The structure described by Eu2SiO5 crystallizes in the orthorhombic Pnma space group. There are two inequivalent Eu sites. In the first Eu site, Eu(1) is bonded in a 7-coordinate geometry to one O(1), one O(3), one O(4), two equivalent O(2), and two equivalent O(5) atoms. In the second Eu site, Eu(2) is bonded in a 7-coordinate geometry to one O(4), one O(5), two equivalent O(3), and three equivalent O(1) atoms. Si(1) is bonded to one O(2), one O(3), one O(5), and two equivalent O(4) atoms to form distorted corner-sharing SiO5 trigonal bipyramids. There are five inequivalent O sites. In the first O site, O(1) is bonded to one Eu(1) and three equivalent Eu(2) atoms to form OEu4 tetrahedra that share corners with two equivalent O(1)Eu4 tetrahedra, corners with five equivalent O(3)Eu3Si tetrahedra, corners with five equivalent O(5)Eu3Si tetrahedra,  an edgeedge with one O(3)Eu3Si tetrahedra, and edges with two equivalent O(1)Eu4 tetrahedra. In the second O site, O(2) is bonded in a distorted trigonal planar geometry to two equivalent Eu(1) and one Si(1) atom. In the third O site, O(3) is bonded to one Eu(1), two equivalent Eu(2), and one Si(1) atom to form distorted OEu3Si tetrahedra that share  a cornercorner with one O(5)Eu3Si tetrahedra, corners with two equivalent O(3)Eu3Si tetrahedra, corners with five equivalent O(1)Eu4 tetrahedra,  an edgeedge with one O(1)Eu4 tetrahedra, and edges with two equivalent O(5)Eu3Si tetrahedra. In the fourth O site, O(4) is bonded in a 4-coordinate geometry to one Eu(1), one Eu(2), and two equivalent Si(1) atoms. In the fifth O site, O(5) is bonded to one Eu(2), two equivalent Eu(1), and one Si(1) atom to form distorted OEu3Si tetrahedra that share  a cornercorner with one O(3)Eu3Si tetrahedra, corners with two equivalent O(5)Eu3Si tetrahedra, corners with five equivalent O(1)Eu4 tetrahedra, and edges with two equivalent O(3)Eu3Si tetrahedra. is represented by the CIF file [CIF]
data_Eu2SiO5
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   3.746
_cell_length_b   10.654
_cell_length_c   10.980
_cell_angle_alpha   90.000
_cell_angle_beta   90.000
_cell_angle_gamma   90.000
_symmetry_Int_Tables_number   1
_cell_volume   438.252
_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
  Eu  Eu0  1  0.250  0.095  0.289  1.0
  Eu  Eu1  1  0.250  0.135  0.942  1.0
  Eu  Eu2  1  0.750  0.365  0.442  1.0
  Eu  Eu3  1  0.750  0.405  0.789  1.0
  Eu  Eu4  1  0.250  0.595  0.211  1.0
  Eu  Eu5  1  0.250  0.635  0.558  1.0
  Eu  Eu6  1  0.750  0.865  0.058  1.0
  Eu  Eu7  1  0.750  0.905  0.711  1.0
  Si  Si8  1  0.250  0.182  0.626  1.0
  Si  Si9  1  0.750  0.318  0.126  1.0
  Si  Si10  1  0.250  0.682  0.874  1.0
  Si  Si11  1  0.750  0.818  0.374  1.0
  O  O12  1  0.750  0.009  0.897  1.0
  O  O13  1  0.250  0.032  0.656  1.0
  O  O14  1  0.250  0.224  0.478  1.0
  O  O15  1  0.750  0.216  0.623  1.0
  O  O16  1  0.750  0.231  0.256  1.0
  O  O17  1  0.250  0.269  0.756  1.0
  O  O18  1  0.250  0.284  0.123  1.0
  O  O19  1  0.750  0.276  0.978  1.0
  O  O20  1  0.750  0.468  0.156  1.0
  O  O21  1  0.250  0.491  0.397  1.0
  O  O22  1  0.750  0.509  0.603  1.0
  O  O23  1  0.250  0.532  0.844  1.0
  O  O24  1  0.250  0.724  0.022  1.0
  O  O25  1  0.750  0.716  0.877  1.0
  O  O26  1  0.750  0.731  0.244  1.0
  O  O27  1  0.250  0.769  0.744  1.0
  O  O28  1  0.250  0.784  0.377  1.0
  O  O29  1  0.750  0.776  0.522  1.0
  O  O30  1  0.750  0.968  0.344  1.0
  O  O31  1  0.250  0.991  0.103  1.0
[/CIF]
