Manganese(II) sulfate Manganese(II) sulfate Manganese(II) sulfate usually refers to the inorganic compound with the formula MnSO·HO. This pale pink deliquescent solid is a commercially significant manganese(II) salt. Approximately 260 thousand tonnes of manganese(II) sulfate were produced worldwide in 2005. It is the precursor to manganese metal and many other chemical compounds. Mn-deficient soil is remediated with this salt. Like many metal sulfates, manganese sulfate forms a variety of hydrates: monohydrate, tetrahydrate, pentahydrate, and heptahydrate. The monohydrate is most common. All of these salts dissolve to give faintly pink solutions of the aquo complex [Mn(HO)]. The pale pink colour of Mn(II) salts is
Manganese alloyed with manganese was harder but not more brittle. In 1837, British academic James Couper noted an association between miners' heavy exposure to manganese with a form of Parkinson's disease. In 1912, United States patents were granted for protecting firearms against rust and corrosion with manganese phosphate electrochemical conversion coatings, and the process has seen widespread use ever since. The invention of the Leclanché cell in 1866 and the subsequent improvement of batteries containing manganese dioxide as cathodic depolarizer increased the demand for manganese dioxide. Until the development of batteries with nickel-cadmium and lithium, most batteries contained manganese. The zinc-carbon