Titration inorganic complexing reagents

Inorganic complexing reagents such as Hg(N03)2, AgNOs, NiS04 and KCN can be used for complex-formation titrations. Mercury(II) ion forms neutral complexes with most of the anions that precipitate with silver nitrate such as Br, CD, SCN, CN and thiourea. 

Another important example of a redox titration for inorganic analytes, which is important in industrial labs, is the determination of water in nonaqueous solvents. The titrant for this analysis is known as the Karl Fischer reagent and consists of a mixture of iodine, sulfur dioxide, pyridine, and methanol. The concentration of pyridine is sufficiently large so that b and SO2 are complexed with the pyridine (py) as py b and py SO2. When added to a sample containing water, b is reduced to U, and SO2 is oxidized to SO3. 

The ethereal methyllithium solutions were purchased from Alfa Inorganics. The concentration of methyllithium in such solutions may be conveniently determined by a procedure described elsewhere4,5 in which the lithium reagent is titrated with sec-butyl alcohol, utilizing the charge transfer complex formed from bipyridyl or o-phenanthroline and the lithium reagent as indicator. 

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