Richterite Della Ventura G, Robert J-L, Beny J-M, Raudsepp M, Hawthorne F C American Mineralogist 78 (1993) 980-987 The OH-F substitution in Ti-rich potassium richterite: Rietveld structure refinement and FTIR and micro-Raman spectroscopic studies of synthetic amphiboles in the system K2O-Na2O-CaO-MgO-SiO2-TiO2-H2O-HF Sample Rich58 Atomic parameters from ICSD _database_code_amcsd 0001609 10.0746 18.0337 5.2979 90 104.906 90 C2/m atom x y z occ Biso O1 .1113 .0878 .2141 .8 O2 .1163 .1713 .7245 .8 O3 .1063 0 .7174 .8 O4 .3548 .2474 .7939 .8 O5 .3398 .1293 .098 1.1 O6 .3363 .1162 .5859 1.1 OH .3304 0 .3071 1.2 Si1 .283 .085 .3023 .4 Si2 .283 .1708 .8091 .85 .4 Ti .283 .1708 .8091 .15 .4 Mg1 0 .0897 .5 .6 Mg2 0 .1797 0 .6 Mg3 0 0 0 .6 Na 0 .277 .5 .5 .9 Ca 0 .277 .5 .5 .9 K .0179 .5 .0427 .5 2.3