- #1
Loren Booda
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Besides gold, copper and tin, what metallic elements can have an other than silvered appearance, and what is the explanation for this rarity?
broomfieldjay said:"The color in the transition metals (d-block) is predominantly due to the splitting of the d shell orbitals into slightly different energy levels. As a result, certain wavelengths of energy can be absorbed by the d-block elements (with electrons jumping between these slightly different energy levels), resulting in the complement color being visible. As electrons in the outer d-shell can absorb visible wavelengths of light, transition metals appear brightly colored."
The model mentioned above involving plasma frequency works well for many optical aspects of metals especially Alkali metals like Sodium but fails for properties involving band transitions which is what causes the color of transition metals.
Maybe one then also should change the Topic "Atoms, Molecules & Solids / From the periodic table to condensed matter"? The metallic luster question was a good example of what I hoped to find under this subject title...Gokul43201 said:I believe this thread will fare better in Atomic/Solid State Physics. Perhaps, the uberlords will consider moving it ?
NoTime said:I suspect that it is a lattice effect (the way the atoms are arranged).
A lattice, with the proper arangement, can selectively pass a particular frequency (in this case color).
For example a thin sheet of gold will allow light to pass through (Blue IIRC).
So in this case the blue gets transmitted to the interior of the gold sample, where it eventually gets adsorbed, while the red and green light frequency bands get reflected. Red and green light combine to view as yellow.
Light color mixing is not the same as paint color mixing.
I didn't say that the thinness of the film affected the lattice structure. Actually, I would be saying lattice structure was not affected.ZapperZ said:Note that the "thiness" of a thin film has nothing to do with the lattice structure. The reason why a thin film of metal can allow some light to pass through is because there is a finite penetration depth for a particular frequency of light. If the film is less than the penetration depth, then that light will pass through. So this has nothing to do directly with the lattice structure - if we are comparing film and bulk having that identical structure.
Zz.
NoTime said:I didn't say that the thinness of the film affected the lattice structure. Actually, I would be saying lattice structure was not affected.
I also didn't say that I know this to be the mechanism behind metal color.
OTOH I also don't know if you are saying this is wrong.
If you are saying it is wrong then what is the correct answer?
Also since lattices are known to be involved in selective transmission of EM then wouldn't "penetration depth for a particular frequency of light" be a lattice effect?
In either case I was just saying that the blue light just penetrates too deeply to get reflected, leaving yellow as the result.
Err, I think you read too quickly. I was using the thin film to demonstrate that the penetration depth was greater for blue.ZapperZ said:I responded because you said you "suspect the lattice", but yet your explanation was due to a thin film. The reason and explanation via the example you gave didn't match.
While the lattice certain play a role in optical conductivity (I've explained this ad nauseum on here - you can do a search), it isn't the reason for the penetration depth or skin depth for a metal, or why metals are highly reflective. The conduction electrons play the most significant role in that mechanism, not the lattice.
Zz.
NoTime said:Err, I think you read too quickly. I was using the thin film to demonstrate that the penetration depth was greater for blue.
Since all metals have conduction electrons, which are generally treated as a gas. Is it the lattice structure that eventually imposes the ordering on the gas that makes it exhibit different properties? Or is there some other ordering mechanism? Or a combination of different mechanisms?
Gokul43201 said:... Due to the large number (density) of free electrons in most metals, the dielectric constant, K is negative (up to a certain frequency called the plasma frequency). A negative K gives rise to an imaginary wave number, ( n ~ sqrt(K) ) and hence 'no' transmission (due to an exponentially decaying field within the metal). The plasma frequency for most metals is somewhere in the far UV range. ...
In short, the color of the metal depends on the frequency dependence of the dielectric constant in the Visible range.
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Some examples of metallic elements with a lustrous appearance are gold, silver, copper, platinum, and iron.
An element is considered to have a lustrous appearance if it reflects light and has a shiny, reflective surface.
Metallic elements have a lustrous appearance due to their high electrical and thermal conductivity, as well as their ability to reflect light.
Metallic elements with a lustrous appearance are used in a wide range of everyday items, such as jewelry, coins, electronics, and kitchenware.
While metallic elements with a lustrous appearance are generally safe to use, some may be toxic in certain forms. For example, mercury, which has a lustrous appearance, can be harmful if ingested or inhaled. It is important to handle and dispose of these elements properly to avoid any negative effects.