An alternative structure of Pu4O9 (“PuO2.25”) incorporating interstitial hydroxyl rather than oxide

Bond length/bond strength relationships are applied to the Pu4O9 (“PuO2.25”) structure proposed by others and support one Pu(V) with a central hydroxyl ion but not a central oxide ion nor formation of Pu(VI). Bond distances and bond strengths are normal for a central ion of unit charge, and reconcile the finding that cell dimensions are so minimally changed from those of PuO2. Substitution of hydroxyl for oxide accounts for the “excess” oxygen content of PuO2.265, yielding PuO2(OH)0.249. The short range, local order (structure) of the “Pu4O9” entity is alternatively formulated as Pu4O8OH.