The material structure described by NaCa2Si3O8(OH) is Esseneite-derived structured and crystallizes in the triclinic P-1 space group. Na(1) is bonded in a 7-coordinate geometry to one H(1), one O(1), one O(2), one O(3), one O(6), one O(8), and one O(9) atom. There are two inequivalent Ca sites. In the first Ca site, Ca(1) is bonded to one O(4), one O(7), one O(8), one O(9), and two equivalent O(5) atoms to form CaO6 octahedra that share  a cornercorner with one Si(2)O4 tetrahedra, corners with two equivalent Si(1)O4 tetrahedra, corners with three equivalent Si(3)O4 tetrahedra,  an edgeedge with one Ca(1)O6 octahedra, and edges with three equivalent Ca(2)O6 octahedra. In the second Ca site, Ca(2) is bonded to one O(5), one O(6), one O(7), one O(8), and two equivalent O(4) atoms to form CaO6 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 Ca(2)O6 octahedra, and edges with three equivalent Ca(1)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(7), and one O(8) atom to form SiO4 tetrahedra that share corners with two equivalent Ca(1)O6 octahedra, corners with two equivalent Ca(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 48-59°. In the second Si site, Si(2) is bonded to one O(1), one O(3), one O(4), and one O(6) atom to form SiO4 tetrahedra that share  a cornercorner with one Ca(1)O6 octahedra, corners with three equivalent Ca(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 40-66°. In the third Si site, Si(3) is bonded to one O(2), one O(3), one O(5), and one O(9) atom to form SiO4 tetrahedra that share  a cornercorner with one Ca(2)O6 octahedra, corners with three equivalent Ca(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 39-66°. H(1) is bonded in a distorted linear geometry to one Na(1), one O(6), and one O(9) atom. There are nine inequivalent O sites. In the first O site, O(1) is bonded in a 3-coordinate geometry to one Na(1), one Si(1), and one Si(2) atom. In the second O site, O(2) is bonded in a 3-coordinate geometry to one Na(1), one Si(1), and one Si(3) atom. In the third O site, O(3) is bonded in a distorted T-shaped geometry to one Na(1), one Si(2), and one Si(3) atom. In the fourth O site, O(4) is bonded to one Ca(1), two equivalent Ca(2), and one Si(2) atom to form a mixture of distorted corner and edge-sharing OCa3Si tetrahedra. In the fifth O site, O(5) is bonded to one Ca(2), two equivalent Ca(1), and one Si(3) atom to form a mixture of distorted corner and edge-sharing OCa3Si tetrahedra. In the sixth O site, O(6) is bonded in a 4-coordinate geometry to one Na(1), one Ca(2), one Si(2), and one H(1) atom. In the seventh O site, O(7) is bonded in a distorted trigonal planar geometry to one Ca(1), one Ca(2), and one Si(1) atom. In the eighth O site, O(8) is bonded in a distorted rectangular see-saw-like geometry to one Na(1), one Ca(1), one Ca(2), and one Si(1) atom. In the ninth O site, O(9) is bonded in a 2-coordinate geometry to one Na(1), one Ca(1), one Si(3), and one H(1) atom. is represented by the Crystallographic Information File (CIF) [CIF]
data_NaCa2Si3HO9
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   7.090
_cell_length_b   7.116
_cell_length_c   8.086
_cell_angle_alpha   95.220
_cell_angle_beta   102.411
_cell_angle_gamma   90.449
_symmetry_Int_Tables_number   1
_cell_volume   396.627
_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  0.745  0.660  0.449  1.0
  Na  Na1  1  0.255  0.340  0.551  1.0
  Ca  Ca2  1  0.594  0.142  0.854  1.0
  Ca  Ca3  1  0.406  0.858  0.146  1.0
  Ca  Ca4  1  0.916  0.857  0.154  1.0
  Ca  Ca5  1  0.084  0.143  0.846  1.0
  Si  Si6  1  0.735  0.144  0.449  1.0
  Si  Si7  1  0.049  0.656  0.786  1.0
  Si  Si8  1  0.600  0.664  0.782  1.0
  Si  Si9  1  0.400  0.336  0.218  1.0
  Si  Si10  1  0.265  0.856  0.551  1.0
  Si  Si11  1  0.951  0.344  0.214  1.0
  H  H12  1  0.638  0.531  0.166  1.0
  H  H13  1  0.362  0.469  0.834  1.0
  O  O14  1  0.091  0.728  0.605  1.0
  O  O15  1  0.909  0.272  0.395  1.0
  O  O16  1  0.467  0.729  0.602  1.0
  O  O17  1  0.533  0.271  0.398  1.0
  O  O18  1  0.811  0.615  0.737  1.0
  O  O19  1  0.189  0.385  0.263  1.0
  O  O20  1  0.105  0.823  0.941  1.0
  O  O21  1  0.895  0.177  0.059  1.0
  O  O22  1  0.614  0.827  0.938  1.0
  O  O23  1  0.386  0.173  0.062  1.0
  O  O24  1  0.156  0.459  0.819  1.0
  O  O25  1  0.844  0.541  0.181  1.0
  O  O26  1  0.213  0.872  0.348  1.0
  O  O27  1  0.787  0.128  0.652  1.0
  O  O28  1  0.703  0.945  0.330  1.0
  O  O29  1  0.297  0.055  0.670  1.0
  O  O30  1  0.494  0.540  0.187  1.0
  O  O31  1  0.506  0.460  0.813  1.0
[/CIF]
.
