Red tungsten protein

Red tungsten protein, 40 72 Reduced configuration, four-iron clusters, 38 456-457... 

Cobalt is an essential element that is part of vitamin B12, or cobalamin, a coenzyme that is essential in the formation of proteins, nucleic acids, and red blood cells. Although cobalt poisoning is not common, excessive levels can be harmful. Most cases of human exposure to toxic levels of cobalt have occurred through inhalation in the workplace. Many exposures have been suffered by workers working with hard metal alloys of cobalt and tungsten carbide, where very fine particles... 

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