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 Rich59 Atomic parameters from ICSD _database_code_amcsd 0001610 10.0613 18.0314 5.2963 90 104.896 90 C2/m atom x y z occ Biso O1 .1134 .0887 .2197 .8 O2 .1164 .172 .724 .8 OH .1072 0 .7188 .8 .8 F .1072 0 .7188 .2 .8 O4 .3562 .248 .7931 .8 O5 .3357 .1288 .0945 1.1 O6 .3387 .1152 .5893 1.1 O7 .3296 0 .3115 1.2 Si1 .2766 .0853 .3035 .4 Si2 .2843 .1712 .8103 .86 .4 Ti .2843 .1712 .8103 .14 .4 Mg1 0 .0891 .5 .6 Mg2 0 .1789 0 .6 Mg3 0 0 0 .6 Na 0 .2768 .5 .5 .9 Ca 0 .2768 .5 .5 .9 K .0198 .5 .0538 .5 2.3