Neal
Hazard to Others
Posts: 164
Registered: 24-12-2021
Location: Chicago, IL, USA.
Member Is Offline
|
|
Compounds that reflect more than 1 color?
Can we have a larger inorganic compound where 1 side of the compounds reflects the X light and another side reflects Y light?
Look at potassium permanganate, a deep violet. Isn't ammonium pretty colorless? Well then look at ammonium permanganate, still mostly violet, but more
dull-colored, more grayish. What could be a large cation that has a bright color?
So, if something reflects both red and blue light in a 50/50 ratio, that would appear magenta to us. I went to Wikipedia to search "magenta covalent"
"magenta ionic" and "reflects magenta" and didn't find any inorganic compounds on the 1st page, had a lot of plant pigments and proteins and such.
Therefore, we don't seem to have any inorganic compounds where 1 part reflects red and another part reflects blue.
I also like to know if anyone defines contradictions, like it's impossible for something to be X, and of Y color. And by Y color, I'm talking spectral
colors. The answer is yes to the extent you get really really specific. There recently was a thread on the purple acid, a liquid. Therefore, it might
be a contradiction for a liquid to be a base and purple at the same time...
Liquids don't tend to form combination reactions with other liquids, so. If they did, would be fun to find 1s that are colored.
|
|
|
Texium
|
Thread Moved
14-7-2025 at 08:25 |
Radiums Lab
Hazard to Others
Posts: 299
Registered: 18-3-2025
Location: India
Member Is Offline
Mood: Experiencing the elegance of science.
|
|
Can you elobarate it? Is the colour change angle related, then Styro pyro has a video related to it.
Water is dangerous if you don't know how to handle it, elemental fluorine (F₂) on the other hand is pretty tame if you know what you are doing.
|
|
|
Neal
Hazard to Others
Posts: 164
Registered: 24-12-2021
Location: Chicago, IL, USA.
Member Is Offline
|
|
So MnO4- is a very colorful anion. What might be a colorful polyatomic cation.
|
|
|
bnull
National Hazard
Posts: 993
Registered: 15-1-2024
Location: East Woods
Member Is Offline
Mood: Fecking annoyed
|
|
Let me see if I got it: you want substances whose cation is known for its, uh, X color and whose anion is Y colored. Like, say, copper(ii) is blue,
permanganate is violet, and copper(ii) permanganate is reddish.
Polyatomic inorganic cations are not as common as the anions. Those I remember are uranyl, vanadyl, hydroxylammonium, hydrazonium and ammonium.
Edit:What do you mean by
Quote: Originally posted by Neal  | | There recently was a thread on the purple acid, a liquid. Therefore, it might be a contradiction for a liquid to be a base and purple at the same
time... |
Why would it be a contradiction?
[Edited on 14-7-2025 by bnull]
|
|
|
Neal
Hazard to Others
Posts: 164
Registered: 24-12-2021
Location: Chicago, IL, USA.
Member Is Offline
|
|
| Quote: Originally posted by bnull | | Let me see if I got it: you want substances whose cation is known for its, uh, X color and whose anion is Y colored. Like, say, copper(ii) is blue,
permanganate is violet, and copper(ii) permanganate is reddish. |
Well that is certainly my 1st question, but I didn't want to extend this that all inorganic compounds are ionic.
| Quote: Originally posted by bnull | Edit:What do you mean by
| Quote: Originally posted by Neal | | There recently was a thread on the purple acid, a liquid. Therefore, it might be a contradiction for a liquid to be a base and purple at the same
time... |
Why would it be a contradiction? |
Hydroxide and hydride bases lack d-orbitals or π-systems for visible absorption. So they're typically colorless or white. But I imagine this could be
expanded to other colors that are contradictory as well.
Spectroscopically forbidden, chemically contradictory property pairs, etc.
For example, it's contradictory for something to be a strong base and a gas at the same time, as being a strong base requires having high electron
density. But for colors, I'm looking for "It's impossible for X to be of Y color" where Y are only spectral colors.
[Edited on 14-7-2025 by Neal]
|
|
|
DraconicAcid
International Hazard
Posts: 4504
Registered: 1-2-2013
Location: The tiniest college campus ever....
Member Is Offline
Mood: Semi-victorious.
|
|
[Cu(LL)2]2+, [Ni(LL)3]2+, [Co(LL)3]3+, where LL is a bidentate, neutral ligand such as ethylenediamine or bipy.
Please remember: "Filtrate" is not a verb.
