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 = 100 K _database_code_amcsd 0007202 7.39533 7.39533 15.8482 90 90 90 *P4/ncc .25 -.25 0 atom x y z occ Uiso Ba .25 .75 0 .5 .0378 Sr .25 .75 0 .5 .0378 Cu .25 .25 .09160 .0570 Si .5123 .9336 .15183 .0286 O1 .4539 .9849 .2459 .5 .0661 O2 .7179 .0000 .13326 .0641 O3 .3738 .0236 .08818 .0720