Preparation of potassium manganate
10 g of powdered potassium permanganate are added to a solution of 10 g of potassium hydroxide in 10 ml of water contained in a small evaporating dish. The mix ture is now cautiously heated on a hot plate or a tiny flame and stirred constantly with a thermometer. It is advisable to mount an inverted powder funnel over the vessel during heating to minimize the possibility of accidental spurting and contamination by dust (to form MnO2); the thermometer is placed in the neck of the funnel for stirring. The temperature of the mixture is maintained in the range of 120-140° C until the purple color has changed to a pure deep green, as judged by drawing a drop up the side of the dish with the thermometer; the reaction requires 10-15 minutes. During the heating, the product separates as a black, coarse solid; the careful addition of a few milliliters of water may be required within the reaction period if evaporation has been excessive. The contents of the beaker are cooled and a cold solution of 10 g of potassium hydroxide in 10 ml of water is stirred in; then the mixture is cooled thoroughly in an ice-salt bath to 0° C. After standing for 15 minutes, the product is filtered off through a hardened paper, a sintered glass funnel, or a Gooch crucible with asbestos mat. The crystals are thoroughly drained free of mother liquor and then spread on a porous plate in a vacuum desiccator over solid alkali to dry. The material, which is deliquescent, should be preserved in a tightly sealed vessel. The yield of potassium manganate 12 g.
Inorganic laboratory preparations, by G. G. Schlessinger, 37-38, 1962
Potassium manganate, 10294-64-1, dipotassium dioxido(dioxo)manganese, ACMC-1BUXV, AC1L4OHV, AC1Q1TRK, UNII-5PI213D3US, 217654_ALDRICH, 5PI213D3US, CTK3J1990, XKYFHUXZPRFUTH-UHFFFAOYSA-N, dipotassium dioxomanganesebis(olate), EINECS 233-665-2, 5203AF, AR-1I6192, AR-1I6193, AKOS015915821, IN002386, IN006045, Manganic acid (H2MnO4), dipotassium salt, RT-000123, Manganic acid (H2MnO4), potassium salt (1:2), 3B4-3958, I14-53839
Potassium manganate(VI), CID160931, 110688-58-9, 110703-94-1