Write up your lab reports the way your instructor wants them, not the way your ex-instructor wants them.
|
|
|
bnull
National Hazard
Posts: 993
Registered: 15-1-2024
Location: East Woods
Member Is Offline
Mood: Fecking annoyed
|
|
Right, change "cations" and "anions" to "fragments". You want substances that have a fragment (let's call it) A whose color is X, a fragment B whose
color is Y, and the substance AB formed by such fragments has another color that may or may not have a color directly related to X or Y or both X and
Y. That's actually pretty interesting. I suppose you are considering also the effect of solvents in these substances?
Did you try Google Scholar?
|
|
|
DraconicAcid
International Hazard
Posts: 4504
Registered: 1-2-2013
Location: The tiniest college campus ever....
Member Is Offline
Mood: Semi-victorious.
|
|
I believe you're looking at it incorrectly. A compound that contains two coloured ions isn't going to reflect two separate colours. Each ion is
going to absorb a certain set of wavelengths- this could be one absorption, two absorptions, or three absorptions for a regular transition metal
complex, depending on the number of d electrons and whether there is a charge-transfer band. What gets reflected or transmitted is *all the other
wavelengths*.
If you have more than one coloured ion in the mixture, then there will be *fewer* reflected/transmitted wavelengths, not more.
Please remember: "Filtrate" is not a verb.
Write up your lab reports the way your instructor wants them, not the way your ex-instructor wants them.
|
|
|
Neal
Hazard to Others
Posts: 164
Registered: 24-12-2021
Location: Chicago, IL, USA.
Member Is Offline
|
|
| Quote: Originally posted by DraconicAcid | I believe you're looking at it incorrectly. A compound that contains two coloured ions isn't going to reflect two separate colours. Each ion is
going to absorb a certain set of wavelengths- this could be one absorption, two absorptions, or three absorptions for a regular transition metal
complex, depending on the number of d electrons and whether there is a charge-transfer band. What gets reflected or transmitted is *all the other
wavelengths*.
If you have more than one coloured ion in the mixture, then there will be *fewer* reflected/transmitted wavelengths, not more. |
I don't get it. If you have X + Y -> XY, and X absorbs A and reflects B, Y absorbs C and reflects D, why would they now reflect less spectral
colors?
An exception to this, is if the new combined compound is basically like combined in a conjugated way, making it behave like 1 compound instead of 2,
but that's usually for organic compounds, which are rarely colorful.
|
|
|
DraconicAcid
International Hazard
Posts: 4504
Registered: 1-2-2013
Location: The tiniest college campus ever....
Member Is Offline
Mood: Semi-victorious.
|
|
Consider complex X, which absorbs light at 350 nm - 450 nm and 500 nm - 550 nm. This will transmit light from 450 nm - 500 nm and from 550 nm - 750
nm,
Add in complex Y, which absorbs light from 450 nm - 500 nm. Now you'll only get transmittance from 550 nm - 750 nm.
Please remember: "Filtrate" is not a verb.
Write up your lab reports the way your instructor wants them, not the way your ex-instructor wants them.
|
|
|
Neal
Hazard to Others
Posts: 164
Registered: 24-12-2021
Location: Chicago, IL, USA.
Member Is Offline
|
|
| Quote: Originally posted by DraconicAcid | Consider complex X, which absorbs light at 350 nm - 450 nm and 500 nm - 550 nm. This will transmit light from 450 nm - 500 nm and from 550 nm - 750
nm,
Add in complex Y, which absorbs light from 450 nm - 500 nm. Now you'll only get transmittance from 550 nm - 750 nm. |
The problem now is, although you added a variable of transmitted light, you removed reflected light. I think compounds that transmit light, also
reflect light?
There's this famous liquid, where Wikipedia says "The liquid is green by reflected light and red by transmitted light." That liquid is... Mn2O7.
I guess I could look into who else has reflectance and transmittance at different wavelengths, this is mostly for liquids right?
|
|
|
Sulaiman
International Hazard
Posts: 3942
Registered: 8-2-2015
Member Is Offline
|
|
when the sun is viewed through gold foil it looks green.
teflected light is of course 'gold' coloured.
if anyone is planning to make some Mn2O7
rather than adding sulphuric acid to a pile of permanganate
slowly, gently, add the permanganate to an excess of acid without stirring,
the clean green floating liquid can be transferred via a disposable pipette.
remember to use ppe, and not use glass - just in case.
If you stir the mixture, please report what colour liquid you get.
CAUTION : Hobby Chemist, not Professional or even Amateur
|
|
|
![[*]](images/xpblue/default_icon.gif){kind=icon}
