Editing Noble gas (section)

==Discharge color==

{| class="wikitable" style="text-align:center;margin:1em auto"
|+ Colors and spectra (bottom row) of electric discharge in noble gases; only the second row represents pure gases.
| width="20%"|[[File:Helium-glow.jpg|alt=Glass tube shining violet light with a wire wound over it|120px]]
| width="20%"|[[File:Neon-glow.jpg|alt=Glass tube shining orange light with a wire wound over it|120px]]
| width="20%"|[[File:Argon-glow.jpg|alt=Glass tube shining purple light with a wire wound over it|120px]]
| width="20%"|[[File:Krypton-glow.jpg|alt=Glass tube shining white light with a wire wound over it|120px]]
| width="20%"|[[File:Xenon-glow.jpg|alt=Glass tube shining blue light with a wire wound over it|120px]]
|-
| width="20%"|[[File:Helium discharge tube.jpg|alt=Glass tube shining light red|120px]]
| width="20%"|[[File:Neon discharge tube.jpg|alt=Glass tube shining reddish-orange|120px]]
| width="20%"|[[File:Argon discharge tube.jpg|alt=Glass tube shining purple|120px]]
| width="20%"|[[File:Krypton discharge tube.jpg|alt=Glass tube shining bluish-white|120px]]
| width="20%"|[[File:Xenon discharge tube.jpg|alt=Glass tube shining bluish-violet|120px]]
|-
| width="20%"|[[File:HeTube.jpg|alt=Illuminated light red gas discharge tubes shaped as letters H and e|120px]]
| width="20%"|[[File:NeTube.jpg|alt=Illuminated orange gas discharge tubes shaped as letters N and e|120px]]
| width="20%"|[[File:ArTube.jpg|alt=Illuminated light blue gas discharge tubes shaped as letters A and r|120px]]
| width="20%"|[[File:KrTube.jpg|alt=Illuminated white gas discharge tubes shaped as letters K and r|120px]]
| width="20%"|[[File:XeTube.jpg|alt=Illuminated violet gas discharge tubes shaped as letters X and e|120px]]
|-
| width="20%"|[[File:Helium spectra.jpg|alt=Helium line spectrum|120px]]
| width="20%"|[[File:Neon spectra.jpg|alt=Neon line spectrum|120px]]
| width="20%"|[[File:Argon Spectrum.png|alt=Argon line spectrum|120px]]
| width="20%"|[[File:Krypton Spectrum.jpg|alt=Krypton line spectrum|120px]]
| width="20%"|[[File:Xenon Spectrum.jpg|alt=Xenon line spectrum|120px]]
|-
|[[Helium]]
|[[Neon]]
|[[Argon]]
|[[Krypton]]
|[[Xenon]]
|}

The color of gas discharge emission depends on several factors, including the following:<ref>{{cite book|pages=383–384|url=https://books.google.com/books?id=AEFPNfghI3QC&pg=PA383|title=Scientific photography and applied imaging|author=Ray, Sidney F.|publisher=Focal Press|year=1999|isbn=0-240-51323-1}}</ref>

* discharge parameters (local value of [[current density]] and [[electric field]], temperature, etc. – note the color variation along the discharge in the top row);
* gas purity (even small fraction of certain gases can affect color);
* material of the discharge tube envelope – note suppression of the UV and blue components in the bottom-row tubes made of thick household glass.