Osmium

Symbol: Os
Date of discovery: 1803
Name origin: Greek osmë
Appearance: blue-white
Discoverer: Smithson Tenant
Obtained from: platinum ores

Melting point: 3306 K
Boiling point: 5285 K
Density[kg/m³]: 22610
Molar volume: 8.42 × 10^-6 m³/mol
Protons/Electrons: 76
Neutrons: 114
Shell structure: 2,8,18,32,14,2
Electron configuration: [Xe]4f145d66s2
Oxidation state: 3,4
Crystal structure: hexagonal

Discovered by S. Tenant in 1803 from the residue of crude platinum, this lustrous, blue-white metallic element is extremely hard and brittle, even at high temperatures. The densest of all elements, osmium has the highest melting point and lowest vapor pressure of the platinum group. While the metal form is often difficult to isolate, osmium powder can be sintered at high temperatures. This powder gives off a highly toxic, strong-smelling tetraoxide, giving osmium its Greek origin namesake "osme", meaning odor.