An alternative structure of Pu{sub 4}O{sub 9} (''PuO{sub 2.25}'') incorporating interstitial hydroxyl rather than oxide

Bond length/bond strength relationships are applied to the Pu{sub 4}O{sub 9} ('PuO{sub 2.25}') 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 PuO{sub 2}. Substitution of hydroxyl for oxide accounts for the 'excess' oxygen content of PuO{sub 2.265,} yielding PuO{sub 2}(OH){sub 0.249.} The short range, local order (structure) of the 'Pu{sub 4}O{sub 9}' entity is alternatively formulated as Pu{sub 4}O{sub 8}OH.