data_global
_chemical_name_mineral 'Melilite'
loop_
_publ_author_name
'Armbruster T'
'Rothlisberger F'
'Seifert F'
_journal_name_full 'American Mineralogist'
_journal_volume 75 
_journal_year 1990
_journal_page_first 847
_journal_page_last 858
_publ_section_title
;
 Layer topology, stacking variation and site distortion in melilite-related
 compounds in the system CaO-ZnO-GeO2-SiO2
 low-temperature polymorph
 Ca2ZnGe1.25Si.75O7
;
_database_code_amcsd 0001316
_chemical_formula_sum 'Zn (Ge1.255 Si.745) Ca2 O7'
_cell_length_a 9.112
_cell_length_b 7.900
_cell_length_c 9.380
_cell_angle_alpha 90
_cell_angle_beta 114.03
_cell_angle_gamma 90
_cell_volume 616.698
_exptl_crystal_density_diffrn      3.981
_symmetry_space_group_name_H-M 'P 1 21/n 1'
loop_
_space_group_symop_operation_xyz
  'x,y,z'
  '1/2+x,1/2-y,1/2+z'
  '1/2-x,1/2+y,1/2-z'
  '-x,-y,-z'
loop_
_atom_site_label
_atom_site_fract_x
_atom_site_fract_y
_atom_site_fract_z
_atom_site_occupancy
Zn1   0.82867   0.09678   0.11477   1.00000
Ge2   0.87207   0.45559   0.20899   0.73400
Si2   0.87207   0.45559   0.20899   0.26600
Ge3   0.96891   0.76878   0.07667   0.52100
Si3   0.96891   0.76878   0.07667   0.47900
Ca4   0.45740   0.28210   0.02820   1.00000
Ca5   0.28910   0.56540   0.20140   1.00000
O1   0.00940   0.56820   0.15720   1.00000
O2   0.63210   0.06250   0.13430   1.00000
O3   0.69150   0.45570   0.05010   1.00000
O4   0.96720  -0.09870   0.21910   1.00000
O5   0.85640   0.18100  -0.06510   1.00000
O6   0.95450   0.26250   0.27640   1.00000
O7   0.29590   0.72920   0.42070   1.00000
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
Zn1 0.00810 0.01010 0.01000 0.00010 0.00440 0.00100
Ge2 0.00610 0.00610 0.00610 0.00000 0.00250 0.00000
Si2 0.00610 0.00610 0.00610 0.00000 0.00250 0.00000
Ge3 0.00590 0.00590 0.00590 0.00000 0.00240 0.00000
Si3 0.00590 0.00590 0.00590 0.00000 0.00240 0.00000
Ca4 0.00870 0.01070 0.00710 0.00240 0.00260 0.00060
Ca5 0.01200 0.02440 0.00920 0.01000 0.00430 0.00140
O1 0.01020 0.01150 0.01370 0.00090 0.00530 0.00240
O2 0.01040 0.01790 0.01420 0.00300 0.00710 0.00810
O3 0.00860 0.01120 0.00840 -0.00010 0.00330 0.00050
O4 0.01160 0.00850 0.00770 0.00160 0.00350 0.00010
O5 0.01200 0.01640 0.01030 0.00140 0.00550 0.00440
O6 0.01450 0.01170 0.00730 -0.00230 0.00090 -0.00050
O7 0.01220 0.01860 0.01340 -0.00100 0.00470 -0.00390