Sodium Peruranates

The compound (Na₂O₂)₂.UO₄.8H₂O is prepared in the same way as the potassium salt. It gradually separates from the concentrated solution without the addition of alcohol, and forms yellow needle-shaped crystals. If only a small quantity of the alkali is present, the addition of alcohol first precipitates a deep red oil which gradually becomes crystalline and has the composition Na₂O₂.(UO₄)₂.6H₂O. The solution of sodium peruranate gradually undergoes decomposition, hydrogen peroxide being liberated. Like most peruranates, it yields ozonised oxygen when treated with concentrated sulphuric acid. The following thermal value for the reaction has been given:

(Na₂O₂)₂.UO₄ + 3H₂SO₄ = 2Na₂SO₄ + UO₂SO₄ + 3H₂O + O₃ + 36,500 calories.

A salt of composition, Na₂UO₅.5H₂O, has been prepared.

Complex derivatives of uranium tetroxide with salts of both inorganic and organic acids have been described. When a solution containing equivalent quantities of sodium pyrophosphate and sodium uranyl pyrophosphate is treated with hydrogen peroxide the compound Na₄P₂O₇.(UO₄)₂.18H₂O is obtained; similarly a solution of ammonium uranyl carbonate yields the compound (NH₄)₂CO₃.UO₄.2H₂O.

A peroxyfluoride, 3(UO₄.KF).UO₃F₂.KF.4H₂O, has also been obtained.