data_global
_chemical_name_mineral 'Gugiaite'
loop_
_publ_author_name
'Yang Z'
'Fleck M'
'Pertlik F'
'Tillmanns E'
'Tao K'
_journal_name_full 'Neues Jahrbuch fur Mineralogie, Monatshefte'
_journal_volume 2001 
_journal_year 2001
_journal_page_first 186
_journal_page_last 192
_publ_section_title
;
 The crystal structure of natural gugiaite, Ca2BeSi2O7
 Note, z coordinate of Ca is altered to reproduce reported Ca-O bond lengths
;
_database_code_amcsd 0014911
_chemical_compound_source 'skarn rocks in the Gugia alkaline complex, Liaoning Province, China'
_chemical_formula_sum 'Ca2 Be Si2 O7'
_cell_length_a 7.4330
_cell_length_b 7.4330
_cell_length_c 4.9970
_cell_angle_alpha 90
_cell_angle_beta 90
_cell_angle_gamma 90
_cell_volume 276.082
_exptl_crystal_density_diffrn      3.096
_symmetry_space_group_name_H-M 'P -4 21 m'
loop_
_space_group_symop_operation_xyz
  'x,y,z'
  '1/2-y,1/2-x,z'
  'y,-x,-z'
  '1/2-x,1/2+y,-z'
  '-x,-y,z'
  '1/2+y,1/2+x,z'
  '-y,x,-z'
  '1/2+x,1/2-y,-z'
loop_
_atom_site_label
_atom_site_fract_x
_atom_site_fract_y
_atom_site_fract_z
_atom_site_U_iso_or_equiv
Ca   0.16376   0.66376  -0.48894   0.01770
Be   0.00000   0.00000   0.00000   0.00380
Si   0.35325   0.85325  -0.03960   0.01380
O1   0.50000   0.00000   0.83590   0.01720
O2   0.35940   0.85940   0.27860   0.01620
O3   0.33320   0.41440   0.18160   0.01740
loop_
_atom_site_aniso_label
_atom_site_aniso_U_11
_atom_site_aniso_U_22
_atom_site_aniso_U_33
_atom_site_aniso_U_12
_atom_site_aniso_U_13
_atom_site_aniso_U_23
Ca 0.01860 0.01860 0.01610 -0.00390 -0.00070 -0.00070
Be 0.00470 0.00470 0.00200 0.00000 0.00000 0.00000
Si 0.01340 0.01340 0.01450 -0.00040 -0.00030 -0.00030
O1 0.01720 0.01720 0.01700 -0.00180 0.00000 0.00000
O2 0.01640 0.01640 0.01580 -0.00060 -0.00010 -0.00010
O3 0.01350 0.02220 0.01640 -0.00260 -0.00040 0.00260