Manganese(II) nitrate Manganese(II) nitrate Manganese(II) nitrate are the inorganic compounds with formula Mn(NO)(HO). Each formula unit is composed of one Mn cation and two NO anions and varying amounts of water. Most common is the tetrahydrate Mn(NO)·4HO, but mono- and hexahydrates are also known as well as the anhydrous compound. Some of these compounds are useful precursors to the oxides of manganese. Manganese(II) nitrate is prepared by dissolving manganese(II) oxide in nitric acid: It can also be prepared from manganese dioxide and nitrogen dioxide: On heating to 300 °C, aqueous solutions of manganese(II) nitrate thermally decompose to form MnO and NO. Manganese(II)
Manganese battery and the alkaline battery normally use industrially produced manganese dioxide because naturally occurring manganese dioxide contains impurities. In the 20th century, manganese dioxide was widely used as the cathodic for commercial disposable dry batteries of both the standard (zinc-carbon) and alkaline types. Manganese comprises about 1000 ppm (0.1%) of the Earth's crust, the 12th most abundant of the crust's elements. Soil contains 7–9000 ppm of manganese with an average of 440 ppm. Seawater has only 10 ppm manganese and the atmosphere contains 0.01 µg/m. Manganese occurs principally as pyrolusite (MnO), braunite, (MnMn)(SiO), psilomelane (Ba,HO)MnO, and to a lesser extent