Chemical element or an electrophile; similarly "Nu" denotes a nucleophile. "L" is used to represent a general ligand in inorganic and organometallic chemistry. "M" is also often used in place of a general metal. At least two additional, two-letter generic chemical symbols are also in informal usage, "Ln" for any lanthanide element and "An" for any actinide element. "Rg" was formerly used for any rare gas element, but the group of rare gases has now been renamed noble gases and the symbol "Rg" has now been assigned to the element roentgenium. Isotopes are distinguished by the atomic mass number (total protons and
Cobalt poisoning One such example was seen in an experiment involving the effects of increased cobalt concentration on tomato plants. As the dosage of cobalt in the soil surrounding the plants increased, so too did the rate of necrosis of the leaves of the tomato plant. Over time this led to an inability of the plant to produce fruit and eventually the plant died. Cobalt poisoning Cobalt poisoning is intoxication caused by excessive levels of cobalt in the body. Cobalt is an essential element for health in animals in minute amounts as a component of Vitamin B. A deficiency of cobalt, which