Manganese Oxides

Manganese is an essential element to both plants and animals. Much of the Mn in soils occurs in the form of Mn oxides. These Mn oxides contribute to many important properties of soils and to certain chemical reactions of environmental importance, both favorable and unfavorable. This chapter presents the Mn oxides frequently identified in soils, their occurrence, and some of their chemical, mineralogical, and physical properties and reactions of environmental interest. The discussion also covers structure, composition, morphology, abundance, distribution, and formation of manganese oxides. Manganese is the 12th most abundant element in the Earth's crust, and it is about one-fiftieth of the abundance of Fe that often is associated with Mn in mixtures of oxides in soils. The chapter concludes with case studies on manganese oxide oxidation of chromium and manganese toxicity potential of fly ash from a plywood mill.