Hydrolysis of methyltin(IV) trichloride in aqueous NaCl and NaNO3 solutions at different ionic strengths and temperatures

✍ Scribed by Concetta De Stefano; Claudia Foti; Antonio Gianguzza; Francesca Marrone; Silvio Sammartano

• Publisher: John Wiley and Sons
• Year: 1999
• Tongue: English
• Weight: 87 KB
• Volume: 13
• Category: Article
• ISSN: 0268-2605
• DOI: 10.1002/(sici)1099-0739(199911)13:11<805::aid-aoc887>3.0.co;2-w

✦ Synopsis

The hydrolysis of methyltin(IV) trichloride (CH 3 SnCl 3 ) has been studied in aqueous NaCl and NaNO 3 solutions (0 `I/mol dm À3 1), at different temperatures (15 T/°C 45) by potentiometric measurements (H -glass electrode). By considering the generic hydrolytic reaction pCH 3 Sn 3 qH 2 O = (CH 3 Sn) p (OH) q 3pÀq qH (logb pq ), we have the formation of five species and logb 12 = À3.36, logb 13 = À8.99, logb 14 = À20.27 and logb 25 = À7.61. The first hydrolysis step is measurable only at very low pH values and was not determined: a rough estimate of the hydrolysis constant is logb 11 = À1.5 (AE 0.5). The dependence on ionic strength of logb pq is quite different in NaNO 3 and NaCl solutions, and the formation at low pH values of the species CH 3 Sn(OH)Cl has been found with logb = À1.40. Hydrolysis constants strongly depend on temperature and from the relationships logb pq = f(T), DH °values have been calculated. Speciation problems of CH 3 Sn 3 in aqueous solution are discussed.