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 = 5 K _database_code_amcsd 0007199 7.39675 7.39675 15.8465 90 90 90 *P4/ncc .25 -.25 0 atom x y z occ Uiso Ba .25 .75 0 .5 .0253 Sr .25 .75 0 .5 .0253 Cu .25 .25 .09138 .0459 Si .5123 .9335 .15175 .0257 O1 .4544 .9842 .2459 .5 .0558 O2 .7178 -.0002 .13313 .0555 O3 .3736 .0234 .08813 .0668