How to prepare Gold Chloride solution?

utsavgupta · Jun 27, 2022

I see that most salt print toner recipes make use of a 1% wv solution of Gold Chloride.

I was unable to find it ready made here in India. However I do have the option of getting 1gm of Gold Chloride in powder form.

Can we dissolve it in distilled water just like we prepare the silver nitrate solution, or does it need more work to prepare the solution?

Thanks,

Utsav

AgX · Jun 27, 2022

Gold(III) chloride seem to be typically prepared by passing chlorine gas over gold powder at 180 - 250°C.

At least I have not found any other way hinted at, starting from metallic gold
.
I very much doubt that you find this way attractive for amateur use. It sure is not economic. You better sell the gold you likely have in mind and at hand and buy from the earnings readymade Gold chloride.

aldus_manutius · Jun 27, 2022

AgX said:
Gold(III) chloride seem to be typically prepared by passing chlorine gas over gold powder at 180 - 250°C.

At least I have not found any other way hinted at, starting from metallic gold
.
I very much doubt that you find this way attractive for amateur use. It sure is not economic. You better sell the gold you likely have in mind and at hand and buy from the earnings readymade Gold chloride.

The OP asked about "Gold CHLORIDE powder", not metallic gold. Gold chloride is, in fact, highly soluble in water and ethanol.

AgX · Jun 27, 2022

Ooops...

It seems complete reading is benefitial... (I read "prepare" as synthesizing.)

revdoc · Jun 27, 2022

I've never handled the dry substance, but everything I've read says gold (iii) chloride is highly soluble in water. On that basis, I see no reason it can't be dissolved in distilled water like most other photographic chemicals.

However, gold (i) chloride isn't soluble in water, so it matters which one you get.

Another issue is that there are two hydrates of gold(iii) chloride, so you'll have to account for that when making your solution. It also decomposes when exposed to light, and it's caustic, so you'll have to be careful.

mshchem · Jun 27, 2022

Gold chloride is available in sealed glass vials. When you are ready to dissolve it, you make a small scratch with a file on the vial and crack it open. Use distilled water and a squeeze wash bottle rinse the orange crystals into a 100ml flask and dilute to volume. This will yield 100 ml of 1% w/w Gold chloride solution.

xkaes · Jun 27, 2022

mshchem said:
Gold chloride is available in sealed glass vials. When you are ready to dissolve it, you make a small scratch with a file on the vial and crack it open. Use distilled water and a squeeze wash bottle rinse the orange crystals into a 100ml flask and dilute to volume. This will yield 100 ml of 1% w/w Gold chloride solution.

This is exactly what I have used. It dissolves quickly I water. I have only seen it in glass vials marked GOLD CHLORIDE "crystals", not "powder" -- so what the OP is referring to might be different. The crystals are not cheap, and make 100ml of 1% solution, as mentioned.

markjwyatt · Jun 27, 2022

Stephen Anchell has a formula for gold toner in his first edition cookbook. It is called Gold Chloride Blue Toner. (#95)

SolA

Water 250 ml
Thiocarbimide 3.4g

SolB
Water 250 ml
Citric Acid 3.4 g

SolC
Water 250 ml
Gold Chloride 1.0 gm

Use 30 ml of each stock solution ad add 300 ml water. Tone well-fixed (plain hypo bath) and washed prints for 10-30 min (average 15 min, longer for dark prints). Agitate while toning. Treat with washing aid, and wash for about 1 hour. Treats 3 11x14" prints.

He has other Blue toners using gold chloride (#91, #94, #96), a gold protective solution (uses 1% gold solution), #92- also listed under blue toners.

He also has a Nelson Gold toner (brown tones, #97). There could be others.

None of the formulas are just gold chloride solution.

For gold chloride he says "Bright golden yellow crystalline compound". "Contains about 50% of gold." Nothing more specific than that.

AgX · Jun 27, 2022

xkaes said:
I have only seen it in glass vials marked GOLD CHLORIDE "crystals", not "powder" -- so what the OP is referring to might be different.

This US vendor describes it as "powder" and it looks that way too.

Gold (III) Chloride Powder, AuCl3 (CAS No. 13453-07-1)

Gold Chloride Powder is a common inorganic gold compound. Stanford Advanced Materials (SAM) is a trust-worthy supplier of the Gold(III) Chloride Powder.

www.samaterials.com

Any crystal can be made/ground that small that it is perceived as powder. Also hydratisation has effect.

mshchem · Jun 27, 2022

Back in the 20th century, I would buy ampules like this. 15 grains, it was found if I remember correctly, as anhydrous, or a tri-hydrate. I bought from Fisher and Mallinckrodt. The ampules I have are HAuCl3•3H2O. Old packaging 15 grains newer 1 gram. Kodak Blue Toner, available back in the day came with a small brown bottle with gold chloride in a liquid solution.

xkaes · Jun 27, 2022

The Mallinckrodt glass vials I have are also 15 grains (0.97 grams) "GOLD CHLORIDE GRANULAR" -- but the formula is AuCl * HCl * 4H2O.

I'd check the formula for any "powder". It might just be desiccated

How to prepare Gold Chloride solution?

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