Croconate blue
A synthetic blue dye made from croconic acid and malononitrile
No single value: Croconate blue is a material, and its colour varies. The background shows its family, blue.
Croconate blue is a synthetic dye and chemical anion that appears deep blue in water. It is made by modifying croconic acid with dicyanomethylene groups and is known for its intense blue colour in solution and weak semiconducting properties.
- Deep blue in water, red in acetone or ethanol
- First synthesised in 1978 by A. Fatiadi
- Made from croconic acid and malononitrile
- Weak semiconductor at room temperature
What colour is Croconate blue?
Croconate blue is a synthetic blue dye and chemical compound. In water, it gives a deep blue colour, while in acetone or ethanol it appears red. The dye is based on a modified croconate structure, where three oxygen atoms are replaced by dicyanomethylene groups. Its salts, such as the dipotassium form, are known for their intense blue solutions and weak semiconducting behaviour.
Where does Croconate blue come from?
The compound was first synthesised in 1978 by A. Fatiadi. It is produced by reacting croconic acid with malononitrile in water at high temperatures. The name 'croconate blue' refers to its blue colour in water and its chemical relationship to croconic acid, a compound known for its colourful derivatives.
How is Croconate blue made?
Croconate blue is made by heating croconic acid with malononitrile in water at 80–90 °C. The resulting acid form can be converted to its dipotassium salt using potassium methoxide. The dye can also form salts with other cations, such as tetramethylammonium. Its blue colour is most intense in water, and it can slowly convert to other related compounds under certain conditions.
Blue around the world
What the blue family means from country to country.
Lapis lazuli has been mined in the mountains of Badakhshan for more than six thousand years. Ground to powder it gave ultramarine, the costliest blue in European painting.
Royalty and powerSacred and holyAweSource: Lapis lazuliThe chadari is a full-length covering for women with a mesh panel over the eyes. In Kabul and the north it is most often a light blue.
Protection and healingSource: BurqaThe blue band of the flag stands for the wish of the Armenian people to live under peaceful skies. The red above it is for the highlands and the struggle to survive.
Politics and protestHopeSource: Flag of ArmeniaThe flag is sky blue, white and sky blue, created by Manuel Belgrano in 1812. National teams are called the Albiceleste, the white and sky blue.
Politics and protestPrideSource: Flag of ArgentinaBoca Juniors play in blue and gold. The club's story is that in 1907 it took the colours of the flag of the next ship into port, which was Swedish.
Festival and celebrationPrideSource: Boca JuniorsTo be true blue is to be honestly and loyally Australian. The phrase is older than the country, but Australians have made it their own.
Politics and protestTrustSource: True Blue (John Williamson song)Shades and relatives of Croconate blue
Croconate blue is related to other dyes such as croconate violet and 2-(dicyanomethylene)croconate. It can change colour depending on the solvent, appearing red in acetone or ethanol and deep blue in water. Extended heating can produce a deep green polymer, and it can convert to croconate violet under basic conditions.
Questions people ask about Croconate blue
What colour is croconate blue?
Croconate blue appears deep blue in water. In acetone or ethanol, it turns red, and it can also form green-blue crystals depending on the salt and conditions.
Where does the name croconate blue come from?
The name comes from its chemical relationship to croconic acid and its blue colour in water. The dye is a modified form of the croconate anion.
How is croconate blue made?
It is made by heating croconic acid with malononitrile in water at 80–90 °C, then converting the product to its salt form using potassium methoxide or other reagents.
When was croconate blue first synthesised?
Croconate blue was first synthesised and described in 1978 by A. Fatiadi.
Good reading and sources
The facts on this page come from the Wikipedia article "Croconate blue", written by its contributors and used under the CC BY-SA 4.0 licence, and from its Wikidata record (CC0). EveryRang 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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