Diopside Raudsepp M, Hawthorne F C, Turnock A C American Mineralogist 75 (1990) 1274-1281 Crystal chemistry of synthetic pyroxenes on the join CaNiSi2O6-CaMgSi2O6 (diopside): A Rietveld refinement study sample Ni50, CaNi.45Mg.55Si2O6 _database_code_amcsd 0001335 9.7390 8.9094 5.2375 90 105.848 90 C2/c atom x y z occ Biso Ni1 0 .9079 .25 .45 0.37 Mg1 0 .9079 .25 .55 0.37 Ca2 0 .2994 .25 .635 Si .2865 .0934 .2283 .349 O1 .1150 .0874 .1439 0.51 O2 .3610 .2519 .3190 0.65 O3 .3514 .0178 .9961 0.56