The material structure described by KBaYSi2O7 crystallizes in the monoclinic P2_1/c space group. K(1) is bonded in a 9-coordinate geometry to one O(1), one O(3), one O(6), one O(7), two equivalent O(5), and three equivalent O(4) atoms. Ba(1) is bonded in a 9-coordinate geometry to one O(3), one O(6), two equivalent O(1), two equivalent O(7), and three equivalent O(2) atoms. Y(1) is bonded to one O(1), one O(2), one O(3), one O(4), one O(6), and one O(7) atom to form YO6 octahedra that share corners with three equivalent Si(1)O4 tetrahedra and corners with three equivalent Si(2)O4 tetrahedra. There are two inequivalent Si sites. In the first Si site, Si(1) is bonded to one O(2), one O(3), one O(5), and one O(6) atom to form SiO4 tetrahedra that share corners with three equivalent Y(1)O6 octahedra and  a cornercorner with one Si(2)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 20-47°. In the second Si site, Si(2) is bonded to one O(1), one O(4), one O(5), and one O(7) atom to form SiO4 tetrahedra that share corners with three equivalent Y(1)O6 octahedra and  a cornercorner with one Si(1)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 10-48°. There are seven inequivalent O sites. In the first O site, O(7) is bonded in a 5-coordinate geometry to one K(1), two equivalent Ba(1), one Y(1), and one Si(2) atom. In the second O site, O(1) is bonded in a 5-coordinate geometry to one K(1), two equivalent Ba(1), one Y(1), and one Si(2) atom. In the third O site, O(2) is bonded in a 5-coordinate geometry to three equivalent Ba(1), one Y(1), and one Si(1) atom. In the fourth O site, O(3) is bonded in a 3-coordinate geometry to one K(1), one Ba(1), one Y(1), and one Si(1) atom. In the fifth O site, O(4) is bonded in a 2-coordinate geometry to three equivalent K(1), one Y(1), and one Si(2) atom. In the sixth O site, O(5) is bonded in a distorted bent 120 degrees geometry to two equivalent K(1), one Si(1), and one Si(2) atom. In the seventh O site, O(6) is bonded in a 2-coordinate geometry to one K(1), one Ba(1), one Y(1), and one Si(1) atom. is represented by the Crystallographic Information File (CIF) [CIF]
data_KBaYSi2O7
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   5.787
_cell_length_b   9.886
_cell_length_c   14.405
_cell_angle_alpha   63.005
_cell_angle_beta   90.000
_cell_angle_gamma   90.000
_symmetry_Int_Tables_number   1
_cell_volume   734.322
_cell_formula_units_Z   4
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  0.764  0.007  0.362  1.0
  K  K1  1  0.264  0.993  0.138  1.0
  K  K2  1  0.736  0.007  0.862  1.0
  K  K3  1  0.236  0.993  0.638  1.0
  Ba  Ba4  1  0.269  0.535  0.328  1.0
  Ba  Ba5  1  0.231  0.535  0.828  1.0
  Ba  Ba6  1  0.731  0.465  0.672  1.0
  Ba  Ba7  1  0.769  0.465  0.172  1.0
  Y  Y8  1  0.240  0.739  0.021  1.0
  Y  Y9  1  0.760  0.261  0.979  1.0
  Y  Y10  1  0.260  0.739  0.521  1.0
  Y  Y11  1  0.740  0.261  0.479  1.0
  Si  Si12  1  0.228  0.326  0.621  1.0
  Si  Si13  1  0.745  0.829  0.646  1.0
  Si  Si14  1  0.255  0.171  0.354  1.0
  Si  Si15  1  0.755  0.829  0.146  1.0
  Si  Si16  1  0.772  0.674  0.379  1.0
  Si  Si17  1  0.728  0.674  0.879  1.0
  Si  Si18  1  0.245  0.171  0.854  1.0
  Si  Si19  1  0.272  0.326  0.121  1.0
  O  O20  1  0.999  0.258  0.849  1.0
  O  O21  1  0.242  0.480  0.638  1.0
  O  O22  1  0.465  0.701  0.908  1.0
  O  O23  1  0.760  0.009  0.065  1.0
  O  O24  1  0.742  0.520  0.862  1.0
  O  O25  1  0.535  0.299  0.092  1.0
  O  O26  1  0.501  0.258  0.349  1.0
  O  O27  1  0.797  0.822  0.764  1.0
  O  O28  1  0.581  0.677  0.461  1.0
  O  O29  1  0.260  0.991  0.435  1.0
  O  O30  1  0.703  0.822  0.264  1.0
  O  O31  1  0.499  0.742  0.651  1.0
  O  O32  1  0.297  0.178  0.736  1.0
  O  O33  1  0.081  0.323  0.039  1.0
  O  O34  1  0.462  0.264  0.873  1.0
  O  O35  1  0.962  0.736  0.627  1.0
  O  O36  1  0.035  0.701  0.408  1.0
  O  O37  1  0.965  0.299  0.592  1.0
  O  O38  1  0.919  0.677  0.961  1.0
  O  O39  1  0.538  0.736  0.127  1.0
  O  O40  1  0.203  0.178  0.236  1.0
  O  O41  1  0.038  0.264  0.373  1.0
  O  O42  1  0.001  0.742  0.151  1.0
  O  O43  1  0.419  0.323  0.539  1.0
  O  O44  1  0.258  0.480  0.138  1.0
  O  O45  1  0.758  0.520  0.362  1.0
  O  O46  1  0.740  0.009  0.565  1.0
  O  O47  1  0.240  0.991  0.935  1.0
[/CIF]
.
