Thallium is a white, heavy and soft metal with a melting point of 303.5°C, a boiling point of1457 C and a density of 1 1.85 g/cm? .
Thallium can react with oxygen and halogen elements in the air at room temperature. It can react with sulfur, selenium, tellurium and phosphorus at high temperature; Thallium is insoluble in water and reacts slowly with hydrochloric acid, but it dissolves rapidly in nitric acid and dilute sulfuric acid to form soluble salts. Thallium halide and silver halide have similar photosensitivity, and can not only see photodegradation.
The low melting point of thallium and gold can be used to bond the glass shell of electron tube; Thallium-activated sodium iodide crystal is used in photomultiplier tube; Thallium compounds can also be used as catalysts for organic synthesis; Thallium and thallium compounds are toxic to living things and human bodies.
Precautions: Sodium chloride (non-edible salt), a by-product of firecrackers, is often red. Be careful not to buy or eat red salt.
Thallium is a chemical element with chemical symbol Tl and atomic number 8 1, which is a soft silvery white metal.
Thallium is highly toxic, which can lead to chronic or acute hair loss and even death in severe cases. To treat thallium poisoning, Prussian blue can be used to make thallium react with it to generate insoluble substances, but this dye is expensive and rarely produced. At present, there are about 100 tablets in China. Thallium was originally used as an insecticide, but because of its carcinogenicity, many countries have reduced or stopped using thallium as an insecticide.
Thallium is also used as an infrared detector.
Overall characteristics
Name, symbol, serial number thallium, Tl, 8 1
Series weak metals
Series, period, element partition 13 series (IIIA), 6, p
Density and hardness11850kg/m3, 1.2.
The color and appearance are silvery white.
Crustal content is 3× 10-5%
Atomic properties
Atomic weight 204.3833 atomic weight unit
Atomic radius (calculated value) 190( 156)pm
* * * Price radius 148 pm
Van der Waals radius 196 pm
Valence electron configuration [xenon] 4f145d106s26p1.
The electron arrangement of each energy level is 2,8,18,32,18,3.
Oxidation value (oxide) 3, 1 (weakly alkaline)
Hexagonal crystal structure
physical quality
Material state solid state
Melting point 577 k (304 c)
Boiling point1746 k (1473 c)
The molar volume is 17.22× 10-6m3/mol.
Heat of vaporization 164. 1 kJ/mol
Heat of fusion 4.142kJ/mol.
The vapor pressure is 5.33× 10-6 Pa (577K).
The speed of sound is 818m/s (293. 15K).
Other attributes
Electronegativity 1.62 (Pauling scale)
Specific heat capacity129j/(kg k)
The electrical conductivity is 6. 17× 106/ (m ohms).
The thermal conductivity is 46.1w/(m k)
The first ionization energy is 589.4 kJ/mol.
The second ionization energy is 197 1 kJ/mol.
The third ionization energy is 2878 kJ/mol.