Vlasovite Voronkov A A, Zhdanova T A, Pyatenko Y A Kristallografiya 19 (1974) 252-259 Refinement of the structure of vlasovite Na2ZrSi4O11 and some characteristics of the composition and structure of the zirconosilicates _database_code_amcsd 0014182 10.98 10.00 8.52 90 100.40 90 C2/c atom x y z Biso Na1 0 .075 .75 3.4 Na2 0 .395 .75 5.1 Zr .25 .25 0 1.9 Si1 .2637 .0722 .6385 1.4 Si2 .0498 .2178 .4272 1.4 O1 0 .160 .25 2.2 O2 .143 .106 .505 2.7 O3 .115 .358 .419 3.1 O4 .056 .230 .971 1.9 O5 .242 .134 .801 2.3 O6 .287 .084 .145 2.3