Sciencemadness Discussion Board

What is amalgam? Is it mercuride (mercury anion)?

PKMN - 22-8-2015 at 07:32

Is it chemical compound, or alloy, or both? Google and Wikipedia do not know.
Also, are all alloys chemical compounds (e.g. brass is copper zincide)?

[Edited on 22-8-2015 by PKMN]

MeshPL - 22-8-2015 at 09:41

Some are some are not. Some amalgams (mostly alkali metals) are actual compounds with specific proprieties, but other mixtures may be just alloys. Interesting example of alloy being a compound is "purple gold" which is AuAl2. It can be used as a gemstone but is to brittle for use as a metal in jewellery.

By example iron forms several compounds and mixtures with carbon hence steel making is pretty complex.

For most alloys assume they are mixtures. For alloys with specific stochiometry and sometimes non-metallic proprieties assume they are intermetallics. Some alloys may contain several phases being different compounds, intermefallic compounds, mixtures and pure metals.

So it is complicated.

Hope I didn't overcomplicate.

Texium - 22-8-2015 at 09:48

Quote: Originally posted by PKMN  
Is it chemical compound, or alloy, or both? Google and Wikipedia do not know.
Also, are all alloys chemical compounds (e.g. brass is copper zincide)?
No, traditional alloys are not chemical compounds. Think of them as solid solutions. Just like when you dissolve something in water and it forms a uniform solution, when you mix two or more metals together and they are able to intermix (some metal combinations are not), such as copper and zinc, you obtain a solution containing the atoms of the different constituent elements evenly distributed throughout the alloy. All of the metals in an alloy are present as neutral atoms, not ions. They are not held together chemically, only physically mixed.

battoussai114 - 22-8-2015 at 10:03

Also, sometimes alloys with the same stoichiometry might have different internal configurations depending on the temperature it was treated and stuff like that. Think like how steel may be heterogeneous with "stacks" of Iron Carbide and pure Iron on its micro-structure or how it may be made of iron crystals with carbon within them in an homogeneous structure...

Marvin - 23-8-2015 at 11:14

Is methane hydrogen carbide? It's an astonishingly bad acid.

Ionic bonding, covalent bonding, metallic bonding. Bonding between metals is real bonding, they would have very low boiling points otherwise. Metallic bonding is typically a bit weaker than the other two. You can form compounds, pretty much anything that will crystallise can be argued to be a compound.