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Is it true that heavy water is not blue?

Based on your description, I may have found the article you originally saw, or at least one very similar. Researchers from Dartmouth College published a paper$\mathrm{^1}$ in which they report, among ...
airhuff's user avatar
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72 votes

Is it true that heavy water is not blue?

This does seem to be the case. I don't have images of the different types of water, but I did find this overlaid IR-visible spectrum of water and heavy water: As you stated, the presence of deuterium ...
Tyberius's user avatar
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27 votes
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What makes ABS plastic turn yellow?

What you're specifically describing is typically known as UV degradation. The color change is due to the oxidation of the polymers that make up the plastic. These chemical reactions are demonstrated ...
oceandevil24's user avatar
26 votes

Can flames be colored black?

This video shows how a black flame is achieved. If you illuminate the fire with a monochromatic light source (sodium vapor lamp) and introduce a species in the fire that absorbs that wavelength (...
This random guy's user avatar
26 votes
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What gives fresh milk a yellow tinge?

The main substances that cause the yellowish color of the milk are carotenoids [1]. The main carotene involved is the beta-carotene coming from the feed that cows eat. Some studies have been carried ...
G M's user avatar
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25 votes
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Soaps come in different colors, but why is soap lather always white?

Though @DHMO's answer is quite interesting, you shouldn't take it without a pinch of salt. I've to disagree with it in some aspects. Soap colorants range from various kinds of Mica to dyes found ...
paracetamol's user avatar
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23 votes
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Why is manganese(II) coloured although the transition should be spin-forbidden?

Selection rules The intensity of the transition from a state $\mathrm{i}$ to a state $\mathrm{f}$ is governed by the transition dipole moment $\mu_{\mathrm{fi}}$ (strictly, it is proportional to $|\...
orthocresol's user avatar
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22 votes
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Explanation for why nickel turns green in hydrochloric acid

The question is really badly worded. For starters, let’s look at solutions of nickel(II): Figure 1: Nickel(II) solutions. From left to right: $\ce{[Ni(NH3)6]^2+}$, $\ce{[Ni(en)3]^2+}$, $\ce{[NiCl4]^2-...
Jan's user avatar
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21 votes
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What exact color does ozone gas have?

Due to Chappuis absorption, ozone does have a bluish color. To determine exactly what kind of blue it is, let's first look at the spectrum of absorption in the Chappuis band. The following plot was ...
Ruslan's user avatar
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18 votes
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Why/how is blood red? (colours of hemoglobin)

The $\ce{Fe}$-porphyrin complex is a vastly conjugated $\pi$-system, in which the oxidation state of the $\ce{Fe}$ plays a central role. The wavelength of light absorbed by hemoglobin exactly ...
ringo's user avatar
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17 votes

Soaps come in different colors, but why is soap lather always white?

You might have observed that large soap bubbles are transparent. This is because the color has been diluted to a great extent that it basically became transparent. Now, the foam is just a multitude ...
DHMO's user avatar
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17 votes
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Colour of platinum

In bulk metals, electrons in the conduction band are shared, creating a "sea" of reflective electrons. A nanoparticle, though, is so small that there is no conduction "band", just discrete levels ...
DrMoishe Pippik's user avatar
16 votes
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What gives milk its characteristic white color?

There is no "pigment" that makes milk white. According to Wikipedia: A pigment is a material that changes the color of reflected or transmitted light as the result of wavelength-selective ...
paracetamol's user avatar
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16 votes

Why is anhydrous copper(II) sulfate white while the pentahydrate is blue, even though both have one unpaired electron?

Let's compare the two compounds, here I plotted the $\ce{Cu(II)}$ centers of $\ce{CuSO4.5H2O}$ and $\ce{CuSO4}$ from their crystal structure data. As you can see, it changes from a $\ce{[Cu(H2O)4[SO4]...
Justanotherchemist's user avatar
13 votes
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Is chromium the shiniest metal?

