Davidsmithite Rossi G, Oberti R, Smith D C European Journal of Mineralogy 1 (1989) 59-70 The crystal structure of a K-poor Ca-rich silicate with the nepheline framework, and crystal-chemical relationships in the compositional space (K,Na,Ca,_)8(Al,Si)16O32 Sample: G201b7 _database_code_amcsd 0006340 9.982 9.982 8.364 90 90 120 P6_3 atom x y z occ Biso B(1,1) B(2,2) B(3,3) B(1,2) B(1,3) B(2,3) Na .9945 .4423 .9902 .98 1.7 .0063 .0050 .0049 .0020 .0003 -.0038 Ca 0 0 .9854 .035 4.7 .0159 .0159 .0162 .0079 0 0 Na 0 0 .9854 .38 4.7 .0159 .0159 .0162 .0079 0 0 K 0 0 .9854 .10 4.7 .0159 .0159 .0162 .0079 0 0 Ca' 0 0 .8358 .25 10.2 .0052 .0052 .0981 .0026 0 0 Na' 0 0 .8358 .01 10.2 .0052 .0052 .0981 .0026 0 0 AlT1 1/3 2/3 .1805 2.0 .0076 .0076 .0057 .0038 0 0 SiT2 1/3 2/3 .7951 0.9 .0028 .0028 .0038 .0015 0 0 SiT3 .0926 .3325 .3028 1.3 .0040 .0004 .0079 .0002 .0022 .0016 AlT4 .0955 .3343 .6768 1.5 .0027 .0107 .0039 .0044 .0015 .0021 O1 .3324 .7128 .9727 1/3 3.9 .0235 .0154 .0038 .0120 -.0003 -.0051 O2 .0298 .3200 .4886 3.8 .0087 .0295 .0057 .0138 -.0006 -.0017 O3 .1755 .5256 .7196 2.9 .0031 .0042 .0233 .0017 -.0007 .0032 O4 .1620 .5067 .2297 3.2 .0069 .0019 .0231 .0011 -.0039 .0002 O5 .2281 .2868 .2990 2.2 .0032 .0069 .0109 .0010 -.0025 -.0030 O6 .2233 .2686 .6825 2.5 .0129 .0151 .0053 .0125 -.0032 -.0042