Cristobalite Gibbs G V, Boisen M B, Downs R T, Lasaga A C Materials Research Society Symposia Proceedings 121 (1988) 155-165 Mathematical Modeling of the structures and bulk moduli of TX2 quartz and cristobalite structure types, T = C, Si, Ge and X = O, S Locality: theoretical _database_code_amcsd 0018754 4.973 4.973 6.627 90 90 90 P4_12_12 atom x y z Si .312 .312 0 O .234 .123 .192