amalgam?

hiya dudes and duddettes!
whats zinc amalgam and why is amalgam used and not pure zinc in some experiments? does an amalgam make zinc more reactive or something? i've searched the net but I havent seen anything useful.

Reply 1

oceane

It's a Zinc-Mercury alloy - perhaps its a stronger reducing agent that zinc on its own.

Reply 2

Dr Pruss

Conventionally, Amalgam is thought of as the combination of Gold plus Mercury - as used in 'traditional' dental fillings. Gold generally thought of as inert!, will bond with liquid Mercury at room temperature to create an amalgam. A former tutor found that out the hard way when he ruined his wedding ring when playing around with liquid Mercury in his hands - also not recommended as the vapours of Hg may get inhaled. The surface of his wedding ring turned a dull grey!. To get Mercury amalgam off a wedding ring requires applied heat but I digress...............................

Zinc easily mixes with Mercury to form an amalgam. Weirdness with Iron and Mercury: lthough most metals including the noble metal Gold, and alloys, are soluble in Mercury, Iron is not. From a chemical reaction perspective, a Zinc amalgam is useful (as Zinc can be used as a reducing agent).

A Zinc amalgam is useful in aliphatic reactions: A Zinc amalgam can reduce triple bonds (eg alkylenes). An important feature of a Zinc amalgam is its ability to reduce while leaving other functional groups such as alkanols and alkanones in one piece.

Why does Zinc work better in an amalgam?.

Is it because if used in electrolysis or in ionic solutions or with ionic liquids(remeber them?) Zinc-containing amalgams exhibit high anodic charge densities .

BTW, Frank Roush et al has done work with Zinc amalgams in organic reactions eg>
http://www.umich.edu/~chemh215/W04HTML/SSG4/ssg6/refs.htm
:smile: