Gold · Au

Gold salts

Nearly all gold chemistry begins with the tetrachloroaurate(III) ion. Dissolve gold in aqua regia, evaporate with hydrochloric acid, and you have chloroauric acid; neutralise it with sodium or potassium chloride and you have the sodium and potassium salts. From these three come colloidal gold and gold nanoparticles of every size and shape, the supported gold catalysts that oxidise carbon monoxide at room temperature, the gold(I) phosphine and carbene complexes used in homogeneous catalysis, immersion and electroless gold plating, immunogold reagents for microscopy and lateral-flow tests, and gold(III) complexes studied as anticancer agents.

3 compoundsAu spot €118.27/g

Prices track live precious-metal spot rates. Price updated 21 Oct 2026, 18:15 (Dublin time). Prices are locked when an order or quote is created.

Compound	Formula	CAS	Au content	Pack sizes
Gold(III) chloride trihydrate	HAuCl₄·3H₂O	16961-25-4	50%	1 g, 5 g, 25 g
Sodium tetrachloroaurate(III) dihydrate	NaAuCl₄·2H₂O	13874-02-7	49.5%	1 g, 5 g, 25 g
Potassium tetrachloroaurate(III)	KAuCl₄	13682-61-6	52.1%	1 g, 5 g, 25 g

Gold50% Au

Gold(III) chloride trihydrate

HAuCl₄·3H₂O · CAS 16961-25-4

Chloroauric acid trihydrate is the workhorse gold precursor for colloidal gold and gold nanoparticle synthesis (Turkevich, Brust–Schiffrin, seeded growth), homogeneous gold catalysis, electroless and electrolytic gold plating, immunogold labelling for electron microscopy, ruby glass and Purple of Cassius, and gold-based pharmaceuticals research. Each lot is assayed for gold content and supplied with a certificate of analysis.

Grade: ≥99.9% (metals basis); Au ≈ 50%
Pack sizes: 1 g, 5 g, 25 g

from €114.00 excl. VAT

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Gold49.5% Au

Sodium tetrachloroaurate(III) dihydrate

NaAuCl₄·2H₂O · CAS 13874-02-7

Sodium tetrachloroaurate(III) dihydrate is a water-soluble, orange-yellow gold(III) salt that serves as a less acidic, easier-to-handle alternative to chloroauric acid. It is a standard precursor for gold nanoparticles and colloids, for supported gold catalysts made by deposition–precipitation (for example Au/TiO2), for homogeneous gold(III) catalysis, for electroless and immersion gold plating baths, and for gold coordination compounds. Approximately 49.5% gold by mass; gold content is assayed on every lot.

Grade: ≥99.9% (metals basis); Au ≈ 49.5%
Pack sizes: 1 g, 5 g, 25 g

from €113.00 excl. VAT

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Gold52.1% Au

Potassium tetrachloroaurate(III)

KAuCl₄ · CAS 13682-61-6

Potassium tetrachloroaurate(III) is a yellow to orange crystalline gold(III) salt, soluble in water and alcohols, used as a precursor for gold nanoparticles and thin films, for supported and homogeneous gold catalysts, in gold electroplating and decorative gilding formulations, and for the synthesis of gold(III) and gold(I) complexes. Approximately 52% gold by mass; supplied with a lot-specific gold assay and certificate of analysis.

Grade: ≥99.9% (metals basis); Au ≈ 52%
Pack sizes: 1 g, 5 g, 25 g

from €117.50 excl. VAT

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About our gold salts

We make all three in Dublin from gold refined by Liffey Metals, assay every lot for gold by weight, and print the result on the certificate of analysis. That assay matters more for gold salts than for most products: chloroauric acid is deliquescent and the commercial trihydrate is really a range of hydrates, so the gold content of a bottle can differ by a few percent from the formula value. Our prices are calculated from the live gold spot price and the nominal gold content, and the certificate tells you exactly what you received.

Choosing between the three is a question of handling rather than chemistry. Chloroauric acid is the most soluble and the one named in almost every published procedure, but it must be weighed quickly or dissolved as a whole pack, and its solutions are strongly acidic. Sodium tetrachloroaurate dihydrate is only mildly hygroscopic, gives near-neutral solutions and is the better choice for deposition–precipitation catalyst preparation and for biological conjugation. Potassium tetrachloroaurate is the most stable in storage and has the highest gold fraction, at the cost of lower solubility; it is the usual starting material for isolated gold complexes.

At roughly 50% gold by mass, these salts are mostly metal, which is why we price them to the spot and sell them in 1 g and 5 g packs as well as larger sizes. Chloroauric acid ships as a corrosive (UN3260, Class 8); the sodium and potassium salts are not regulated for transport. For a worked example of what to do with them, read our guide to synthesising gold nanoparticles with chloroauric acid, which covers citrate, Brust–Schiffrin and seeded nanorod methods with quantities.

Which gold compound do I need?

Chloroauric acid trihydrate: the literature standard: nanoparticles, Au/TiO₂ and Au/C catalysts, plating, immunogold. Deliquescent; dissolve whole packs.
Sodium tetrachloroaurate dihydrate: easy to weigh, near-neutral solutions: deposition–precipitation catalysts, bioconjugation, pH-sensitive syntheses.
Potassium tetrachloroaurate: most stable in storage, 52% gold: synthesis of gold(I) and gold(III) complexes, gold standards.

For research and industrial use only. Not for human, veterinary, food or cosmetic use. Need a pack size, grade or gold compound that is not listed? Request a quote and we will come back within one working day.