The compound described by KNaMg2Si4(O5F)2 crystallizes in the monoclinic C2/m space group. K(1) is bonded to four equivalent O(2) and eight equivalent O(3) atoms to form KO12 cuboctahedra that share edges with six equivalent K(1)O12 cuboctahedra and edges with twelve equivalent Si(1)O4 tetrahedra. Na(1) is bonded to four equivalent O(1) and two equivalent F(1) atoms to form NaO4F2 octahedra that share corners with four equivalent Si(1)O4 tetrahedra and edges with six equivalent Mg(1)O4F2 octahedra. Mg(1) is bonded to four equivalent O(1) and two equivalent F(1) atoms to form MgO4F2 octahedra that share corners with four equivalent Si(1)O4 tetrahedra, edges with three equivalent Na(1)O4F2 octahedra, and edges with three equivalent Mg(1)O4F2 octahedra. Si(1) is bonded to one O(1), one O(2), and two equivalent O(3) atoms to form SiO4 tetrahedra that share  a cornercorner with one Na(1)O4F2 octahedra, corners with two equivalent Mg(1)O4F2 octahedra, corners with three equivalent Si(1)O4 tetrahedra, and edges with three equivalent K(1)O12 cuboctahedra. The corner-sharing octahedral tilt angles range from 52-62°. There are three inequivalent O sites. In the first O site, O(1) is bonded in a rectangular see-saw-like geometry to one Na(1), two equivalent Mg(1), and one Si(1) atom. In the second O site, O(2) is bonded in a distorted bent 150 degrees geometry to two equivalent K(1) and two equivalent Si(1) atoms. In the third O site, O(3) is bonded in a distorted bent 120 degrees geometry to two equivalent K(1) and two equivalent Si(1) atoms. F(1) is bonded in a distorted T-shaped geometry to one Na(1) and two equivalent Mg(1) atoms. is represented by the CIF card [CIF]
data_KNaMg2Si4(O5F)2
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   5.310
_cell_length_b   5.310
_cell_length_c   10.429
_cell_angle_alpha   84.308
_cell_angle_beta   84.308
_cell_angle_gamma   119.491
_symmetry_Int_Tables_number   1
_cell_volume   250.906
_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
  K  K0  1  0.500  0.500  0.000  1.0
  Na  Na1  1  0.000  0.000  0.500  1.0
  Mg  Mg2  1  0.334  0.666  0.500  1.0
  Mg  Mg3  1  0.666  0.334  0.500  1.0
  Si  Si4  1  0.911  0.251  0.773  1.0
  Si  Si5  1  0.749  0.089  0.227  1.0
  Si  Si6  1  0.251  0.911  0.773  1.0
  Si  Si7  1  0.089  0.749  0.227  1.0
  O  O8  1  0.322  0.959  0.617  1.0
  O  O9  1  0.052  0.052  0.829  1.0
  O  O10  1  0.061  0.556  0.839  1.0
  O  O11  1  0.939  0.444  0.161  1.0
  O  O12  1  0.678  0.041  0.383  1.0
  O  O13  1  0.948  0.948  0.171  1.0
  O  O14  1  0.959  0.322  0.617  1.0
  O  O15  1  0.444  0.939  0.161  1.0
  O  O16  1  0.041  0.678  0.383  1.0
  O  O17  1  0.556  0.061  0.839  1.0
  F  F18  1  0.405  0.405  0.393  1.0
  F  F19  1  0.595  0.595  0.607  1.0
[/CIF]
.
The compound described by KNaMg2Si4(O5F)2 crystallizes in the monoclinic C2/m space group. K(1) is bonded to four equivalent O(2) and eight equivalent O(3) atoms to form KO12 cuboctahedra that share edges with six equivalent K(1)O12 cuboctahedra and edges with twelve equivalent Si(1)O4 tetrahedra. Na(1) is bonded to four equivalent O(1) and two equivalent F(1) atoms to form NaO4F2 octahedra that share corners with four equivalent Si(1)O4 tetrahedra and edges with six equivalent Mg(1)O4F2 octahedra. Mg(1) is bonded to four equivalent O(1) and two equivalent F(1) atoms to form MgO4F2 octahedra that share corners with four equivalent Si(1)O4 tetrahedra, edges with three equivalent Na(1)O4F2 octahedra, and edges with three equivalent Mg(1)O4F2 octahedra. Si(1) is bonded to one O(1), one O(2), and two equivalent O(3) atoms to form SiO4 tetrahedra that share  a cornercorner with one Na(1)O4F2 octahedra, corners with two equivalent Mg(1)O4F2 octahedra, corners with three equivalent Si(1)O4 tetrahedra, and edges with three equivalent K(1)O12 cuboctahedra. The corner-sharing octahedral tilt angles range from 52-62°. There are three inequivalent O sites. In the first O site, O(1) is bonded in a rectangular see-saw-like geometry to one Na(1), two equivalent Mg(1), and one Si(1) atom. In the second O site, O(2) is bonded in a distorted bent 150 degrees geometry to two equivalent K(1) and two equivalent Si(1) atoms. In the third O site, O(3) is bonded in a distorted bent 120 degrees geometry to two equivalent K(1) and two equivalent Si(1) atoms. F(1) is bonded in a distorted T-shaped geometry to one Na(1) and two equivalent Mg(1) atoms. is represented by the CIF card [CIF]
data_KNaMg2Si4(O5F)2
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   5.310
_cell_length_b   5.310
_cell_length_c   10.429
_cell_angle_alpha   84.308
_cell_angle_beta   84.308
_cell_angle_gamma   119.491
_symmetry_Int_Tables_number   1
_cell_volume   250.906
_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
  K  K0  1  0.500  0.500  0.000  1.0
  Na  Na1  1  0.000  0.000  0.500  1.0
  Mg  Mg2  1  0.334  0.666  0.500  1.0
  Mg  Mg3  1  0.666  0.334  0.500  1.0
  Si  Si4  1  0.911  0.251  0.773  1.0
  Si  Si5  1  0.749  0.089  0.227  1.0
  Si  Si6  1  0.251  0.911  0.773  1.0
  Si  Si7  1  0.089  0.749  0.227  1.0
  O  O8  1  0.322  0.959  0.617  1.0
  O  O9  1  0.052  0.052  0.829  1.0
  O  O10  1  0.061  0.556  0.839  1.0
  O  O11  1  0.939  0.444  0.161  1.0
  O  O12  1  0.678  0.041  0.383  1.0
  O  O13  1  0.948  0.948  0.171  1.0
  O  O14  1  0.959  0.322  0.617  1.0
  O  O15  1  0.444  0.939  0.161  1.0
  O  O16  1  0.041  0.678  0.383  1.0
  O  O17  1  0.556  0.061  0.839  1.0
  F  F18  1  0.405  0.405  0.393  1.0
  F  F19  1  0.595  0.595  0.607  1.0
[/CIF]
.