Stability of Mn

A review article by Whiting (Ref 2) on the storage stability of Mn delay compns contains 8 refs... 

Although sodium oxalate is commonly used as a primary standard, its use is recommended only when oxalate is to be determined. For best absolute accuracy As(III) oxide is recommended. The direct titration of As(III) in acid solution does not proceed readily without a catalyst, probably because of the stabilization of Mn(III) by complex formation with As(V). With potassium iodate (1 drop of0.0025 M solution) as catalyst, the potentiometric end point was found to coincide with the visual end point, using ferroin, to within 0.01%, and the accuracy, tested against pure potassium iodide, was within 0.02%. 

The stability of Mn-SOD in serum was examined. Storage of a serum sample at 4°C for 5 days had no effect on the ELISA value. Freezing and thawing of the serum sample up to five times did not cause any change in the value obtained by... 

Using the data from the worked example, comment briefly on the pH dependence of the stability of Mn(II) in aqueous solution. 

The relative stabilities of Mn and Mn in nitrite, nitrate, hydroxide, oxide and peroxide melts have recently been studied in some detail. In NaNOj and NaN02/Na202 melts, [Mn04] is favoured over [Mn04] , whereas in KNOj or KNO3 melts it is the Mn species which is favoured. In aqueous alkaline solutions of blue Mn, the concentration of OH must be at least 8 M to prevent disproportionation to [Mn04] and MnOj. 

The high efficiency by which manganese porphyrins trap HNO, and the observed stability of Mn(Por)NO but not Mn(Por) NO complexes, suggested to test Mn(III) porphyrins as agents for HNO/NO discrimination. As mentioned in a previous chapter, differently from Fe(III) porphyrins, Mn(III) porphyrins do not... 

Similarly, Mug jTHF particles of 1-2.5 nm have been prepared. Moreover, the THF molecules were replaced by tetrahydrothiophene molecules for the stabilization of Mn, Pd, and Pt nanoclusters (Figure 6.5). ... 

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