Valence distribution of radiophosphorus in potassium chloride single crystals. Part 1.—Initial distribution

Abstract

The importance of crystal purity and perfection in determining the oxidation state of ³²P atoms in KCl has been investigated. ³²P was produced by the reaction ³⁵Cl(n, α)³²P, using reactor neutrons. In pure single crystals, most of the ³²P appeared in the hypophosphite [P(I)] fraction on dissolution but crystals containing OH′ ion or (CO₂+ CO^2–₃) impurity showed an increase in the phosphite [P(III)] and phosphate [P(V)] fractions at the expense of P(I). Introduction of defects either by crushing or quenching prior to irradiation also increases the oxidised fractions. A mechanism of oxidation for crystals with oxygen-containing impurities is proposed: this involves formation of a short-lived, deep electron trap, possibly an O atom, by gamma radiolysis of the impurity.