The compound described by MgEu2Si2O7 crystallizes in the tetragonal P-42_1m space group. Mg(1) is bonded to four equivalent O(2) atoms to form MgO4 tetrahedra that share corners with four equivalent Si(1)O4 tetrahedra. Eu(1) is bonded in a 8-coordinate geometry to one O(1), three equivalent O(3), and four equivalent O(2) atoms. Si(1) is bonded to one O(1), one O(3), and two equivalent O(2) atoms to form SiO4 tetrahedra that share  a cornercorner with one Si(1)O4 tetrahedra and corners with two equivalent Mg(1)O4 tetrahedra. There are three inequivalent O sites. In the first O site, O(1) is bonded in a 4-coordinate geometry to two equivalent Eu(1) and two equivalent Si(1) atoms. In the second O site, O(2) is bonded in a 4-coordinate geometry to one Mg(1), two equivalent Eu(1), and one Si(1) atom. In the third O site, O(3) is bonded in a 4-coordinate geometry to three equivalent Eu(1) and one Si(1) atom. is represented by the CIF file [CIF]
data_Eu2MgSi2O7
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   8.064
_cell_length_b   8.064
_cell_length_c   5.218
_cell_angle_alpha   90.000
_cell_angle_beta   90.000
_cell_angle_gamma   90.000
_symmetry_Int_Tables_number   1
_cell_volume   339.339
_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
  Eu  Eu0  1  0.335  0.835  0.491  1.0
  Eu  Eu1  1  0.665  0.165  0.491  1.0
  Eu  Eu2  1  0.165  0.335  0.509  1.0
  Eu  Eu3  1  0.835  0.665  0.509  1.0
  Mg  Mg4  1  0.000  0.000  0.000  1.0
  Mg  Mg5  1  0.500  0.500  0.000  1.0
  Si  Si6  1  0.139  0.639  0.058  1.0
  Si  Si7  1  0.861  0.361  0.058  1.0
  Si  Si8  1  0.361  0.139  0.942  1.0
  Si  Si9  1  0.639  0.861  0.942  1.0
  O  O10  1  0.000  0.500  0.165  1.0
  O  O11  1  0.079  0.811  0.202  1.0
  O  O12  1  0.311  0.579  0.202  1.0
  O  O13  1  0.689  0.421  0.202  1.0
  O  O14  1  0.921  0.189  0.202  1.0
  O  O15  1  0.358  0.142  0.252  1.0
  O  O16  1  0.642  0.858  0.252  1.0
  O  O17  1  0.142  0.642  0.748  1.0
  O  O18  1  0.858  0.358  0.748  1.0
  O  O19  1  0.189  0.079  0.798  1.0
  O  O20  1  0.421  0.311  0.798  1.0
  O  O21  1  0.579  0.689  0.798  1.0
  O  O22  1  0.811  0.921  0.798  1.0
  O  O23  1  0.500  0.000  0.835  1.0
[/CIF]
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The compound described by MgEu2Si2O7 crystallizes in the tetragonal P-42_1m space group. Mg(1) is bonded to four equivalent O(2) atoms to form MgO4 tetrahedra that share corners with four equivalent Si(1)O4 tetrahedra. Eu(1) is bonded in a 8-coordinate geometry to one O(1), three equivalent O(3), and four equivalent O(2) atoms. Si(1) is bonded to one O(1), one O(3), and two equivalent O(2) atoms to form SiO4 tetrahedra that share  a cornercorner with one Si(1)O4 tetrahedra and corners with two equivalent Mg(1)O4 tetrahedra. There are three inequivalent O sites. In the first O site, O(1) is bonded in a 4-coordinate geometry to two equivalent Eu(1) and two equivalent Si(1) atoms. In the second O site, O(2) is bonded in a 4-coordinate geometry to one Mg(1), two equivalent Eu(1), and one Si(1) atom. In the third O site, O(3) is bonded in a 4-coordinate geometry to three equivalent Eu(1) and one Si(1) atom. is represented by the CIF file [CIF]
data_Eu2MgSi2O7
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   8.064
_cell_length_b   8.064
_cell_length_c   5.218
_cell_angle_alpha   90.000
_cell_angle_beta   90.000
_cell_angle_gamma   90.000
_symmetry_Int_Tables_number   1
_cell_volume   339.339
_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
  Eu  Eu0  1  0.335  0.835  0.491  1.0
  Eu  Eu1  1  0.665  0.165  0.491  1.0
  Eu  Eu2  1  0.165  0.335  0.509  1.0
  Eu  Eu3  1  0.835  0.665  0.509  1.0
  Mg  Mg4  1  0.000  0.000  0.000  1.0
  Mg  Mg5  1  0.500  0.500  0.000  1.0
  Si  Si6  1  0.139  0.639  0.058  1.0
  Si  Si7  1  0.861  0.361  0.058  1.0
  Si  Si8  1  0.361  0.139  0.942  1.0
  Si  Si9  1  0.639  0.861  0.942  1.0
  O  O10  1  0.000  0.500  0.165  1.0
  O  O11  1  0.079  0.811  0.202  1.0
  O  O12  1  0.311  0.579  0.202  1.0
  O  O13  1  0.689  0.421  0.202  1.0
  O  O14  1  0.921  0.189  0.202  1.0
  O  O15  1  0.358  0.142  0.252  1.0
  O  O16  1  0.642  0.858  0.252  1.0
  O  O17  1  0.142  0.642  0.748  1.0
  O  O18  1  0.858  0.358  0.748  1.0
  O  O19  1  0.189  0.079  0.798  1.0
  O  O20  1  0.421  0.311  0.798  1.0
  O  O21  1  0.579  0.689  0.798  1.0
  O  O22  1  0.811  0.921  0.798  1.0
  O  O23  1  0.500  0.000  0.835  1.0
[/CIF]
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