Viewing a single comment thread. View all comments

Lepmuru t1_ixu9jwp wrote

Reply to comment by Effective-Night-2646 in Does the formation of bonds mean a chemical reaction has occurred? by Effective-Night-2646

Metal bonds are a bit out of my area of expertise, as I am a biochemist and usually only encounter metals in my field sporadically.

Maybe someone in anorganic chemistry or material science can give us their view here? And please do correct me if I'm wrong.

As far as I understand, metal bonds are in a way similar to ionic bonds, in that bonding electrons are completely ripped from their atoms, but do not reside with the ion that took them. Rather, they are distributed and moveable throughout a crystal structure of the ions.

As to the question if metal alloys are classified mixtures - I do not know. I am inclined to believe they are not, but as I said, metal chemistry is beyond my area of expertise. Edit: u/passerculus elaborated on the nature of metal bonds. Refer to their comment for info about that, rather than my half knowledge!

2

passerculus t1_ixusia1 wrote

Metallurgy and inorganic chemistry quickly blends into condensed matter physics.

Metals and semiconductors will arrange themselves in specific crystal structures that depend on their electron valence. In the crystal the outermost electrons tend to get shared collectively. What that looks like is the energy levels that once belonged to the discrete atoms blend together to form bands. The band that corresponds to the original valence orbitals is called the valence band, and the next higher the conduction band.

The difference between metals and semiconductors is in the latter there is an energy gap between the bands, where in a metal the band energies meet at specific points in the crystal. Think of them as two sets of roads, local streets and a highway system. In a metal there are plenty of on-ramps and the electrons can move all about the crystal.

In a semiconductor there are no on-ramps, so the local streets are totally log-jammed and electrons stay stuck in place. If you manage get rid of a valence bad electron (e.g. thermally kick it up to the conduction band) there is now a little wiggle room and electrons can hop from atom to atom in the crystal.

TL,DR its sort of like covalent bonds, but instead of molecular orbitals they are really big

7