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Binding compound to gas to control colour in electromagnetic field ?


Erina
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Trapped Helium, Nitrogen, Neon and Krypton gasses visually react most unoformly when placed inside an electromagnetic induction field, but they all glow in their respective colours. In order to control the colour outputted a compound e.g. copper chloride can be placed at the discharge point.

Although Helium cannot bind to anything, Nitrogen can apparently bind to a boron-based molecule, so would it be possible to combine a gas with a compound to control the colour emitted when exposed to the magnetic field ?

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6 hours ago, Erina said:

Trapped Helium, Nitrogen, Neon and Krypton gasses visually react most unoformly when placed inside an electromagnetic induction field, but they all glow in their respective colours. In order to control the colour outputted a compound e.g. copper chloride can be placed at the discharge point.

Although Helium cannot bind to anything, Nitrogen can apparently bind to a boron-based molecule, so would it be possible to combine a gas with a compound to control the colour emitted when exposed to the magnetic field ?

I don't think this is quite right. Magnetism and induction play no part in the operation of a gas discharge tube, so far as I am aware, except to generate the high voltage needed to strike the discharge in the first place. It's simply an electrical discharge that ionises the gas, which then emits light of a characteristic colour as the electrons recombine with the ions. 

I am also unaware that CuCl2 is used to modify the colour. Can you provide a reference for this? 

Since the phenomenon is due to atomic emission, I'm not sure that sending a discharge through chemical compounds would do anything other than to excite the emission spectra of the constituent atoms.

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The emission spectra are changed slightly by a magnetic field.

https://en.wikipedia.org/wiki/Zeeman_effect
But the effect will be too small to see unless you have a tremendously strong magnetic field.

 

 

On 9/18/2021 at 8:19 AM, exchemist said:

I am also unaware that CuCl2 is used to modify the colour. Can you provide a reference for this? 

The commonest use of copper chloride in this way is in fireworks.
The colors of most modern fireworks involve a few metal chlorides, which fluoresce strongly in the visible wavelengths: Barium chloride produces green; strontium chloride produces red; and copper chloride produces blue.
https://cen.acs.org/articles/95/i27/s-fireworks-produces-those-colorful.html

But it's also used in lasers

https://www.repairfaq.org/sam/laserccb.htm

 

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39 minutes ago, John Cuthber said:

The emission spectra are changed slightly by a magnetic field.

https://en.wikipedia.org/wiki/Zeeman_effect
But the effect will be too small to see unless you have a tremendously strong magnetic field.

 

 

The commonest use of copper chloride in this way is in fireworks.
The colors of most modern fireworks involve a few metal chlorides, which fluoresce strongly in the visible wavelengths: Barium chloride produces green; strontium chloride produces red; and copper chloride produces blue.
https://cen.acs.org/articles/95/i27/s-fireworks-produces-those-colorful.html

But it's also used in lasers

https://www.repairfaq.org/sam/laserccb.htm

 

Right. But in gas discharge tubes? I doubt that CuCl2 is used, though if it were I assume it would be to produce a green colour.

Krypton glows yellowish-green, I know. (Perhaps that accounts for the rather sickly yellow-green of older French traffic lights.) But, looking this up, I see that many of today's so-called "neon" lighting tubes are in fact fluorescent, relying on a coating on the glass to produce the colour, rather than direct emission from the gas inside. What I am having difficulty tracking down is what fluorescent material is used to produce green. My first guess would be an organic dye. Any idea?  

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2 hours ago, exchemist said:

Right. But in gas discharge tubes? I doubt that CuCl2 is used,

They typically use CuCl.

 

2 hours ago, exchemist said:

What I am having difficulty tracking down is what fluorescent material is used to produce green. My first guess would be an organic dye. Any idea?  

Almost certainly not an organic dye. The tubes are typically coated on the inside- much like an ordinary fluorescent tube.

That's a rather aggressive environment.
These are more likely.

https://en.wikipedia.org/wiki/Phosphor#Standard_phosphor_types

though just painting a clear lacquer onto a white tube would work, as long as it was heat resistant enough.

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1 hour ago, John Cuthber said:

They typically use CuCl.

 

Almost certainly not an organic dye. The tubes are typically coated on the inside- much like an ordinary fluorescent tube.

That's a rather aggressive environment.
These are more likely.

https://en.wikipedia.org/wiki/Phosphor#Standard_phosphor_types

though just painting a clear lacquer onto a white tube would work, as long as it was heat resistant enough.

So they do use use copper salts. Interesting. Do you know how, I mean where one puts this in the tube?

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