Note 66 — Chapter XX · SULPHUR, SELENIUM, AND TELLURIUM

If this be true one would expect the following peroxide hydrates: for phosphoric acid, (H2PO4)2 = H4P2O8 = 2H2O + 2PO3; for carbonic acid, (HCO3)2 = H2C2O6 = H2O + C2O5; and for lead the true peroxide will be also Pb2O5, &c. Judging from the example of barium peroxide (Note 62), these peroxide forms will probably combine together. It seems to me that the compounds obtained by Fairley for uranium are very instructive as elucidating the peroxides. In the action of hydrogen peroxide in an acid solution on uranium oxide, UO3, there is formed a uranium peroxide, UO4,4H2O (U = 240), but hydrogen peroxide acts on uranium oxide in the presence of caustic soda; on the addition of alcohol a crystalline compound containing Na4UO8,4H2O is precipitated, which is doubtless a compound of the peroxides of sodium, Na2O2, and uranium, UO4. It is very possible that the first peroxide, UO4,4H2O, contains the elements of hydrogen peroxide and uranium peroxide, U2O7, or even U(OH)6,H2O2, just as the peroxide form lately discovered by Spring for tin perhaps contains Sn2O3,H2O2.