You likely refer to remission, especially if you would collect spectroscopic data with an integration sphere at hand. More generally, you refer to reflectance, which depends on the material, the ...
Buttonwood's user avatar
13 votes
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Why does color of substances not disappear after some time?

If you are seriously interested in understanding why things are colored, there is a book called The Physics and Chemistry of Color: The Fifteen Causes of Color, by Kurt Nassau. It should be available ...
AChem's user avatar
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12 votes

Is it true that heavy water is not blue?

If you saw it during the 1990s online era, it might well have been reference links on my old website, from this article on physics misconceptions in grade school. I'd been doing some textbook-...
wbeaty's user avatar
  • 411
11 votes

Why are acids usually depicted in fiction as green?

Actually, I'd rather say the green-yellowish color is attributed to both toxic chemicals and radioactive waste in general and not only to the super acids. It might as well be that the corrosive acidic ...
andselisk's user avatar
  • 37.9k
11 votes

Why is manganese(II) coloured although the transition should be spin-forbidden?

To continue with the answer from @orthocresol. The breaking of formally ‘ forbidden’ transitions is very common indeed, possibly the best example is in the observation of phosphorescence from almost ...
porphyrin's user avatar
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11 votes
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Are complex ions thermochromic?

Indeed, this effect is observed in certain select cases. The effect of spin-spin cross over has been mentioned in this regard. There can be some other effects at play, namely: phase transitions, ...
getafix's user avatar
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11 votes
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Why is Prussian blue ‘blue’ in colour?

Prussian blue contains both $\ce{Fe(II)}$ and $\ce{Fe(III)}$. Mixed-valence compounds, such as the one in question, absorb certain wavelengths of visible light resulting due to the phenomenon of inter ...
getafix's user avatar
  • 8,495
11 votes

Anthracine blue composition

Springmühl indeed reported Anthracene Blue (orig. "Anthracenblau" (German)) from an intermediate with brutto-formula $\ce{C14H7O3}$. It seems like this method only worked well at a lab scale....
andselisk's user avatar
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10 votes
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What chemical properties that allow for colour exist in the dark?

The chemical property that creates colour is the ability to absorb light of a specific visible wavelength. There is more than one way to do this. Mostly colour is caused by the existence of ...
matt_black's user avatar
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10 votes

Why is F2 (fluorine) colourful despite being diamagnetic?

The colour of a molecule does not depend on the whether the molecule is diamagnetic or paramagnetic. The reason is that the colour is caused by absorption of a photon in the visible part of the ...
porphyrin's user avatar
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10 votes

Explanation for why nickel turns green in hydrochloric acid

Anhydrous nickel chloride is yellow. However most simple divalent salts of nickel are green. This should be good enough for high school. The question is poorly worded because it is ambiguous (...
AChem's user avatar
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9 votes
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Increasing Covalent character increases Colour intensity

In molecular orbital theory, as the covalent character increases the homo-lumo gap decreases, and the excitation happens more easily. Thus the colour intensity increases.
Harsh gupta's user avatar
9 votes
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Why lithium gives flame coloration?

I would love to find numbers, but alas, I have failed. If anyone can point me towards energy differences between the orbitals I am lacking, please feel free! There is no a priori physical reason why ...
Jan's user avatar
  • 68.2k
9 votes

Are complex ions thermochromic?

As correctly commented by @orthocresol, there are instances of thermochromicity for transition metal complexes, but it is rather seldom. It may occur provided the molecular orbitals of the complex ...
Buttonwood's user avatar
9 votes
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Can flames be colored black?

If black means that the flame does not emit light that is visible to the human eye then there is a certain chance that black flames might exist. Since hot flames emit black body radiation and the ...
aventurin's user avatar
  • 7,220
9 votes
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Chemical elements or compounds with yellowish white color

Aluminium(III) chloride - often described as white but samples is sometimes contaminated with iron(III) chloride giving it a light yellow color Antimony(V) oxide - pale yellow solid Bismuth(III) oxide ...
Nilay Ghosh's user avatar
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