title: Study of complex formation in the manganese(II)/azide system.
abstract: The complex formation between Mn(II) cations and N(3)(-) anions was studied in aqueous medium at 25 degrees C and ionic strength 2.0 M (NaClO(4)). Data of average ligand number, n (Bjerrum's function), were obtained from pH measurements on the Mn(II)/N(3)(-)/HN(3) system followed by integration to obtain Leden's function, F(0)(L). Graphical treatment of data and a matrix solution of simultaneous equations have given the following overall formation constants of mononuclear stepwise complexes: beta(1)=4.15+/-0.02 M(-1), beta(2)=6.61+/-0.04 M(-2), beta(3)=3.33+/-0.02 M(-3), beta(4)=0.63+/-0.01 M(-4). A linear plot of log K(n) vs. (n-1) shows no change in the configuration during complex formation. Slow spontaneous oxidation of solutions to Mn(III) occurs when the N(3)(-) concentration is greater than 1.0 M.
authors.affiliation: Institute de Química, Vniversidade de São Pauto, Caixa Postal 26077, CEP 05599-970, São Paulo, Brazil.
authors.forename: H D
authors.initials: HD
authors.lastname: Moya
authors.forename: E A
authors.initials: EA
authors.lastname: Neves
authors.forename: M E
authors.initials: ME
authors.lastname: Vázquez Suárez-Iha
authors.forename: N
authors.initials: N
authors.lastname: Coichev