Isotope exchange between alkaline earth metal hydroxide and HTO water in the equilibrium state

Abstract

In order to reveal to what extent tritium (³H or T) can be incorporated into hydroxides, the isotope exchange reaction (OT-for-OH exchange reaction) between each alkaline earth metal hydroxide (M(OH)₂), where M means alkaline earth metal (M=Ca, Sr or Ba) and HTO water was observed homogeneously at 30 °C under equilibrium after mixing. Consequently, the followings were obtained: (1) a quantitative relation between the electronegativity of each M ion and the ability (of the M ion) incorporating OT⁻ into the M hydroxide can be found and the ability is small when the temperature is high, (2) the exchange rate for the OT-for-OH exchange reaction is small when the electronegativity of the M ion in the M hydroxide in great, (3) as for the dissociation of HTO water, it seems that fomula (HTO⇆T⁺+OH⁻) is more predominant than the fomula (HTO⇆H⁺+OT⁻) when the temperature is high and (4) the method used in this work is useful to estimate the reactivity of a certain alkaline material.