Multiply charged metal ions

Multiply charged metal ions have not received much attention due in part to the belief that rapid charge exchange would occur exclusively. Taking a lead from a study by Tonkyn and Weisshaar on Ti " " (44), we have begun to study a series of doubly charged early transition-metal ions. Nb (2nd IP(Nb) - 14.3 eV) is observed to react with methane (IP - 12.6 eV) not only by charge transfer. 

The advent of ESI in the 1990s opened the door to a more effective approach to condensed-phase/solution chemistry and allowed for the examination of hydration, solvation, and complexation of rare earths and actinides, including with multiply charged metal ions. By controlling the composition of the solution, it is possible to produce a variety of metal ion complexes coordinated by diverse covalently and datively bound neutral ligands, as well as by various counterions. In the case of the actinides, the robust and important uranyl ion, U02, has been a prime focus in the studies of actinide chemistry in solution and gas as explored by ESI. Ion spectroscopy, profiting from new powerful light sources, accompanied the development of ion chemistry studies based on ESI. 

A comparative study of spark-ablation ICP-MS and GD-MS in the case of steel has been reported by Jakubowski and coworkers [536, 613], The RSFs for a number of trace elements and the measurement precision are very similar in both cases. Steel analysis by GD-MS benefits from the addition of 1% of H2 to the Ar discharge gas [614], the explanation for which is certainly complex. For certified reference steels, including superalloys, reliable analysis results can be obtained. The determination of Mo, Nb and Zr in steels by GD-MS was found to be affected by the formation of multiply-charged cluster ions (metal argides) [615]. A correction based on the assumption that the rate of formation of the singly-charged argide is the same for all analytes and coincident with that of FeAr+ was used. The capabilities of low resolution GD-MS were shown by the example of steel analysis [616], where detection limits were down to 1 ng/g and up to 30 elements could be determined. 

Many metal ions react with water to produce hydrolysis products that are multiply charged inorganic polymers. These may react specifically with negative sites on the colloidal particles to form relatively strong chemical bonds, or they may be adsorbed at the interface. In either case, the charge on the particle is reduced. 

---