Osmium - Periodic Table of the Elements

FACULTY OF CHEMICAL TECHNOLOGY IN SPLIT
PERIODIC TABLE OF THE ELEMENTS version 1.7


 Os

English:  Osmium
French: Osmium
Croatian: Osmij
German: Osmium
Italian: Osmio


Atomic number: 76
Group numbers: 8
Period: 6
Standard state (20 °C): solid

Osmium was discovered by Smithson Tennant (England) in 1803. The origin of the name comes from the Greek word osme meaning smell. It is hard fine black powder or hard, lustrous, blue-white metal. Unaffected by air, water and acids. Characteristic acrid, chlorine like odour due to tetroxide compound. Osmium tetroxide highly toxic.

Electronic configuration: [Xe] 4f¹⁴ 5d⁶ 6s²
Relative atomic mass: 190.23(3)
Formal oxidation number: +3 +4

Electronegativities: 2.2
Thermal conductivity: 87.6 W/(m K)
Electrical resistivity (20 °C): 9.5 μΩcm

Atomic radius: 133.8 pm
Density (g/dm3): 22590 (293 K) 
20100 (m.p.)
Molar volume (cm3/mol): 8.42 (293 K) 
9.46 (m.p.)

Melting point: 3033 °C
Boiling point: 5012 °C
Critical temperature: 12427 °C

Heat of fusion: 29.3 kJ/mol
Heat of vaporization: 738.06 kJ/mol
Heat of atomization: 791 kJ/mol

Osmium is obtained from the same ores as platinum. Used to tip gold pen points, instrument pivots, to make electric light filaments. Used for high temperature alloys and pressure bearings. Very hard and resists corrosion better than any other. The price of 99.95 % pure osmium powder is 2159.60 € for 25 g. 75Re <= 76Os => 77Ir ___________________ If you have comments, corrections or suggestions about this site, please send me a e-mail. Periodic Table of the Elements __________________________________ Last modified: 29.03.2003 Copyright © 1998-2003 by Eni Generalic