0277-5387/00/$ - see front matter q2000 Elsevier Science Ltd All rights reserved. PII S0277-5387 ( 99 ) 00359-9 Friday Feb 25 09:49 AM StyleTag -- Journal: POLY (Polyhedron) Article: 3310 www.elsevier.nl/locate/poly Polyhedron 19 (2000) 297–305 Time-resolved, in situ X-ray diffraction studies of intercalation in lamellar hosts Dermot O’Hare *, John S.O. Evans 1 , Andrew Fogg, Stephen O’Brien Inorganic Chemistry Laboratory, South Parks Road, Oxford OX1 3QR, UK Received 25 April 1999; accepted 29 August 1999 Abstract Energy dispersive X-ray diffraction (EDXRD) has been used to perform in situ kinetic studies on the intercalation of a range of guest molecules in layered lattices. The kinetics of the intercalation of cations (K q , PyH q (PysC 5 H 5 N), NMe 4 q ) and the long chain ammonium ions C 12 TMA, C 16 TMA, C 18 TMA (C 12 TMAsdodecyltrimethylammonium, C 16 TMAshexadecyltrimethylammonium and C 18 TMAsoctadecyltrimethylammonium) into crystals of MnPS 3 have been determined. These reactions are very fast, and in some cases novel transient phases are observed. The rate of cobaltocene, Co(h-C 5 H 5 ) 2 , intercalation in layered metal dichalcogenides ZrS 2 , 2H-SnS 2 , 2H-SnSe 2 , 2H-TaS 2 , 2H-NbS 2 , 1T-TaS 2 and TiS 2 has also been investigated. Integrated intensities of the Bragg reflections have been used to determine the extent of reaction (a) versus time for each of these reactions. A number of kinetic models have been considered, including the Avrami–Erofeyev (ms1.5) deceleratory nuclei-growth model and statistical simulation. The concentration and solvent dependence of the rate of Co(h-C 5 H 5 ) 2 intercalation into 2H-SnS 2 has also been determined. Surprisingly, we find that the rate of intercalation is invariant to the initial Co(h-C 5 H 5 ) 2 concentration over a wide concentration range. The rate of intercalation of the lithium salts (LiX; XsCl, Br, NO 3 and OH) into Gibbsite (g-Al(OH) 3 ) giving the layered double hydroxides [LiAl 2 (OH) 6 ]XPnH 2 O (XsCl, Br, NO 3 and OH) and [LiAl 2 (OH) 6 ] 2 SO 4 PnH 2 O has been studied. The temperature dependence of the rate of intercalation of LiCl yields an activation energy of 27 kJ mol y1 . The reaction was also found to be half order with respect to the initial concentration of LiCl. Time-resolved in situ energy dispersive X-ray powder diffraction (EDXRD) spectra have been recorded following the addition of an aqueous solution of hexadecyltri- methylammonium chloride (C 16 H 33 N q Me 3 Cl y sC 16 TMACl) to kanemite (NaHSi 2 O 5 P3H 2 O). The diffraction data suggest that initially a layered phase forms due to intercalation of the alkylammonium ions which then transforms into a silicate-organic mesophase which is the precursor to the hexagonal mesoporous silicate, FSM-16. q2000 Elsevier Science Ltd All rights reserved. Keywords: In situ X-ray diffraction; Intercalation; Layered compounds; Solid state; Synchrotron radiation 1. Introduction Some of the earliest and most extensive studies of the kinetics of intercalation reactions were carried out using graphite crystals. For example, classic experiments per- formed by Hooley and co-workers investigated the gain in weight of a graphite flake under a bromine atmosphere [1,2]. Until recently, only two time-resolved diffraction studies on metal chalcogenide intercalation have been reported [3–7]. The study by Riekel and Schollhorn measured time-resolved neutron diffraction data during the intercalation of 2H-TaS 2 with NH 3 (g). However, the available levels of beam flux, whilst high by neutron standards, necessitated either very large sample sizes (;15 g) or long acquisition times, making * Corresponding author; e-mail: dermot.ohare@chem.ox.ac.uk 1 Present address: Department of Chemistry, Durham University, Durham DH1 3LE, UK. a thorough, quantitative study under varying reaction condi- tions of temperature, concentration and particle size unfeas- ible. Moreover, because of the large incoherent scattering from hydrogen atoms by neutrons, the samples studied had to be highly deuterated, an expensive and not always achiev- able prerequisite for other intercalation reactions. Even taking all these previous experiments into consideration, we still have a fairly rudimentary understanding of the intimate mech- anism of intercalation reactions. Knowledge of the critical factors which control the rates of these reactions is based on a limited range of experiments. We still commonly use the schematic illustration shown in Fig. 1 to describe these reac- tions, which undoubtedly greatly oversimplifies the true picture. In recent years, the technological and experimental advances in energy dispersive powder diffraction (EDXRD) using synchrotron X-ray sources have provided new possi-