Chemical Thermodynamics of Tin - Volume 12 - OECD Nuclear ...

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A Discussion of selected references
disproportionation at different temperatures, the reaction rate law and the reaction rate
coefficients k and activation energy E A for the disproportionation of SnO and Sn 2 O 3
were extracted. The reaction follows a nucleation and growth mechanism according to
Avrami-Erofeyev with a reaction exponent m = 2. At low temperatures, a synchrotron
radiation-induced disproportionation of SnO was observed.
[2008SEK/TOG]
The structures and stabilities of a series of nonstoichiometric SnO 2−x compounds, which
are yet unknown experimentally, are predicted using the cluster expansion technique
combined with first-principles calculations. A homologous series of Sn n+1 O 2n in which
oxygen vacancies are layered on (101) planes of the rutile lattice is discovered. The
homologous crystals are composed of divalent and quadrivalent Sn atoms. No trivalent
Sn atoms are formed.
[2009GAJ/SIP]
UV spectroscopy has been applied to determine the stability of tin(IV)-chlorido
complexes.
In chloride containing media the stock solution of tin(IV) (≈ 0.1 M) was
prepared by dissolving a known amount of SnCl 4 . 5H 2 O in the given background
electrolyte (x M HClO 4 + 1 M HCl, x = 3 - 7), and its concentration was determined by
ICP-AES. Sn(II) solutions (≈ 0.03 M) were prepared by Tobias’ method [1958TOB]
using 0.03 M CuCl 2 dissolved in the given background electrolyte (x M HClO 4 + 1 M
HCl, x = 3-7). The accurate Sn(II)-concentration of the solution was determined
iodometrically, immediately after preparation. The total tin content of the solutions were
determined by ICP-AES, and were practically identical with the initial CuCl 2
concentrations, determined by complexometry.
The densities of perchloric acid solutions were taken from the literature
[1989LOB]. Those of the mixed electrolytes were determined experimentally, and were
found to be close to those derived from the simple mixture rule Δ
mix
V = 0 , when
aqueous solutions containing different electrolytes of the same ionic strength on
concentration basis are mixed [1987HUM].
The stepwise formation constants of tin(IV)-chlorido complexes were
determined by following the spectral changes, between 200 and 260 nm, of tin(IV)
perchlorate solution upon addition of H(Cl,ClO 4 ) solution, using a Unicam Helios α
spectrophotometer. The UV spectra of tin(IV) were studied as a function of the chloride
concentration at five different ionic strengths, see Table A-76. The computer program
PSEQUAD [1991ZEK/NAG] was used to derive the stepwise formation constants and
the individual spectra of the chlorido complexes.
CHEMICAL THERMODYNAMICS OF TIN, ISBN 978-92-64-99206-1, © OECD 2012