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 Ni80, CaNi.74Mg.26Si2O6 _database_code_amcsd 0001334 9.7372 8.8986 5.2313 90 105.826 90 C2/c atom x y z occ Biso Ni1 0 .9095 .25 .74 0.37 Mg1 0 .9095 .25 .26 0.37 Ca2 0 .2985 .25 .635 Si .2867 .0938 .2389 .349 O1 .1153 .0860 .1453 0.51 O2 .3590 .2532 .3202 0.65 O3 .3505 .0184 .9901 0.56