Thallium, Tl,is a chemical element of group III of the periodic system of elements of D. I. Mendeleyev. Serial number 81, atomic weight 204,37. Silvery-white metal, temperature melting 303,5 degrees, the density 11,85. The connection is one - and trivalent. Thallium and its compounds are used for the manufacture of glass, fluorescent paints, solar cells, a poison for rodents (calipash), in preparations for removal of hair, etc.
Compounds thallium - strong poisons, affecting the Central nervous system, gastrointestinal tract, kidneys, and also cause hair loss (philathropy effect).
First aid in case of poisoning - washing stomach with water with activated carbon and 0.3% solution of sodium thiosulfate. When working with thallium and its compounds necessarily the use of respirators and protective clothing; periodic medical examinations with the participation of the eye specialist dermatologist, neurologist.
The maximum allowable concentration of thallium (iodine, bromine) 0.01 mg/m3.