Hydrolysis of (CH3)2Sn2+ in Different Ionic Media: Salt Effects and Complex Formation

The hydrolysis of (CH 3 ) 2 Sn 2+ was studied potentiometrically, in different aqueous media (sodium and tetramethylammonium chlorides, sodium nitrate, sodium perchlorate, and sodium sulfate), in a wide range of ionic strength, at t = 25 °C. Least squares calculations are consistent with the formation of the species [M(OH)] +, [M(OH) 2 ] 0, [M(OH) 3 ] -, [M 2 (OH) 2 ] 2+, and [M 2 (OH) 3 ] +, with M = (CH 3 ) 2 Sn 2+ . The dependence on ionic strength for different salt solutions was taken into account by using a Debye−Hückel type equation. Medium effects were explained by considering the formation of the chloride and sulfate complexes, [(CH 3 ) 2 SnCl] +, [(CH 3 ) 2 SnCl 2 ] 0, [(CH 3 ) 2 Sn(OH)Cl] 0, [(CH 3 ) 2 Sn(OH) 2 Cl] -, [(CH 3 ) 2 Sn(SO 4 )] 0, [(CH 3 ) 2 Sn(SO 4 ) 2 ] 2 -, [(CH 3 ) 2 Sn(OH)(SO 4 )] -, and [(CH 3 ) 2 Sn(OH) 2 (SO 4 )] 2 - . Thermodynamic hydrolysis constants of (CH 3 ) 2 Sn 2+ and formation constants of the complex species with chloride and sulfate ions are reported.