29Si MAS NMR spectrum and superstructure of modulated tridymite L3-To(MX-1)
Graetsch, Heribert; Topalovlć-Dierdorf, Ivana
European Journal of Mineralogy Volume 8 Number 1 (1996), p. 103 - 114
published: Feb 22, 1996
manuscript accepted: Sep 15, 1995
manuscript received: Dec 27, 1994
ArtNo. ESP147050801012, Price: 29.00 €
Abstract The 29Si MAS NMR spectrum of the third room-temperature modification of tridymite (L3-To(MX-1)) exhibits ten partly resolved signals, which are assigned to 24 symmetrically independent silicon atoms. The incommensurate superstructure was refined with single-crystal x-ray diffraction data, showing that the modulation consists of a complex system of tilted tetrahedra, which can be described as a combination of transverse and longitudinal wave-like shifts of the atoms without severe distortions of the tetrahedral units themselves.