12-07719. Polonium Dioxide [Archived]

Nomenclature

CAS number: 7446-06-2
O2Po; mol wt 240.98.
O 13.28%, Po 86.72%.
PoO2.

Description and references

Formed from the elements at 250°: Martin, J. Phys. Chem. 58, 911 (1954).

Properties

Two crystal modifications: yellow, low temperature form, face-centered cubic symmetry; red, high-temperature form, tetragonal symmetry. Darkens in color on heating, chocolate brown at sublimation temp of 885°. Dec into the elements at 500° under vacuum; slowly reduced to the metal in hydrogen at 200°. Heat of formation ≈30 kcal/mole. Sol in aq solns of ammonium carbonate, phosphoric acid.

Status

This monograph has been retired and is no longer subject to revision or update.