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The structure described by Eu2SiO5 crystallizes in the orthorhombic Pnma space group. There are two inequivalent Eu sites. In the first Eu site, Eu(1) is bonded in a 7-coordinate geometry to one O(1), one O(3), one O(4), two equivalent O(2), and two equivalent O(5) atoms. In the second Eu site, Eu(2) is bonded in a 7-coordinate geometry to one O(4), one O(5), two equivalent O(3), and three equivalent O(1) atoms. Si(1) is bonded to one O(2), one O(3), one O(5), and two equivalent O(4) atoms to form distorted corner-sharing SiO5 trigonal bipyramids. There are five inequivalent O sites. In the first O site, O(1) is bonded to one Eu(1) and three equivalent Eu(2) atoms to form OEu4 tetrahedra that share corners with two equivalent O(1)Eu4 tetrahedra, corners with five equivalent O(3)Eu3Si tetrahedra, corners with five equivalent O(5)Eu3Si tetrahedra,  an edgeedge with one O(3)Eu3Si tetrahedra, and edges with two equivalent O(1)Eu4 tetrahedra. In the second O site, O(2) is bonded in a distorted trigonal planar geometry to two equivalent Eu(1) and one Si(1) atom. In the third O site, O(3) is bonded to one Eu(1), two equivalent Eu(2), and one Si(1) atom to form distorted OEu3Si tetrahedra that share  a cornercorner with one O(5)Eu3Si tetrahedra, corners with two equivalent O(3)Eu3Si tetrahedra, corners with five equivalent O(1)Eu4 tetrahedra,  an edgeedge with one O(1)Eu4 tetrahedra, and edges with two equivalent O(5)Eu3Si tetrahedra. In the fourth O site, O(4) is bonded in a 4-coordinate geometry to one Eu(1), one Eu(2), and two equivalent Si(1) atoms. In the fifth O site, O(5) is bonded to one Eu(2), two equivalent Eu(1), and one Si(1) atom to form distorted OEu3Si tetrahedra that share  a cornercorner with one O(3)Eu3Si tetrahedra, corners with two equivalent O(5)Eu3Si tetrahedra, corners with five equivalent O(1)Eu4 tetrahedra, and edges with two equivalent O(3)Eu3Si tetrahedra. is represented by the CIF file [CIF]
data_Eu2SiO5
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   3.746
_cell_length_b   10.654
_cell_length_c   10.980
_cell_angle_alpha   90.000
_cell_angle_beta   90.000
_cell_angle_gamma   90.000
_symmetry_Int_Tables_number   1
_cell_volume   438.252
_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
  Eu  Eu0  1  0.250  0.095  0.289  1.0
  Eu  Eu1  1  0.250  0.135  0.942  1.0
  Eu  Eu2  1  0.750  0.365  0.442  1.0
  Eu  Eu3  1  0.750  0.405  0.789  1.0
  Eu  Eu4  1  0.250  0.595  0.211  1.0
  Eu  Eu5  1  0.250  0.635  0.558  1.0
  Eu  Eu6  1  0.750  0.865  0.058  1.0
  Eu  Eu7  1  0.750  0.905  0.711  1.0
  Si  Si8  1  0.250  0.182  0.626  1.0
  Si  Si9  1  0.750  0.318  0.126  1.0
  Si  Si10  1  0.250  0.682  0.874  1.0
  Si  Si11  1  0.750  0.818  0.374  1.0
  O  O12  1  0.750  0.009  0.897  1.0
  O  O13  1  0.250  0.032  0.656  1.0
  O  O14  1  0.250  0.224  0.478  1.0
  O  O15  1  0.750  0.216  0.623  1.0
  O  O16  1  0.750  0.231  0.256  1.0
  O  O17  1  0.250  0.269  0.756  1.0
  O  O18  1  0.250  0.284  0.123  1.0
  O  O19  1  0.750  0.276  0.978  1.0
  O  O20  1  0.750  0.468  0.156  1.0
  O  O21  1  0.250  0.491  0.397  1.0
  O  O22  1  0.750  0.509  0.603  1.0
  O  O23  1  0.250  0.532  0.844  1.0
  O  O24  1  0.250  0.724  0.022  1.0
  O  O25  1  0.750  0.716  0.877  1.0
  O  O26  1  0.750  0.731  0.244  1.0
  O  O27  1  0.250  0.769  0.744  1.0
  O  O28  1  0.250  0.784  0.377  1.0
  O  O29  1  0.750  0.776  0.522  1.0
  O  O30  1  0.750  0.968  0.344  1.0
  O  O31  1  0.250  0.991  0.103  1.0
[/CIF]
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