TABLE 9-1 Physical and Chemical Properties of Some Manganese Compoundsa

Chemical

Manganese

Manganese Chloride

Manganese Sulfate

Manganese Acetate

Manganese Dioxide

Formula

Mn

MnCl2

MnSO4

Mn (CH3COO)2

MnO2

Molecular weight

54.94

125.84

151

173

86.94

Percent manganese

100%

43.66%

36.38%

31.75%

63.19%

Solubility in water

Decomposes slowly

723 g/L at 25°C

529 g/L at 5°C

970 g/L at 25°C

Insoluble

General form

MnCl2·4H2O

MnSO4·H2O

MnAc·4H2O

 

Molecular weight

 

197.91

169

245

 

Percent manganese

 

27.76%

32.50%

22.40%

 

aOther common manganese-containing inorganic compounds, such as potassium permanganate (KMnO4), and other compounds, such as the tetraoxides, carbonate, and nitrates of manganese, are not included here.

Sources: Data from Aldrich Company 2006; Bingham et al. 2001; Merck 1989.

have been reported to interact with Mn+2 or depend on Mn+2 for either catalysis or regulatory properties. Thus, it plays an important role in energy metabolism, bone mineralization, protein and energy metabolism, and the metabolic regulation of several enzymes. Manganese has been reported to activate transferases, decarboxylases, and hydrolases (Wedler 1994). It is also an integral part of mitochondrial superoxide dismutase (thereby playing a role in the protection of free superoxide radical species), carboxylase, and liver arginase (NRC 1989).

Food is the major source of manganese, and different foods vary widely in manganese concentration. Nuts and grains contain a high concentration (18-46 parts per million [ppm]) (IOM 2001). For example, Greger (1999) reported that the average intake from Western and vegetarian diets was in the range of 0.7-10.9 mg/d. Milk products contain about 4 ppm. Other investigators have reported various values. The estimated dietary intakes of several nutritional elements for specific age groups have been reported in the U.S. Food and Drug Administration’s (FDA’s) Total Diet Study and updated at various times (1974-1982, 1982-1984, 1982-1986, 1982-1989, 1982-1991, and 1991-1997). Ac-



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