Intercalates cationic

Clay materials show a different behavior. They are either cation-poor or cation-rich sheet silicates. They can swell by taking up varying amounts of water between the sheets. If the intercalated cations are hydrated as in montmorillonite, they act as cation exchangers. Montmorillonite, especially when it has intercalated Ca2+ ions, has thixotropic properties and is used to seal up drill holes. The effect is due to the charge distribution on... 

The use of thin-film cathodes for battery application usually results in a better performance due to shorter diffusion path of intercalated cation through solid matrix. The thin film electrodes are used in manufacturing of rolled type batteries and thin film cells. 

The intercalated cationic radical initiator was synthesized from 2,2 -azobis[2-methyl-N-(2-hydroxyethyl) propionamide] by esterification with bromoacetyl bromide, and subsequent quaternization with tributylamine. Sodium montmorillonite was suspended in deionized water. The cationic radical initiator was bound onto the montmorillonite by ion exchange. 

Synthesis and characterization of mesostructured molybdenum sulfides with intercalated cationic surfactants... 

Kapuscinski, J. and Darzynkiewicz, Z. (1984) Condensation of nucleic acids by intercalating cations. Proc. Natl. Acad. Sci. USA, 81,7368-7372. 

The electrochemical reduction of Ti02 is known to be accompanied by the intercalation of small cations. This finding has been explored in sensitizing anatase films for battery applications [149]. Cation coordination to titanium alkoxide sol-gel precursors is also well known [150]. Lyon and Hupp used quartz crystal microbalance techniques to determine the mass of intercalating cations as the TiOa film is reduced [151]. Hagfeldt and co-workers have studied Li+ and Na intercalation into anatase Ti02 both theoretically and experimentally [152, 153). They found that the diffusion constants for Li and Na+ are temperature dependent with an activation barrier of 0.4 eV for insertion and 0.5 eV for extraction. The Li+ diffusion coefficient at 25 °C into the nanoporous structure was approximately 2 X 10 cm s for insertion and 4 x 10 cm s for extraction. 

The size and number of intercalated cations have a pronounced effect on the electronic structure of has a low-lying acceptor orbital... 

Various structural arrangements are associated with the A intercalated cations ( 16.4.3.2.). Electronic transfer, often not considered significant, plays an essential role in the formation of intercalation compounds and the occurrence of phase transitions in a given system. Even the so-called Ac parameter expansion, perpendicular to the slabs of a layered host structure, has an electronic component. 

The sulfonate derivatives (Fig. 4A), in which introduction of suitable ligand functions takes place at the para-position of the aromatic ring, are the most widely studied of the w ater-soluble calixarenes. Their solid-state binding to a wide range of metallic cations and complexes was reviewed by Raston and Atwood. The ability of these molecules to intercalate cations in expandable layers between bilayers of para-sulfonato-calix[4]arene led Atwood and Coleman in 1988 to name these systems Organic Clays." (Fig. 4C). Since then. Atwood extended the structural types observed to include liposomal analogues, tubes, and various Archimedian and Platonic solids."... 

WO3 is an example of another class of electroactive material, metal oxides, which has been used to construct microelectrochemical devices. WO3 is a wide-band-gap semiconductor, with high resistance in its neutral state.Upon reduction, WO3 intercalates cations such as H" ", Li" ", and Na and becomes conducting. W03 based transistors, showing sensitivity to pH and to Li" concentration have been demonstrated in solution electrolytes. A schematic of a MEEP/WO3 device is shown in Figure 3. WO3 is confined to the required electrodes, using standard photolithographic techniques. 

The first most significant papers in the literature, which investigated the potential of layered silicates as possible host lattices of active catalysts for the synthesis of polyolefin nanocomposites, were reported by O Hare, Mulhaupt, and Garces. O Hare et al. used ion exchange to intercalate cationic metallocene species into clay interlayer galleries, followed... 

A new class of solid acid-base catalysts is developed from mineral clays [183]. They have a two-dimensional layer lattice in which oxyanions are exchanged by hydrated cations. These intercalated cations with acid properties give the so-called pillared clays [188] having structural cavities - whose sizes can be controlled - similarly to those in zeolites. Both three and two-dimensional solid acid catalysts are very useful for selecting reactants and products of catalytic processes, among them some isomers of profound petrochemical significance [189]. 

From the X-ray diffraction data, the basal spacings of [B] and [D] were estimated to be 13.6 A in both cases, which can be interpreted as the sum of the van der Waals interval occupied by alkyl chains, 4.0 A, and of that of the silicate layer, 9.6 A, respectively. It shows that the intercalated cations are oriented with the flat-lying monolayer structure in the interlamellar space of the silicate. The interlayer surface area of an unit cell can be calculated as ax b = 5. 14 Ax9.00 A = 46.3 A for montmorillonite and 5.28 Ax9.18 A = 48.5 A for saponite respectively. Since the effective surface area of one -hexylammonium ion is 45.16 A [11], the silicate surface is covered by n-hexylammonium cations up to about 69% in the montmorillonite and to 75% in the saponite. 

Ti02 has an open crystal structure and the Ti ion has a variable electronic structure. As a result, 1102 can accept electrons from different ions and provide empty sites for intercalated cations such as Li+, H+, and Na+. To maintain charge neutrality, electrons will accompany cations such as LP ions into the Ti02 lattice. Lithium intercalation into and deintercalation from Ti02 can be expressed as Equation 8.3, and the reversibility of this reaction is related to its cycling performance ... 

The stmctural modification with respect to the pristine compound results in changes of the unit cell parameters of the pristine material that are related to the radii of the guest ions, the size of the empty sites of the host lattice and the nature of these sites, i.e., octahedron or tetrahedron. It has been shown that intercalation of alkali ions can induce staging phenomenon due to the minimization of repulsive forces between intercalated cations and a special ordering that results in superstrac-tures [13, 14]. 

---