Want to know why is gold yellow? (Chemistry)

[Lino1406]

The e-booklet "why is gold yellow?"
is available. 5 pages. $5
Give an e-mail

 

[grance]

LOL you should make it $50 you'll sell the same amount.

 

[Lou]

Bit of a negative nancy today, aren't we?

$5 for a good, easily understood explanation of relativistic effects is a great deal. Of course it's a bad deal if you just like taking things for granted and have zero curiosity in the physical underpinnings of your reality. Different strokes for different folks I suppose.

 

[grance]

Yeah I guess I was it was suppose to sound funny but ended up just sounding mean. I did a bit of reserch last night about it the answers are not hard to find and sorry for being rude Lino1406

 

[Lino1406]

Elementary, dear Grance. I presume now that
explaining why thin gold is transparent to green
would be a piece of cake?

 

[grance]

If I felt like looking it back up I could I didnt read much about it after all it was like 4 am but I read enuff to know I found it

 

[kadriver]

Elementary, dear Grance. I presume now that
explaining why thin gold is transparent to green
would be a piece of cake?

How thin? A few atoms thin? Atoms are mostly empty space.

I read somewhere once that if the nucleus of a hydrogen atom was sized up to the diameter of a golf ball, then the electron would be some 400 to 600 meters away whirling around at incredible speed.

I can see why any thing a few atoms thick would be transparent.

I went to a talk given at the Citadel (military college) here in Charleston SC given by Valerie Halyo of Princeton University. She is one of the researchers at CERN with the LHC (Large Hedron Collider) in Europe.

She was explaining the discovery of the Higgs Boson - a particle believed to give all matter, even electrons, mass.

In her talk she mentioned working with pure lead that was so thin you could see through it.

At the reception before the talk, we got to speak with Valerie. There were many smart people in that room. I was the only lowly undergrad in the room (except two Citadel Cadets) - I felt very small but it was a facinating experience and I learned that metal can be made so thin that it becomes transparent.

kadriver

 

[Lino1406]

Thanks for sharing that experience!
100 nm gold and below will let the green light pass.
Lead will transmit the whole spectrum

 

[gold4mike]

I bought Lino's earlier e-booklet and it's much like his posts on the forum. Very few wasted words with very much information provided.

I would expect, at five pages, this one will be the same way - 20 pages of information in 5 pages.

 

[Harold_V]

Thanks for sharing that experience!
100 nm gold and below will let the green light pass.
Lead will transmit the whole spectrum

Lino,
Can you explain the reason molten gold has the same green cast? It is something I witnessed for years on end, but could never explain. My lack of education in chemistry doesn't help.

Thanks for anything you care to offer.

Harold

 

[Lino1406]

I assume the reason is gold vapor, where gold is in the
form of Au2 (like e.g. H2). Therefore the s (or sigma)
orbit becomes full and the green absorption, based on
empty s-position is cancelled (hence green is reflected
to a bigger extent).

 

[Harold_V]

Thanks, Lino.
I am of the opinion that viewing pure gold in the molten state is one of the pleasures and well deserved rewards of refining properly. I can honestly say I never got tired of seeing it being melted.

Harold

 

[Lou]

That is the truth for myself as well.

 

[Palladium]

It radiates a certain glow that is irresistible to look at. Almost mesmerizing!

 

[g_axelsson]

Harold, I have a possible explanation of the green tint that gold gets when melted.

All objects sends out a continuous light spectra when hot (black body radiation), the hotter the object is the whiter the light. This is also true for molten gold, but the color of the light from gold comes from more than the surface, it also comes from just below the surface and that light is basically shining through a thin layer of gold and gets that green tint that transmitted light gets. That could explain why molten gold looks green.

I don't believe that gold vapors could color the light of molten gold. If there were so much vapors above the surface then we would have really big melt losses, we usually have a torch blowing on the molten gold and that would remove any vapors effectively.
There is also no reason for the vapors to have the same physical properties as the solid phase, just as colloidal gold can have a number of red to blue hues. One thing that affects the color of gold is the metal bonds with free electrons, but in a vapor the energy levels (colors) are severely affected by the physical size of the atoms.

An easy test to see if there is any vapors contributing to the color, melt some gold with a torch and compare the color where the torch is blowing on the gold with the back side. If the gold is giving off vapors then it should be more heavy at the back side and almost none where the torch is blowing on the gold.

/Göran

 

[DONNZ]

But the color can be changed to suit your fancy:

http://www.bbc.co.uk/news/uk-england-hampshire-20067736

 

[Lino1406]

Thanks,
the manipulation of nanogold colors is dealt with in
my vaster work "Gold electronic enigma, 1, 2 or 3"
of which "Why is gold yellow" is an extract. We can't
miss observing the fact that the various reactions
we get show those questions are not trivial and bear
connections to actual issues of materials and space
sciences.

 

[GOLDWORX INC]

The e-booklet "why is gold yellow?"
is available. 5 pages. $5
Give an e-mail

There's kind of an easy answer. Take 70%copper, 30%zinc. You get yellow brass. I've smelted many metals over the years, a lot of gold in all states and purities, and there's one conclusion I can tell you for sure- it's copper that gives gold the yellow colour, lead that gives it weight and maleability. Throw in a couple of other mysterious elements and BANG !!, you got synthetic gold !! Just think about that yellow brass for a minute, it's near resemlence to the colour of gold, that should get you thinking. Gabor J. Kadar GOLDWORX INC. on F-Book.

 

[its-all-a-lie]

The e-booklet "why is gold yellow?"
is available. 5 pages. $5
Give an e-mail

There's kind of an easy answer. Take 70%copper, 30%zinc. You get yellow brass. I've smelted many metals over the years, a lot of gold in all states and purities, and there's one conclusion I can tell you for sure- it's copper that gives gold the yellow colour, lead that gives it weight and maleability. Throw in a couple of other mysterious elements and BANG !!, you got synthetic gold !! Just think about that yellow brass for a minute, it's near resemlence to the colour of gold, that should get you thinking. Gabor J. Kadar GOLDWORX INC. on F-Book.

:shock: :roll: :shock:

 

[nickvc]

The e-booklet "why is gold yellow?"
is available. 5 pages. $5
Give an e-mail

There's kind of an easy answer. Take 70%copper, 30%zinc. You get yellow brass. I've smelted many metals over the years, a lot of gold in all states and purities, and there's one conclusion I can tell you for sure- it's copper that gives gold the yellow colour, lead that gives it weight and maleability. Throw in a couple of other mysterious elements and BANG !!, you got synthetic gold !! Just think about that yellow brass for a minute, it's near resemlence to the colour of gold, that should get you thinking. Gabor J. Kadar GOLDWORX INC. on F-Book.

I hate to break the bad news to you but if gold is 99.99% pure where does copper come into the equation, following that comment you state that it's lead that makes gold heavy and malleable, that is complete tosh, try working a gold alloy with lead in it and it cracks and fractures ask any goldsmith.
I suggest you do some serious reading before making inaccurate statements that others may believe who know no better.