Chrysoine resorcinol
A synthetic azo dye once used in food and as a pH indicator
No single value: Chrysoine resorcinol is a material, and its colour varies. The background shows its family, orange.
Chrysoine resorcinol is a man-made azo dye that was previously added to foods, but is now banned for this use in Europe and the US. It is also known as Acid orange 6 and serves as a pH indicator, changing colour between pH 11 and 12.7, and is used in colour measurement.
- Synthetic azo dye once used in food
- Banned as a food additive in Europe (1977) and US (1988)
- Acts as a pH indicator between pH 11 and 12.7
- Absorption maximum at 387 nm
- Made by coupling sulfanilic acid and resorcinol
What colour is Chrysoine resorcinol?
Chrysoine resorcinol is a synthetic dye from the azo group, which means it contains nitrogen double bonds linking its chemical parts. It is also called Acid orange 6. The dye is orange in colour and can change shade depending on the conditions, especially pH. It is distinct for its use as a pH indicator, shifting colour between pH 11 and 12.7, and for its absorption maximum at 387 nanometres in colour measurement.
Where does Chrysoine resorcinol come from?
The name 'chrysoine resorcinol' comes from its chemical structure, which includes a resorcinol group. It is a synthetic compound, not found in nature. The dye was developed for use in foods and laboratory applications. Its use as a food additive was later banned in Europe in 1977 and in the United States in 1988.
How is Chrysoine resorcinol made?
Chrysoine resorcinol is made by a chemical reaction called azo coupling. In this process, sulfanilic acid and resorcinol are combined to form the dye. This method produces the orange-coloured compound in a laboratory setting, rather than from natural sources.
Where Chrysoine resorcinol is used
The dye was once used to colour foods, but this use is now prohibited in several regions. Today, chrysoine resorcinol is mainly used in laboratories. It serves as a pH indicator, changing colour in alkaline conditions, and is used in colourimetry, which is the measurement of colour.
Orange around the world
What the orange family means from country to country.
The lowest band of the flag is orange, often called apricot, after the national fruit. The constitution says it stands for the creative talent and hard work of the people.
Politics and protestNature and renewalPrideSource: Flag of ArmeniaThe flag is split corner to corner. The orange half stands for the Buddhist tradition, and the white dragon across the middle for purity.
Sacred and holySource: Flag of BhutanOn 30 September people wear orange shirts to remember the children sent to residential schools. Phyllis Webstad's new orange shirt was taken from her on her first day at one.
Mourning and deathPolitics and protestGriefSource: National Day for Truth and ReconciliationOrange is also the colour of the New Democratic Party. Its sweep of Quebec seats in the 2011 election was called the Orange Wave.
Politics and protestSource: New Democratic PartyThe flag shows the island in copper orange on white. The colour recalls copper, which was mined here in ancient times and may have taken its name from Cyprus.
Politics and protestNature and renewalSource: Flag of CyprusThe orange stripe of the flag stands for Protestants, the followers of William of Orange. In Northern Ireland the Orange Order still marches each 12 July in orange sashes.
Politics and protestSource: Orange OrderShades and relatives of Chrysoine resorcinol
Chrysoine resorcinol is also known as Acid orange 6. It belongs to the broader group of azo dyes, which come in a range of colours. Its colour can shift depending on the pH, but it is mainly recognised for its orange shade.
Questions people ask about Chrysoine resorcinol
What colour is chrysoine resorcinol?
Chrysoine resorcinol is an orange dye. Its colour can change depending on the pH, especially in alkaline conditions.
Where does the name chrysoine resorcinol come from?
The name refers to its chemical structure, which includes a resorcinol group. It is also called Acid orange 6.
What is chrysoine resorcinol used for?
It was once used as a food dye, but is now mainly used as a pH indicator and in colour measurement in laboratories.
Is chrysoine resorcinol still used in food?
No, it was banned as a food additive in Europe in 1977 and in the United States in 1988.
How is chrysoine resorcinol made?
It is synthesised by combining sulfanilic acid and resorcinol in a chemical reaction called azo coupling.
Good reading and sources
- Chrysoine resorcinol on WikipediaEncyclopedia
- More pictures on Wikimedia CommonsPictures
- Wikidata recordOpen data
The facts on this page come from the Wikipedia article "Chrysoine resorcinol", written by its contributors and used under the CC BY-SA 4.0 licence, and from its Wikidata record (CC0). Rang rewrote the text in its own words, with AI assistance, and compares every page with the article to make sure no passage is copied. It may be reused under the same CC BY-SA 4.0 licence with a link back.
It may contain mistakes. The swatch is an approximation: named colours are not fixed standards, and every screen shows them a little differently. If something is wrong, tell us. Last refreshed 2026-10-03.
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