City Research Online

Abstract

X-ray crystallography and Mdssbauer spectroscopy have been used to study some tin(II) materials. Some alkali metal and ammonium halostannates have been prepared both from aqueous solutions and from solid state melts.

The crystal structures of 3 materials have been determined viz. RbSn2Br5, CsSn3Br1.5F5 and KBr.KSnBr2C1.H2O; and the structures of KC1.KSnC13.H2O and S3BrF5 have been refined. The structure of RbSn2Br5 is stabilised by overlap of the 5s orbital on tin and empty 4d orbitals on the bromine atoms, resulting in partial delocalistion of the non-bonding electron pairs on tin. This is part of a range of interactions shown by the lone pairs on tin atoms ranging from dimer formation to the population of solid state conduction bands.

Preparations in solution and in the solid state have confirmed the existence of mixed halide complexes of tin(II). Evidence from the structure determination of KBr.KSnBr2c1i.H2O suggests two halogen atom sites on the [SnX3]- anion are interchangeable between bromine andchlorine. The expansion of the lattice in accomodating the has larger halide in salts of the type been monitored using X-ray the type KSnBrnC13-n.xH2O has been monitored using X-ray powder diffraction.

Thermal analysis phase diagrams and has been used in the construction of together with X-ray powder diffraction is used to identify new phases in the system KBr:SnX2 where X = Br.Cl.F.

The conversion electron Mössbauer (CEM) spectra for some normal tin(II) compounds are reported and have been compared with transmission Mössbauer data. Some applications of CEMS, in commercially important materials, are discussed and results on several examples are reported, including ceramic tiles and glazes, tinplates and alloys, fabrics, glass coatings and biocides.

Publication Type:	Thesis (Doctoral)
Subjects:	Q Science > QD Chemistry
Departments:	School of Science & Technology School of Science & Technology > School of Science & Technology Doctoral Theses Doctoral Theses

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