Layered metal phosphates characterization

Among the inorganic open-framework compounds, the family of phosphates is a large one [3]. A large variety of open-framework metal phosphates of different architectures have been synthesized in the last few years. They include one-dimensional (ID) linear chain and ladder structures, two-dimensional (2D) layer structures and three-dimensional (3D) channel structures [4]. In the linear chain and ladder structures, four-membered metal phosphate units of the type M2P2O4 share comers and edges respectively. Zero-dimensional four-membered zinc phosphates have been synthesised and characterized recently [5]. Several open-framework metal carboxylates have also been reported [6] and the presence of a hierarchy of zinc oxalates covering the monomer, dimer, chain, honeycomb-layer and 3D structures has indeed been established [7]. 

In order to study the formation of interfacial metal phosphate layers, the untreated bare CRS panels were mechanically polished to a mirror finish and used as coating substrates. The ISPC was applied on mirror-finished CRS and cured at 163°C for 15 min. The polymer layer on each panel was removed without damaging the interface by soaking the panel in tetrahydrofuran solvent. The interfacial metal phosphate layer was rinsed with deionized water, dried, and characterized by a Bruker Fourier transform infrared (FTIR) spectrophotometer model Vector 22 equipped with a Spectra Tech FT-80 grazing angle accessory. 

Layered titanium phosphates have many potentially important applications in ion exchange, catalysis, intercalation, and sorption. Characterization of metal local environments by solid-state " /" Ti NMR has been difficult. In this work, the local structures around Ti in several representative layered systems, including alpha-, beta-, and gamma-TiP have been characterized, by examining the static NMR spectra of these ma-... 

Uraniferous black shales are of marine origin and, in addition to colour, are characterized by high sapropelic organic content, abundant pyrite or marcasite in thin lenses, nodules or disseminated particles, and the paucity of calcium and magnesium carbonates. The shales also contain small quantities of such other metals as Mn, Ti, V, Cu, Cr, Mo, P and REE. Most of these metals are dispersed in the shale, but phosphate may also occur as nodules or phosphate-rich layers. ... 

Tetravalent metal phosphonates, or MELS (for Molecularly Engineered Layered Structures), provide a novel class of materials that combine many of the properties of incn-ganic metal oxides with the organic functionality more commonly found in functionalized polymeric resins. Early development work on these materials was carried out by Alberti and co-woikers [ref. 1] and Dines et al. [ref. 2]. Synthesis and characterization of related zirconium phosphates that also contain phosphonate groups as pillars have been described by Clearfield [ref 3]. There is a substantial patent estate for tetravalent metal phosphonates, and exclusive rights to this estate are owned by Catalytica [ref 4]. 

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