Effenbergerite Knight K S, Henderson C M B European Journal of Mineralogy 19 (2007) 189-200 Structural basis for the anomalous low-temperature thermal expansion behavior of the gillespite-structured phase Ba0.5Sr0.5CuSi4O10 Sample: T = 250 K _database_code_amcsd 0007205 7.39428 7.39428 15.8573 90 90 90 *P4/ncc .25 -.25 0 atom x y z occ Uiso Ba .25 .75 0 .5 .0704 Sr .25 .75 0 .5 .0704 Cu .25 .25 .0921 .0838 Si .5126 .9338 .15210 .0389 O1 .4527 .9870 .2458 .5 .1116 O2 .7186 -.0002 .13377 .0893 O3 .3747 .0245 .08834 .0930