Kr

Krypton

Identification

CAS Number: 7439-90-9

Discovery Year: 1898

Discoverer: Sir William Ramsey, M.W. Travers

Discovery Location: Great Britain

Properties

Atomic Mass: 83.798 →Density: 0.0034249999999999997 g/cm³ →

Crust Abundance: 0.0001 mg/kg

Crystal Structure: FCC

Atomic Dimensions

Atomic Radius (Rahm): 212 pm

Covalent Radius: 115.99999999999999 pm →

Van der Waals Radius: 202 pm

Atomic Volume: 32.2 cm³/mol

Lattice Constant: 5.72 Å

Thermodynamics

Melting Point: 116.6 K →Boiling Point: 120.85 K →Specific Heat: 0.247 J/(g·K) →Thermal Conductivity: 0.0095 W/(m·K) →Heat of Vaporization: 9.05 kJ/mol →

Electronic Structure

Electron Config: [Ar] 3d10 4s2 4p6

Block: p

Period: 4 →Group: 18 →

Oxidation States: 0

Abundance & Geochemistry

Crust Abundance: 0.0001 mg/kg

Sea Abundance: 0.00021 mg/L

Geochemical Class: volatile

Goldschmidt Class: atmophile

About

Colorless gaseous element, belongs to the noble gases. Occurs in the air, 0.0001% by volume. It can be extracted from liquid air by fractional distillation. Generally not isolated, but used with other inert gases in fluorescent lamps. Five natural isotopes, and five radioactive isotopes. Kr-85, the most stable radioactive isotope, has a half-life of 10.76 years and is produced in fission reactors. Practically inert, though known to form compounds with Fluorine.

Isotopes

Kr-84 84 56.99%

Kr-86 86 17.28%

Kr-82 82 11.59%

Kr-83 83 11.50%

Kr-80 80 2.29%

Kr-78 78 0.3550%