| When potassium fluoroxymolybdate MoO2F2.2KF.H2O is dissolved in warm hydrogen-peroxide solution, oxidation occurs, and on cooling, fine yellow laminae, of composition MoO3F2.2KF.H2O, separate. This salt reduces potassium permanganate in dilute sulphuric acid solution, with evolution of oxygen. Corresponding caesium and rubidium salts have also been obtained. A solution of ammonium paramolybdate in hydrofluoric acid, when treated with hydrogen peroxide in presence of excess ammonium fluoride, yields on evaporation the compound MoO3F2.3NH4F, which may also be obtained by the direct action of hydrogen peroxide on the fluoroxymolybdate MoO2F2.3NH4F. By the further action of hydrogen peroxide on the potassium salt, the compound MoO4.2KF.H2O may be obtained. |