Molecules and bonds of transition metals

[KingNothing]

What about the molecules and bonds of transition metals make them (such as gold) such good conductors? I'm in AP chemistry, so we may have gone over it, but I don't know right now.

 

[Gokul43201]

Actually, more important is the existence of a large density of free electrons in metals which contributes to large thermal conductivities at room temperature.

 

[chem_tr]

We explain this phenomena with band theory; conducting and valence bands are very close to each other, providing rapid crossings with relatively low energy. Insulators are very low conductors, since the gap is too high for any electron to be excited.

 

[ZapperZ]

What about the molecules and bonds of transition metals make them (such as gold) such good conductors? I'm in AP chemistry, so we may have gone over it, but I don't know right now.

Not sure why this question is in the Chemistry section rather than the Condensed Matter section, but anyhow...

The major reason why the transition elements are such good conductors is because the valence shell for these elements is the d-orbitals. This orbital extends very far out from the nucleus of the atom (look at the average position of an electron in the 3d orbital when compared to the 4s). When atoms of these elements are "locked" into place in a solid, the d-orbitals have a larger tendency to overlap and hybridize with their neighbors (nearest neighbors and even next nearest neighbors), forming the familiar conduction bands.

Some transition metals, however, have other "complications" that are way beyond simple band structure description (such as the Mott-Hubbard description). So always read this with a caveat in mind.

Zz.

 

[The Bob]

While doing my physics work on the tungsten in a filament I came across this website which shows all of the conductivity and resisitivites of the transistion metals http://www.allmeasures.com/Formulae/. This is just for anyone's general interest.

I believe Silver is the best at conducting electricity but I haven't checked too much. I know that Silver is better than Gold, Tungsten, Magnesium, Iron, Calcium, Ruthenium and Zicronium at conducting.

The Bob (2004 ©)

 

[chroot]

Silver is, indeed, the best elemental metal in electrical conduction. The problem is that silver rapidly oxidizes when exposed to air, and silver oxides are not good conductors at all.

- Warren

 

[The Bob]

Silver is, indeed, the best elemental metal in electrical conduction. The problem is that silver rapidly oxidizes when exposed to air, and silver oxides are not good conductors at all.

I see. Is there no way it can be coated in carbon or tungsten to help this problem?

The Bob (2004 ©)

 

[The Bob]

The major reason why the transition elements are such good conductors is because the valence shell for these elements is the d-orbitals. This orbital extends very far out from the nucleus of the atom (look at the average position of an electron in the 3d orbital when compared to the 4s). When atoms of these elements are "locked" into place in a solid, the d-orbitals have a larger tendency to overlap and hybridize with their neighbors (nearest neighbors and even next nearest neighbors), forming the familiar conduction bands.

Like Zz said, I believe that it is to do with the lattice and, therefore, the fact (given above) about the metal that makes it conduct well.

Graphite conducts electricity because of it's lattice but Diamond does not. Both are carbon. This shows that the structure of the metal is important. I know that silver is the best conductor of any metal and it has a shell configuration of 2.8.18.18.1. However I cannot see the significance of this at all. I suppose it could be that it has the most amount of electrons in its 4d state and the least in its 5s in repsect to its 4d state. Palladium is the only one I can see that should bet silver, because of its electron configuration.

I don't think my explanation is too good:
Silver = 2.8.18.18.1
Cadmium = 2.8.18.18.2
Copper = 2.8.18.1
Gold = 2.8.18.32.18.1

As you can see copper has few, closer-to-the-nucleus electrons and so it doesn't conduct as much as silver. Cadmium has one extra electron in the 5s state to consider and so is not as good at conducting as silver is. However from what I am saying, gold should be better. It isn't. I don't know where to go or what to say from here.

I hope this has put some ideas into some people's heads.

The Bob (2004 ©)

P.S. If it is all rubbish, please tell me nicely.