Page 44 - Curriculum Visions Dynamic Book

Np see Neptunium; O see Oxygen Osmium (Os)
Element 76. Osmium, a hard, brittle, grey-white metal, is the densest naturally occurring element. Osmium belongs to the transition metals in the Periodic Table.
It has a higher melting point than members of the platinum group.The solid metal is difficult to produce, but once made, it does not tarnish.The powdered form of the metal gives off a strong unpleasant smell. It was renowned for
the unpleasantness (and poisonousness)
of its odour.
Discovery
It was discovered by the English chemist Smithson Tennant in 1804.
Technology
Osmium is hard and brittle. It
once was used for filaments in
electric light bulbs, but it has now been replaced by tungsten. It now mainly makes an alloy for hardening platinum, especially in artificial body joints.An alloy of osmium and iridium is used in pen points. Osmium oxide powder helps detect fingerprints.
Geology
The native metal does not exist naturally, but an alloy called iridiosmium (a natural alloy of iridium and osmium) does exist. Otherwise, osmium is mainly found associated with platinum ores and with platinum-bearing sands.
Biology
Osmium does not occur in living things. Osmium salts, especially the tetroxide, are extremely dangerous if inhaled.
 Some pen points are made of an osmium and iridium alloy.
Key facts...
Name: osmium
Symbol: Os
Atomic number: 76
Atomic weight: 190.2
Position in Periodic Table: transition metal,
group (8) (iron group); period 6. Precious
metal
State at room temperature: solid
Colour: grey-white
Density of solid: 22.61 g/cc
Melting point: 3,033°C
Boiling point: 5,012°C
Origin of name: from the Greek word osme,
meaning smell
Shell pattern of electrons: 2–8–18–32–14–2
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