom to form SiO4 tetrahedra that share  a cornercorner with one Zr(1)O6 octahedra,  a cornercorner with one Si(1)O4 tetrahedra,  a cornercorner with one Si(3)O4 tetrahedra,  a cornercorner with one Si(6)O4 tetrahedra, and  an edgeedge with one Ca(1)O7 hexagonal pyramid. The corner-sharing octahedral tilt angles are 23°. In the third Si site, Si(3) is bonded to one O(10), one O(12), one O(4), and one O(6) atom to form SiO4 tetrahedra that share  a cornercorner with one Ca(1)O7 hexagonal pyramid,  a cornercorner with one Zr(1)O6 octahedra,  a cornercorner with one Si(2)O4 tetrahedra,  a cornercorner with one Si(4)O4 tetrahedra, and  a cornercorner with one Si(5)O4 tetrahedra. The corner-sharing octahedral tilt angles are 48°. In the fourth Si site, Si(4) is bonded to one O(10), one O(14), one O(3), and one O(8) atom to form SiO4 tetrahedra that share  a cornercorner with one Ca(1)O7 hexagonal pyramid,  a cornercorner with one Zr(1)O6 octahedra,  a cornercorner with one Si(1)O4 tetrahedra,  a cornercorner with one Si(3)O4 tetrahedra, and  a cornercorner with one Si(6)O4 tetrahedra. The corner-sharing octahedral tilt angles are 46°. In the fifth Si site, Si(5) is bonded to one O(1), one O(11), one O(12), and one O(16) atom to form SiO4 tetrahedra that share  a cornercorner with one Zr(1)O6 octahedra,  a cornercorner with one Si(1)O4 tetrahedra,  a cornercorner with one Si(3)O4 tetrahedra, and  a cornercorner with one Si(5)O4 tetrahedra. The corner-sharing octahedral tilt angles are 25°. In the sixth Si site, Si(6) is bonded to one O(13), one O(14), one O(15), and one O(2) atom to form SiO4 tetrahedra that share  a cornercorner with one Zr(1)O6 octahedra,  a cornercorner with one Si(2)O4 tetrahedra,  a cornercorner with one Si(4)O4 tetrahedra, and  a cornercorner with one Si(6)O4 tetrahedra. The corner-sharing octahedral tilt angles are 20°. There are eighteen inequivalent O sites. In the first O site, O(1) is bonded in a bent 150 degrees geometry to two equivalent Si(5) atoms. In the second O site, O(2) is bonded in a bent 150 degrees geometry to two equivalent Si(6) atoms. In the third O site, O(3) is bonded in a bent 150 degrees geometry to one Si(1) and one Si(4) atom. In the fourth O site, O(4) is bonded in a bent 150 degrees geometry to one Si(2) and one Si(3) atom. In the fifth O site, O(5) is bonded in a 3-coordinate geometry to one Ca(1), one Zr(1), and one Si(1) atom. In the sixth O site, O(6) is bonded in a distorted trigonal planar geometry to one Ca(1), one Zr(1), and one Si(3) atom. In the seventh O site, O(7) is bonded in a 3-coordinate geometry to one Ca(1), one Zr(1), and one Si(2) atom. In the eighth O site, O(8) is bonded in a 3-coordinate geometry to one Ca(1), one Zr(1), and one Si(4) atom. In the ninth O site, O(9) is bonded in a distorted T-shaped geometry to one Ca(1), one Si(1), and one Si(2) atom. In the tenth O site, O(10) is bonded in a bent 150 degrees geometry to one Si(3) and one Si(4) atom. In the eleventh O site, O(11) is bonded in a bent 150 degrees