Strontium stability constant

Even though the stability constants for calcium, barium and strontium cations in nitrobenzene are much higher than that for lithium cation, the translocation of lithium ion from water to nitrobenzene is shifted by about 300 mV negatively when it is used as a base electrolyte, i.e., when [Li+(w)]>>[X(n)] and it coincides with the transfer of alkaline earth metal cation. From a comparison of the standard electrical potential difference and from the calculated half-wave potentials using the stability constant for several cations we have chosen magnesium chloride as a base electrolyte for the aqueous phase. To minimize the base electrolytes current in DPSV we have decreased their concentrations. In the case of magnesium chloride it was 2.5 mM solution in water and 5 mM solution of TBATPB in nitrobenzene. The concentration of the ionophore was 1 mM. 

There have only been a few studies on the hydrolysis of strontium(II), and all of these were undertaken many years ago. In addition, the data were corrected to zero strength in the studies in which the stability constants were determined, even though they may have been calculated from previously published data. There are even fewer studies where the stability constant of SrOH has been reported in solutions of fixed ionic strength. 

Data reported for the stability constant of BaOH are listed in Table 7.24. As with strontium(II), the data cover only a relatively small range of temperature (5-45 °C). There are few data that have been obtained in media that are fixed at high ionic strength, most likely due to the low stability of the species. The majority of data that were obtained at fixed ionic strength were at low concentration and were corrected to zero ionic strength by the authors or in subsequent studies. 

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