Quartz Levien L, Prewitt C T, Weidner D J American Mineralogist 65 (1980) 920-930 Structure and elastic properties of quartz at pressure P = 61.4 kbar _database_code_amcsd 0000794 4.702 4.702 5.256 90 90 120 *P3_221 0 0 .666666667 atom x y z B(1,1) B(2,2) B(3,3) B(1,2) B(1,3) B(2,3) Si .4526 0 0 0.0084 0.0069 0.0039 0.0035 -0.0002 -0.0004 O .4034 .2952 .0987 0.0148 0.0121 0.0064 0.0080 -0.0027 -0.0026