Structure of the zeolite theta-1. Redetermination using single-crystal synchrotron-radiation data

Abstract

Single-crystal synchrotron-radiation data have been recorded, using an area detector, for a crystal of dimensions 4 x 8 x 125 p,m, composition SiO2, and the structure redetermined. R = 0.116 for 394 reflections with F > 6tr(F). The unit cell, and the framework of SiO4 tetrahedra, sharing corners, with channels parallel to e, previously established from powder diffraction data by Highcock, Smith & Wood [Acta Cryst. (1985), C41, 1391-1394] is confirmed, but atom positions (z parameters) are revised by 0.1-2A. M,=60.1, Cmc2~, a= 13.836(3), b= 17.41.'(4), c=5.042(1)A, V=1215A 3, Z=24, a= 0.914 A_