The crystal structure described by MgNb3SiO10 crystallizes in the triclinic P1 space group. Mg(1) is bonded to one O(2), one O(3), one O(5), one O(6), one O(7), and one O(8) atom to form distorted MgO6 pentagonal pyramids that share  a cornercorner with one Nb(1)O6 octahedra, corners with two equivalent Si(1)O4 tetrahedra, edges with two equivalent Nb(2)O6 octahedra,  an edgeedge with one Nb(3)O5 trigonal bipyramid, and  a faceface with one Nb(1)O6 octahedra. The corner-sharing octahedral tilt angles are 62°. There are three inequivalent Nb sites. In the first Nb site, Nb(1) is bonded to one O(1), one O(3), one O(4), one O(5), one O(6), and one O(8) atom to form distorted NbO6 octahedra that share corners with four equivalent Nb(2)O6 octahedra,  a cornercorner with one Mg(1)O6 pentagonal pyramid,  a cornercorner with one Si(1)O4 tetrahedra, corners with two equivalent Nb(3)O5 trigonal bipyramids, and  a faceface with one Mg(1)O6 pentagonal pyramid. The corner-sharing octahedral tilt angles range from 19-45°. In the second Nb site, Nb(2) is bonded to one O(10), one O(3), one O(4), one O(5), one O(6), and one O(7) atom to form NbO6 octahedra that share corners with four equivalent Nb(1)O6 octahedra,  a cornercorner with one Si(1)O4 tetrahedra, edges with two equivalent Mg(1)O6 pentagonal pyramids, and  an edgeedge with one Nb(3)O5 trigonal bipyramid. The corner-sharing octahedral tilt angles range from 19-45°. In the third Nb site, Nb(3) is bonded to one O(10), one O(2), one O(4), one O(8), and one O(9) atom to form distorted NbO5 trigonal bipyramids that share corners with two equivalent Nb(1)O6 octahedra, corners with two equivalent Si(1)O4 tetrahedra,  an edgeedge with one Nb(2)O6 octahedra, and  an edgeedge with one Mg(1)O6 pentagonal pyramid. The corner-sharing octahedral tilt angles range from 35-50°. Si(1) is bonded to one O(1), one O(2), one O(7), and one O(9) atom to form SiO4 tetrahedra that share  a cornercorner with one Nb(1)O6 octahedra,  a cornercorner with one Nb(2)O6 octahedra, corners with two equivalent Mg(1)O6 pentagonal pyramids, and corners with two equivalent Nb(3)O5 trigonal bipyramids. The corner-sharing octahedral tilt angles range from 48-56°. There are ten inequivalent O sites. In the first O site, O(1) is bonded in a distorted bent 120 degrees geometry to one Nb(1) and one Si(1) atom. In the second O site, O(2) is bonded in a distorted trigonal planar geometry to one Mg(1), one Nb(3), and one Si(1) atom. In the third O site, O(3) is bonded in a distorted trigonal planar geometry to one Mg(1), one Nb(1), and one Nb(2) atom. In the fourth O site, O(4) is bonded in a distorted T-shaped geometry to one Nb(1), one Nb(2), and one Nb(3) atom. In the fifth O site, O(5) is bonded in a distorted T-shaped geometry to one Mg(1), one Nb(1), and one Nb(2) atom. In the sixth O site, O(6) is bonded in a T-shaped geometry to one Mg(1), one Nb(1), and one Nb(2) atom. In the seventh O site, O(7) is bonded in a distorted trigonal planar geometry to one Mg(1), one Nb(2), and one Si(1) atom. In the eighth O site, O(8) is bonded in a T-shaped geometry to one Mg(1), one Nb(1), and one Nb(3) atom. In the ninth O site, O(9) is bonded in a bent 150 degrees geometry to one Nb(3) and one Si(1) atom. In the tenth O site, O(10) is bonded in a water-like geometry to one Nb(2) and one Nb(3) atom. is represented by the CIF file [CIF]
data_MgNb3SiO10
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   5.430
_cell_length_b   5.603
_cell_length_c   7.390
_cell_angle_alpha   107.932
_cell_angle_beta   110.370
_cell_angle_gamma   89.562
_symmetry_Int_Tables_number   1
_cell_volume   199.295
_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
  Mg  Mg0  1  0.748  0.347  0.936  1.0
  Nb  Nb1  1  0.608  0.700  0.700  1.0
  Nb  Nb2  1  0.130  0.202  0.705  1.0
  Nb  Nb3  1  0.766  0.849  0.279  1.0
  Si  Si4  1  0.399  0.331  0.215  1.0
  O  O5  1  0.361  0.536  0.411  1.0
  O  O6  1  0.649  0.463  0.185  1.0
  O  O7  1  0.477  0.025  0.793  1.0
  O  O8  1  0.837  0.858  0.582  1.0
  O  O9  1  0.365  0.484  0.759  1.0
  O  O10  1  0.830  0.399  0.692  1.0
  O  O11  1  0.131  0.265  0.009  1.0
  O  O12  1  0.807  0.757  0.019  1.0
  O  O13  1  0.494  0.060  0.246  1.0
  O  O14  1  0.091  0.063  0.415  1.0
[/CIF]
