October 17, 2021, 09:47:28 PM
Forum Rules: Read This Before Posting


Topic: Photoluminecence in Cu(II) aq. with black light  (Read 193 times)

0 Members and 1 Guest are viewing this topic.

Offline quizzicalDude

  • Very New Member
  • *
  • Posts: 2
  • Mole Snacks: +0/-0
Photoluminecence in Cu(II) aq. with black light
« on: October 10, 2021, 05:38:31 PM »
Hi there!
I have a problem with luminescese in of Cu(II) in aq. solution.
A little bit of background.
I am not a chemist, never done chemistry professionally and the last time I had a chemistry class was when I studied Biology some years back.
This is for some self-made presents I want to hand out around Christmas.
I want to make some lamps akin to the self-made Nuka Cola bottles.
While I like the blue glow, quinine is a restricted substance as it is poisonous in larger quantities.
That and the fact that tonic water contains sugar, makes it an unsuitable substance to use.
After having done some reading, I found that copper provides a nice green glow (at least that is what the Balmer-Rydberg equation says), I would like to replicate.
My plan was to suspend copper in water, solidify the water using epoxy and mount a black light over the epoxy substrate leading to a nice ambient green glow.

So I bought some copper wire(not pure copper, I assume some iron to be in there as well, but copper will be the first to go), a cell-phone charger and a black light for testing.
Prepared the charger, stripped the copper wire and hung them, without them touching each other, on the opposite wires of the charger, in slightly salted(NaCL) water.
I get green foam alright (so Cu(II) is being created), but it is not reacting to the black light as expected.
Is the concentration to weak, too much water, is the black light too weak?
I assume I am missing something very fundamental here and I do not know of where to look specifically.
I might find it but most likely I will not as the body of knowledge regarding chemistry, especially phy. chemistry, which I never took to, is vast.
What would be worse would be to find s.th. that works as expected but is dangerous to handle, either by the recipient or me, so safety is paramount.
e.g. mixing vinegar and copper is a big no no.
I tend to try to work out the formula and looking up properties of products(transitional or final) of the compounds involved and only attempt it when I am successful and satisfied with my reading(safe to handle, easy to dispose of, etc.)


So, do you guys happen to have an idea of what I am doing wrong or can point me into a general direction of where I might find a safe solution.
Cheers
« Last Edit: October 10, 2021, 06:05:45 PM by quizzicalDude »

Offline Corribus

  • Chemist
  • Sr. Member
  • *
  • Posts: 3184
  • Mole Snacks: +485/-22
  • Gender: Male
  • A lover of spectroscopy and chocolate.
Re: Photoluminecence in Cu(II) aq. with black light
« Reply #1 on: October 10, 2021, 10:02:34 PM »
Not really sure what made you think copper ions were fluorescent because of the Rydberg formula...but it isnt the case.

Tonic water is probably still your best bet for something cheap that glows under a black light. Why is the sugar a problem. Can you use sugar free tonic water?
What men are poets who can speak of Jupiter if he were like a man, but if he is an immense spinning sphere of methane and ammonia must be silent?  - Richard P. Feynman

Offline quizzicalDude

  • Very New Member
  • *
  • Posts: 2
  • Mole Snacks: +0/-0
Re: Photoluminecence in Cu(II) aq. with black light
« Reply #2 on: October 11, 2021, 12:53:43 PM »
Hi Corribus,

Thanks for the reply.
Isn't the Rydberg formula used to determin the wavelength of light that is emitted when an electron is moving up and then down the orbital of an atom after being enticed? And according to that formula,unless I have made a mistake, copper should emit green light.

I will look into getting hold of some sugar free tonic water(didn't occure to me).

That being said, how would I go about determining the fluorescence of a chemical compound then, or put differently:
How would you go about it?

Offline Corribus

  • Chemist
  • Sr. Member
  • *
  • Posts: 3184
  • Mole Snacks: +485/-22
  • Gender: Male
  • A lover of spectroscopy and chocolate.
Re: Photoluminecence in Cu(II) aq. with black light
« Reply #3 on: October 11, 2021, 01:56:30 PM »
The Rydberg formula is only really relevant to hydrogenic systems, that is, ones in which there is only a single electron. Moreover, just because something fluoresces, this doesn't mean it fluoresces intensely. In point of fact, everything is technically fluorescent to some degree. But very few molecules fluoresce strong enough to see by eye. And even fewer do so in water.

There aren't too many common, water-dispersible substances that will fluorescence strongly under black light to get the Nuka-Cola effect you're looking for (love the idea tho - I'm a huge Fallout fan as well). Antifreeze often contains fluorescein dye that would work, but it's green not blue. Quinine, as you've noted, is readily available in tonic water, and it does fluoresce strongly a nice deep blue. Probably your easiest bet. Even better would be one of a number of blue laser dyes, like perylene or coumarin-1 (or some other in the coumarin family). But they may be harder to find for your typical consumer (I looked on amazon and didn't see any available) and would need a solvent other than water (alcohol, e.g.). If you're giving these as gifts, that could be a problem.
What men are poets who can speak of Jupiter if he were like a man, but if he is an immense spinning sphere of methane and ammonia must be silent?  - Richard P. Feynman

Sponsored Links