Despite the importance of the chloride ion in magmas and the fluids that separate from them, very little is known about atomic-scale structural environments for Cl– in silicate glasses. We present here the first solid-state 35Cl NMR data for Cl in silicate and aluminosilicate glasses, made possible by the availability of very high (14.1 to 18.8 Tesla) magnetic fields. We find that 35Cl has a wide range in chemical shifts that correlate well with cation-Cl distance and thus contain considerable structural information. In general, Cl is coordinated primarily by network-modifying alkali or alkaline earth cations, and we see no evidence for Al-Cl bonding.
Jonathan F. Stebbins* and Lin-Shu Du
Department of Geological and Environmental Sciences, Stanford University, Stanford, California 94305-2115, U.S.A.
Correspondence: * E-mail: stebbins@pangea.stanford.edu