geometry to one Si(1) and one Si(5) atom. In the twelfth O site, O(12) is bonded in a bent 150 degrees geometry to one Si(3) and one Si(5) atom. In the thirteenth O site, O(13) is bonded in a bent 150 degrees geometry to one Si(2) and one Si(6) atom. In the fourteenth O site, O(14) is bonded in a bent 150 degrees geometry to one Si(4) and one Si(6) atom. In the fifteenth O site, O(15) is bonded in a bent 150 degrees geometry to one Zr(1) and one Si(6) atom. In the sixteenth O site, O(16) is bonded in a bent 150 degrees geometry to one Zr(1) and one Si(5) atom. In the seventeenth O site, O(17) is bonded in a single-bond geometry to one Ca(1) atom. In the eighteenth O site, O(18) is bonded in a single-bond geometry to one Ca(1) atom. is represented by the CIF card [CIF]
data_CaZrSi6O17
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   10.056
_cell_length_b   10.056
_cell_length_c   7.949
_cell_angle_alpha   76.320
_cell_angle_beta   76.320
_cell_angle_gamma   89.716
_symmetry_Int_Tables_number   1
_cell_volume   757.821
_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
  Ca  Ca0  1  0.989  0.496  0.958  1.0
  Ca  Ca1  1  0.504  0.011  0.042  1.0
  Zr  Zr2  1  0.249  0.254  0.995  1.0
  Zr  Zr3  1  0.746  0.751  0.005  1.0
  Si  Si4  1  0.052  0.329  0.656  1.0
  Si  Si5  1  0.671  0.948  0.344  1.0
  Si  Si6  1  0.820  0.557  0.660  1.0
  Si  Si7  1  0.443  0.180  0.340  1.0
  Si  Si8  1  0.978  0.709  0.270  1.0
  Si  Si9  1  0.291  0.022  0.730  1.0
  Si  Si10  1  0.202  0.492  0.270  1.0
  Si  Si11  1  0.508  0.798  0.730  1.0
  Si  Si12  1  0.989  0.023  0.695  1.0
  Si  Si13  1  0.977  0.011  0.305  1.0
  Si  Si14  1  0.511  0.495  0.699  1.0
  Si  Si15  1  0.505  0.489  0.301  1.0
  O  O16  1  0.010  0.990  0.500  1.0
  O  O17  1  0.487  0.513  0.500  1.0
  O  O18  1  0.152  0.375  0.456  1.0
  O  O19  1  0.625  0.848  0.544  1.0
  O  O20  1  0.862  0.655  0.459  1.0
  O  O21  1  0.345  0.138  0.541  1.0
  O  O22  1  0.131  0.329  0.812  1.0
  O  O23  1  0.671  0.869  0.188  1.0
  O  O24  1  0.919  0.678  0.107  1.0
  O  O25  1  0.322  0.081  0.893  1.0
  O  O26  1  0.824  0.639  0.813  1.0
  O  O27  1  0.361  0.176  0.187  1.0
  O  O28  1  0.172  0.429  0.108  1.0
  O  O29  1  0.571  0.828  0.892  1.0
  O  O30  1  0.937  0.444  0.690  1.0
  O  O31  1  0.556  0.063  0.310  1.0
  O  O32  1  0.116  0.627  0.286  1.0
  O  O33  1  0.373  0.884  0.714  1.0
  O  O34  1  0.970  0.186  0.680  1.0
  O  O35  1  0.814  0.030  0.320  1.0
  O  O36  1  0.016  0.871  0.237  1.0
  O  O37  1  0.129  0.984  0.763  1.0
  O  O38  1  0.675  0.474  0.693  1.0
  O  O39  1  0.526  0.325  0.307  1.0
  O  O40  1  0.364  0.530  0.238  1.0
  O  O41  1  0.470  0.636  0.762  1.0
  O  O42  1  0.418  0.368  0.839  1.0
  O  O43  1  0.632  0.582  0.161  1.0
  O  O44  1  0.858  0.934  0.839  1.0
  O  O45  1  0.066  0.142  0.161  1.0
  O  O46  1  0.920  0.307  0.221  1.0
  O  O47  1  0.693  0.080  0.779  1.0
  O  O48  1  0.189  0.643  0.898  1.0
  O  O49  1  0.357  0.811  0.102  1.0
[/CIF]
.