The material structure described by KBaYSi2O7 crystallizes in the monoclinic P2_1/c space group. K(1) is bonded in a 9-coordinate geometry to one O(1), one O(3), one O(6), one O(7), two equivalent O(5), and three equivalent O(4) atoms. Ba(1) is bonded in a 9-coordinate geometry to one O(3), one O(6), two equivalent O(1), two equivalent O(7), and three equivalent O(2) atoms. Y(1) is bonded to one O(1), one O(2), one O(3), one O(4), one O(6), and one O(7) atom to form YO6 octahedra that share corners with three equivalent Si(1)O4 tetrahedra and corners with three equivalent Si(2)O4 tetrahedra. There are two inequivalent Si sites. In the first Si site, Si(1) is bonded to one O(2), one O(3), one O(5), and one O(6) atom to form SiO4 tetrahedra that share corners with three equivalent Y(1)O6 octahedra and  a cornercorner with one Si(2)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 20-47°. In the second Si site, Si(2) is bonded to one O(1), one O(4), one O(5), and one O(7) atom to form SiO4 tetrahedra that share corners with three equivalent Y(1)O6 octahedra and  a cornercorner with one Si(1)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 10-48°. There are seven inequivalent O sites. In the first O site, O(7) is bonded in a 5-coordinate geometry to one K(1), two equivalent Ba(1), one Y(1), and one Si(2) atom. In the second O site, O(1) is bonded in a 5-coordinate geometry to one K(1), two equivalent Ba(1), one Y(1), and one Si(2) atom. In the third O site, O(2) is bonded in a 5-coordinate geometry to three equivalent Ba(1), one Y(1), and one Si(1) atom. In the fourth O site, O(3) is bonded in a 3-coordinate geometry to one K(1), one Ba(1), one Y(1), and one Si(1) atom. In the fifth O site, O(4) is bonded in a 2-coordinate geometry to three equivalent K(1), one Y(1), and one Si(2) atom. In the sixth O site, O(5) is bonded in a distorted bent 120 degrees geometry to two equivalent K(1), one Si(1), and one Si(2) atom. In the seventh O site, O(6) is bonded in a 2-coordinate geometry to one K(1), one Ba(1), one Y(1), and one Si(1) atom. is represented by the Crystallographic Information File (CIF) [CIF]
data_KBaYSi2O7
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   5.787
_cell_length_b   9.886
_cell_length_c   14.405
_cell_angle_alpha   63.005
_cell_angle_beta   90.000
_cell_angle_gamma   90.000
_symmetry_Int_Tables_number   1
_cell_volume   734.322
_cell_formula_units_Z   4
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  0.764  0.007  0.362  1.0
  K  K1  1  0.264  0.993  0.138  1.0
  K  K2  1  0.736  0.007  0.862  1.0
  K  K3  1  0.236  0.993  0.638  1.0
  Ba  Ba4  1  0.269  0.535  0.328  1.0
  Ba  Ba5  1  0.231  0.535  0.828  1.0
  Ba  Ba6  1  0.731  0.465  0.672  1.0
  Ba  Ba7  1  0.769  0.465  0.172  1.0
  Y  Y8  1  0.240  0.739  0.021  1.0
  Y  Y9  1  0.760  0.261  0.979  1.0
  Y  Y10  1  0.260  0.739  0.521  1.0
  Y  Y11  1  0.740  0.261  0.479  1.0
  Si  Si12  1  0.228  0.326  0.621  1.0
  Si  Si13  1  0.745  0.829  0.646  1.0
  Si  Si14  1  0.255  0.171  0.354  1.0
  Si  Si15  1  0.755  0.829  0.146  1.0
  Si  Si16  1  0.772  0.674  0.379  1.0
  Si  Si17  1  0.728  0.674  0.879  1.0
  Si  Si18  1  0.245  0.171  0.854  1.0
  Si  Si19  1  0.272  0.326  0.121  1.0
  O  O20  1  0.999  0.258  0.849  1.0
  O  O21  1  0.242  0.480  0.638  1.0
  O  O22  1  0.465  0.701  0.908  1.0
  O  O23  1  0.760  0.009  0.065  1.0
  O  O24  1  0.742  0.520  0.862  1.0
  O  O25  1  0.535  0.299  0.092  1.0
  O  O26  1  0.501  0.258  0.349  1.0
  O  O27  1  0.797  0.822  0.764  1.0
  O  O28  1  0.581  0.677  0.461  1.0
  O  O29  1  0.260  0.991  0.435  1.0
  O  O30  1  0.703  0.822  0.264  1.0
  O  O31  1  0.499  0.742  0.651  1.0
  O  O32  1  0.297  0.178  0.736  1.0
  O  O33  1  0.081  0.323  0.039  1.0
  O  O34  1  0.462  0.264  0.873  1.0
  O  O35  1  0.962  0.736  0.627  1.0
  O  O36  1  0.035  0.701  0.408  1.0
  O  O37  1  0.965  0.299  0.592  1.0
  O  O38  1  0.919  0.677  0.961  1.0
  O  O39  1  0.538  0.736  0.127  1.0
  O  O40  1  0.203  0.178  0.236  1.0
  O  O41  1  0.038  0.264  0.373  1.0
  O  O42  1  0.001  0.742  0.151  1.0
  O  O43  1  0.419  0.323  0.539  1.0
  O  O44  1  0.258  0.480  0.138  1.0
  O  O45  1  0.758  0.520  0.362  1.0
  O  O46  1  0.740  0.009  0.565  1.0
  O  O47  1  0.240  0.991  0.935  1.0
[/CIF]
.