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How to get a yellow precipitate with non-hazardous chemicals?

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jag93:
I am trying to find a chemical reaction that will give a yellow precipitate. I know about the "golden rain" reaction (potassium iodide + lead nitrate), but I would ideally like to find a reaction that doesn't require very hazardous/toxic chemicals (such as lead nitrate). Does anyone know of such a reaction? I am a scientist at a University, so can easily get just about any dry chemicals. Thanks.

wildfyr:
I found this list

8
Chromates, AgBr, As2S3, AgI, PbI2, CdS, PbCrO4(s), Hg2CO3(s), Ag3PO4(s), Bi(C6H3O3)(s), Cu(CN)2(s), Ag3AsO3(s), (NH3)3[As(Mo3O10)4](s), [SbI6]3-(aq),
Yellow

https://en.wikipedia.org/wiki/Qualitative_inorganic_analysis

Yellow seems to really like nasty metals like lead, mercury, and antimony. By far the least nasty and easiest to make of these I see is the silver ones.

Simple enough, just dissolve silver nitrate, and add the appropriate sodium salt! I bet silver phosphate will be the yellowest, I've made silver halides and they usually look black, but you should try them all!

Remember silver nitrate+light will stain skin (harmlessly).

chenbeier:
Maybe precipitate sulfur from Thiosulfate by adding acid. It is first white and change to yellow. Some sulfur dioxide will be released as well.

hollytara:
Does it have to be inorganic?

You can go all natural - take a substance with yellow coloring (turmeric works pretty well!) and steep it in 2-propanol or acetone.  The yellow curcuminoids go into the polar solvent.  If you drop this into a really nonpolar solvent like hexane, they will precipitate out as a yellow clumpy powder. 

Or - you can use a 2,4-dinitrophenylhydrazine reaction with an aldehyde or ketone (benzaldehyde is a good one) to make the very yellow orange 2,4-dinitrophenylhydrazone.  You can find procedures in almost any organic lab text.

chenbeier:
These are also Hazardous. Hydrazine and derivates are carcinogen. The solvents as well.

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