Chemistry Alchemist - 13-7-2012 at 09:01
I was walking around in K-mart today and looked in the paint section and noticed on the price tag it said Cadmium Red, I looked it up on the wiki and
it said Cadmium Sulfide is used to make a Yellow Pigment, but when Selenium is added to the compound the pigment goes from Yellow to Red, would CdSe
be the compound that makes up this paint? If so, how would i extract Both of the compounds and separate them?
elementcollector1 - 13-7-2012 at 09:42
Likely not. Cadmium selenide is red, true, but the synthesis procedure describes some very controlled conditions and has no references to use in
paints.
Additionally, if you want metallic cadmium, find an old NiCd battery. There's a sheet of cadmium in there.
[Edited on 13-7-2012 by elementcollector1]
barley81 - 13-7-2012 at 09:50
It is true. Cadmium red is an artist's pigment. It is a mixture of cadmium sulfide and selenide:
http://www.webexhibits.org/pigments/indiv/overview/cdyellowr...
If you want cadmium compounds, it is easier to buy cadmium metal from eBay than to use cadmium red. Conversion of cadmium red to other cadmium
compounds involves the release of very toxic gases (H<sub>2</sub>S, H<sub>2</sub>Se - very smelly!). Eextracting the fine
particles of pigment from a thick paint containing emulsifiers/other stuff is probably difficult. I don't think it's worth it.
Chemistry Alchemist - 13-7-2012 at 09:52
Cadmium pigments are a class of pigments that have cadmium as one of the chemical components. They are highly toxic and can produce cadmium poisoning.
Most of cadmium produced worldwide is used in the production of nickel-cadmium batteries, but about half the remaining consumption, which is about
2,000 tons annually, is used to produce colored cadmium pigments. The principal pigments are a family of yellow/orange/red cadmium sulfides and
sulfoselenides. Cadmium yellow is cadmium sulfide (CdS); by adding increasing amounts of selenium, colors ranging from orange to nearly black (the
color of cadmium selenide) can be produced. Cadmium yellow is sometimes mixed with viridian to give a bright, pale green mixture called cadmium green.
http://en.wikipedia.org/wiki/Cadmium_pigments
unionised - 13-7-2012 at 12:17
"Cadmium red" has two meanings. One is the CdS/CdSe pigment, the other is "any paint that's roughly the same colour as the real thing".
I don't know about Australia but you probably wouldn't be permitted to sell a real cadmium-based paint in a DIY store here in the UK.