Nomenclature
CAS number: 1313-13-9
Manganese binoxide; manganese peroxide; manganese superoxide; black manganese oxide.
MnO
2; mol wt 86.94.
Mn 63.19%, O 36.81%.
Description and references
Occurs in nature as the mineral pyrolusite, or made artificially (pptd). The native product is heavy,
steel-gray when in lumps, black when powdered; the pptd product is
a brownish-black, fine powder. Both usually contain some Mn3O4 and some water. When ignited evolves oxygen, leaving
Mn3O4. Lab prepn: Moore et al., J. Am. Chem. Soc. 72, 856 (1950); Covington et al., Trans. Faraday Soc. 58, 1975 (1962). Toxicity
study: D. J. Holbrook, Jr. et al., Environ. Health Perspect. 10, 95 (1975).
Review of use as reagent: J. S. Pizey, Synthetic
Reagents vol. 2 (John Wiley, New York, 1974)
pp 143-174.
Properties
Tetragonal crystals (rutile structure). Insol
in water, nitric or cold sulfuric acid. Slowly dissolves in cold
HCl with evolution of Cl2; in presence of hydrogen peroxide
or oxalic acid it dissolves in dil H2SO4 or
HNO3. Strong oxidizer; should not
be heated or rubbed with organic matter or other oxidizable substances,
e.g., sulfur, sulfides, phosphides, hypophosphites, etc. LD50 orally in rats: >40 mmole/kg (Holbrook).Use
The mineral is the source of manganese and all its
compds; largely used in manuf manganese steel; oxidizer; in alkaline
batteries (dry cells); for making amethyst glass, decolorizing glass;
painting on porcelain, faience and majolica. The ppt is used in electrotechnics,
pigments, browning gun barrels, drier for paints and varnishes, printing
and dyeing textiles.