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Name: Platinum
Symbol: Pt
Atomic number: 78
Atomic weight: 195.078 (2)
CAS Registry ID: 7440-06-4
Group number: 10
Group name: Precious metal or platinum group metal
Period number: 6
Block: d-block
Standard state: solid at 298 K
Colour: greyish white
Platinum is a beautiful silvery-white metal, when
pure, and is malleable and ductile. It has a coefficient
of expansion almost equal to that of soda-lime-silica
glass, and is therefore used to make sealed electrodes
in glass systems.
The metal does not oxidise
in air. It is insoluble in hydrochloric and nitric
acid, but dissolves when they are mixed as aqua
regia, forming chloroplatinic acid (H2PtCl6),
an important compound. It is corroded by halogens,
cyanides, sulphur and alkalis
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