The material structure described by NaCa2Si3O8(OH) is Esseneite-derived structured and crystallizes in the triclinic P-1 space group. Na(1) is bonded in a 7-coordinate geometry to one H(1), one O(1), one O(2), one O(3), one O(6), one O(8), and one O(9) atom. There are two inequivalent Ca sites. In the first Ca site, Ca(1) is bonded to one O(4), one O(7), one O(8), one O(9), and two equivalent O(5) atoms to form CaO6 octahedra that share  a cornercorner with one Si(2)O4 tetrahedra, corners with two equivalent Si(1)O4 tetrahedra, corners with three equivalent Si(3)O4 tetrahedra,  an edgeedge with one Ca(1)O6 octahedra, and edges with three equivalent Ca(2)O6 octahedra. In the second Ca site, Ca(2) is bonded to one O(5), one O(6), one O(7), one O(8), and two equivalent O(4) atoms to form CaO6 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 Ca(2)O6 octahedra, and edges with three equivalent Ca(1)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(7), and one O(8) atom to form SiO4 tetrahedra that share corners with two equivalent Ca(1)O6 octahedra, corners with two equivalent Ca(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 48-59°. In the second Si site, Si(2) is bonded to one O(1), one O(3), one O(4), and one O(6) atom to form SiO4 tetrahedra that share  a cornercorner with one Ca(1)O6 octahedra, corners with three equivalent Ca(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 40-66°. In the third Si site, Si(3) is bonded to one O(2), one O(3), one O(5), and one O(9) atom to form SiO4 tetrahedra that share  a cornercorner with one Ca(2)O6 octahedra, corners with three equivalent Ca(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 39-66°. H(1) is bonded in a distorted linear geometry to one Na(1), one O(6), and one O(9) atom. There are nine inequivalent O sites. In the first O site, O(1) is bonded in a 3-coordinate geometry to one Na(1), one Si(1), and one Si(2) atom. In the second O site, O(2) is bonded in a 3-coordinate geometry to one Na(1), one Si(1), and one Si(3) atom. In the third O site, O(3) is bonded in a distorted T-shaped geometry to one Na(1), one Si(2), and one Si(3) atom. In the fourth O site, O(4) is bonded to one Ca(1), two equivalent Ca(2), and one Si(2) atom to form a mixture of distorted corner and edge-sharing OCa3Si tetrahedra. In the fifth O site, O(5) is bonded to one Ca(2), two equivalent Ca(1), and one Si(3) atom to form a mixture of distorted corner and edge-sharing OCa3Si tetrahedra. In the sixth O site, O(6) is bonded in a 4-coordinate geometry to one Na(1), one Ca(2), one Si(2), and one H(1) atom. In the seventh O site, O(7) is bonded in a distorted trigonal planar geometry to one Ca(1), one Ca(2), and one Si(1) atom. In the eighth O site, O(8) is bonded in a distorted rectangular see-saw-like geometry to one Na(1), one Ca(1), one Ca(2), and one Si(1) atom. In the ninth O site, O(9) is bonded in a 2-coordinate geometry to one Na(1), one Ca(1), one Si(3), and one H(1) atom. is represented by the Crystallographic Information File (CIF) [CIF]
data_NaCa2Si3HO9
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   7.090
_cell_length_b   7.116
_cell_length_c   8.086
_cell_angle_alpha   95.220
_cell_angle_beta   102.411
_cell_angle_gamma   90.449
_symmetry_Int_Tables_number   1
_cell_volume   396.627
_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  0.745  0.660  0.449  1.0
  Na  Na1  1  0.255  0.340  0.551  1.0
  Ca  Ca2  1  0.594  0.142  0.854  1.0
  Ca  Ca3  1  0.406  0.858  0.146  1.0
  Ca  Ca4  1  0.916  0.857  0.154  1.0
  Ca  Ca5  1  0.084  0.143  0.846  1.0
  Si  Si6  1  0.735  0.144  0.449  1.0
  Si  Si7  1  0.049  0.656  0.786  1.0
  Si  Si8  1  0.600  0.664  0.782  1.0
  Si  Si9  1  0.400  0.336  0.218  1.0
  Si  Si10  1  0.265  0.856  0.551  1.0
  Si  Si11  1  0.951  0.344  0.214  1.0
  H  H12  1  0.638  0.531  0.166  1.0
  H  H13  1  0.362  0.469  0.834  1.0
  O  O14  1  0.091  0.728  0.605  1.0
  O  O15  1  0.909  0.272  0.395  1.0
  O  O16  1  0.467  0.729  0.602  1.0
  O  O17  1  0.533  0.271  0.398  1.0
  O  O18  1  0.811  0.615  0.737  1.0
  O  O19  1  0.189  0.385  0.263  1.0
  O  O20  1  0.105  0.823  0.941  1.0
  O  O21  1  0.895  0.177  0.059  1.0
  O  O22  1  0.614  0.827  0.938  1.0
  O  O23  1  0.386  0.173  0.062  1.0
  O  O24  1  0.156  0.459  0.819  1.0
  O  O25  1  0.844  0.541  0.181  1.0
  O  O26  1  0.213  0.872  0.348  1.0
  O  O27  1  0.787  0.128  0.652  1.0
  O  O28  1  0.703  0.945  0.330  1.0
  O  O29  1  0.297  0.055  0.670  1.0
  O  O30  1  0.494  0.540  0.187  1.0
  O  O31  1  0.506  0.460  0.813  1.0
[/CIF]
.