data_global
_chemical_name_mineral 'Melilite'
loop_
_publ_author_name
'Bindi L'
'Bonazzi P'
_journal_name_full 'Physics and Chemistry of Minerals'
_journal_volume 32 
_journal_year 2005
_journal_page_first 89
_journal_page_last 96
_publ_section_title
;
 Incommensurate-normal phase transition in natural melilite:
 an in situ high-temperature X-ray single-crystal study
 Sample: San Venanzo, Italy; T = 413 K
 Note: xO1 and yO1 corrected by authors
;
_database_code_amcsd 0008957
_chemical_formula_sum 'Ca1.87 Na.1 Sr.02 K.02 Mg.96 Al.09 Si1.98 O7'
_cell_length_a 7.838
_cell_length_b 7.838
_cell_length_c 5.006
_cell_angle_alpha 90
_cell_angle_beta 90
_cell_angle_gamma 90
_cell_volume 307.540
_exptl_crystal_density_diffrn      2.950
_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_occupancy
_atom_site_U_iso_or_equiv
CaX   0.33190   0.16810   0.50570   0.93500   0.03720
NaX   0.33190   0.16810   0.50570   0.05000   0.03720
SrX   0.33190   0.16810   0.50570   0.01000   0.03720
KX   0.33190   0.16810   0.50570   0.01000   0.03720
MgT1   0.00000   0.00000   0.00000   0.96000   0.02930
AlT1   0.00000   0.00000   0.00000   0.07000   0.02930
SiT2   0.14010   0.35990   0.93470   0.99000   0.02770
AlT2   0.14010   0.35990   0.93470   0.01000   0.02770
O1   0.50000   0.00000   0.18130   1.00000   0.03870
O2   0.14110   0.35890   0.25420   1.00000   0.04120
O3   0.08040   0.18730   0.78620   1.00000   0.03800