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The crystal structure described by MgNb3SiO10 crystallizes in the triclinic P1 space group. Mg(1) is bonded to one O(2), one O(3), one O(5), one O(6), one O(7), and one O(8) atom to form distorted MgO6 pentagonal pyramids that share  a cornercorner with one Nb(1)O6 octahedra, corners with two equivalent Si(1)O4 tetrahedra, edges with two equivalent Nb(2)O6 octahedra,  an edgeedge with one Nb(3)O5 trigonal bipyramid, and  a faceface with one Nb(1)O6 octahedra. The corner-sharing octahedral tilt angles are 62°. There are three inequivalent Nb sites. In the first Nb site, Nb(1) is bonded to one O(1), one O(3), one O(4), one O(5), one O(6), and one O(8) atom to form distorted NbO6 octahedra that share corners with four equivalent Nb(2)O6 octahedra,  a cornercorner with one Mg(1)O6 pentagonal pyramid,  a cornercorner with one Si(1)O4 tetrahedra, corners with two equivalent Nb(3)O5 trigonal bipyramids, and  a faceface with one Mg(1)O6 pentagonal pyramid. The corner-sharing octahedral tilt angles range from 19-45°. In the second Nb site, Nb(2) is bonded to one O(10), one O(3), one O(4), one O(5), one O(6), and one O(7) atom to form NbO6 octahedra that share corners with four equivalent Nb(1)O6 octahedra,  a cornercorner with one Si(1)O4 tetrahedra, edges with two equivalent Mg(1)O6 pentagonal pyramids, and  an edgeedge with one Nb(3)O5 trigonal bipyramid. The corner-sharing octahedral tilt angles range from 19-45°. In the third Nb site, Nb(3) is bonded to one O(10), one O(2), one O(4), one O(8), and one O(9) atom to form distorted NbO5 trigonal bipyramids that share corners with two equivalent Nb(1)O6 octahedra, corners with two equivalent Si(1)O4 tetrahedra,  an edgeedge with one Nb(2)O6 octahedra, and  an edgeedge with one Mg(1)O6 pentagonal pyramid. The corner-sharing octahedral tilt angles range from 35-50°. Si(1) is bonded to one O(1), one O(2), one O(7), and one O(9) atom to form SiO4 tetrahedra that share  a cornercorner with one Nb(1)O6 octahedra,  a cornercorner with one Nb(2)O6 octahedra, corners with two equivalent Mg(1)O6 pentagonal pyramids, and corners with two equivalent Nb(3)O5 trigonal bipyramids. The corner-sharing octahedral tilt angles range from 48-56°. There are ten inequivalent O sites. In the first O site, O(1) is bonded in a distorted bent 120 degrees geometry to one Nb(1) and one Si(1) atom. In the second O site, O(2) is bonded in a distorted trigonal planar geometry to one Mg(1), one Nb(3), and one Si(1) atom. In the third O site, O(3) is bonded in a distorted trigonal planar geometry to one Mg(1), one Nb(1), and one Nb(2) atom. In the fourth O site, O(4) is bonded in a distorted T-shaped geometry to one Nb(1), one Nb(2), and one Nb(3) atom. In the fifth O site, O(5) is bonded in a distorted T-shaped geometry to one Mg(1), one Nb(1), and one Nb(2) atom. In the sixth O site, O(6) is bonded in a T-shaped geometry to one Mg(1), one Nb(1), and one Nb(2) atom. In the seventh O site, O(7) is bonded in a distorted trigonal planar geometry to one Mg(1), one Nb(2), and one Si(1) atom. In the eighth O site, O(8) is bonded in a T-shaped geometry to one Mg(1), one Nb(1), and one Nb(3) atom. In the ninth O site, O(9) is bonded in a bent 150 degrees geometry to one Nb(3) and one Si(1) atom. In the tenth O site, O(10) is bonded in a water-like geometry to one Nb(2) and one Nb(3) atom. is represented by the CIF file [CIF]
data_MgNb3SiO10
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   5.430
_cell_length_b   5.603
_cell_length_c   7.390
_cell_angle_alpha   107.932
_cell_angle_beta   110.370
_cell_angle_gamma   89.562
_symmetry_Int_Tables_number   1
_cell_volume   199.295
_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
  Mg  Mg0  1  0.748  0.347  0.936  1.0
  Nb  Nb1  1  0.608  0.700  0.700  1.0
  Nb  Nb2  1  0.130  0.202  0.705  1.0
  Nb  Nb3  1  0.766  0.849  0.279  1.0
  Si  Si4  1  0.399  0.331  0.215  1.0
  O  O5  1  0.361  0.536  0.411  1.0
  O  O6  1  0.649  0.463  0.185  1.0
  O  O7  1  0.477  0.025  0.793  1.0
  O  O8  1  0.837  0.858  0.582  1.0
  O  O9  1  0.365  0.484  0.759  1.0
  O  O10  1  0.830  0.399  0.692  1.0
  O  O11  1  0.131  0.265  0.009  1.0
  O  O12  1  0.807  0.757  0.019  1.0
  O  O13  1  0.494  0.060  0.246  1.0
  O  O14  1  0.091  0.063  0.415  1.0
[/CIF]
.