data_global _chemical_name_mineral 'K2Ni(H2P2O7)2*2H2O' loop_ _publ_author_name 'Tahiri A A' 'Messouri I' 'Lachkar M' 'Zavalij P Y' 'Glaum R' 'El Bali B' 'Rachid O' _journal_name_full 'Acta Crystallographica, Section E' _journal_volume 60 _journal_year 2004 _journal_page_first i3 _journal_page_last i5 _publ_section_title ; Dipotassium nickel(II) bis(dihydrogendiphosphate) dihydrate, K2Ni(H2P2O7)2*2H2O ; _chemical_formula_sum 'K2 Ni P4 O16 H8' _cell_length_a 6.8554 _cell_length_b 7.3124 _cell_length_c 7.5610 _cell_angle_alpha 81.012 _cell_angle_beta 72.301 _cell_angle_gamma 83.691 _cell_volume 355.869 _exptl_crystal_density_diffrn 2.449 _symmetry_space_group_name_H-M 'P -1' loop_ _symmetry_equiv_pos_as_xyz 'x,y,z' '-x,-y,-z' loop_ _atom_site_label _atom_site_fract_x _atom_site_fract_y _atom_site_fract_z _atom_site_U_iso_or_equiv K 0.89190 0.26756 0.70308 0.03430 Ni 0.50000 0.50000 0.50000 0.01710 P1 0.32676 0.27260 0.24671 0.01770 P2 0.75328 0.19077 0.24060 0.01720 O1 0.56690 0.23100 0.15000 0.02340 O2 0.29830 0.39200 0.39730 0.02070 O3 0.24240 0.35280 0.08860 0.02300 O4 0.23710 0.08130 0.33330 0.02560 H4 0.24800 0.05400 0.43500 0.03700 O5 0.74350 0.33190 0.36810 0.02290 O6 0.93400 0.21450 0.05970 0.02390 H6 1.02100 0.27000 0.06800 0.04800 O7 0.74720 -0.00670 0.33290 0.02630 O1W 0.54890 0.70520 0.27270 0.02370 H1W 0.60800 0.67400 0.17400 0.03600 H2W 0.59600 0.79200 0.28600 0.03600 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 K 0.04140 0.03120 0.03350 0.00840 -0.01850 -0.00600 Ni 0.01830 0.01660 0.01710 -0.00040 -0.00590 -0.00350 P1 0.01700 0.01940 0.01830 -0.00100 -0.00730 -0.00340 P2 0.01690 0.01860 0.01610 0.00000 -0.00500 -0.00310 O1 0.01810 0.03360 0.02100 0.00280 -0.00870 -0.00800 O2 0.01720 0.02260 0.02240 -0.00140 -0.00470 -0.00520 O3 0.02420 0.02700 0.01910 -0.00520 -0.00920 0.00170 O4 0.03550 0.01920 0.02430 -0.00700 -0.01190 0.00070 O5 0.02100 0.02770 0.02270 0.00380 -0.00830 -0.01150 O6 0.02140 0.03130 0.01890 -0.00620 -0.00300 -0.00560 O7 0.03590 0.02020 0.02380 -0.00730 -0.01180 0.00400 O1W 0.03120 0.01970 0.01840 -0.00380 -0.00360 -0.00320