An Amalgam is an alloy of mercury with another metal.
It may be a liquid, a soft paste or a solid, depending upon the proportion of mercury.
These alloys are formed through metallic bonding, with the electrostatic attractive force of the conduction electrons working to bind all the positively charged metal ions together into a crystal lattice structure.
Amalgams are used to make dental fillings, to bind to precious metals so they can be isolated later, and to produce mirror coatings.