Names | |
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Preferred IUPAC name
4-[Bis(4-hydroxyphenyl)methylidene]cyclohexa-2,5-dien-1-one | |
Other names
Aurin, corallin, p-rosolic acid, C.I. 43800
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Identifiers | |
3D model (JSmol)
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2055205 | |
ChEMBL | |
ChemSpider | |
ECHA InfoCard | 100.009.129 |
EC Number |
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PubChem CID
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UNII | |
CompTox Dashboard (EPA)
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Properties | |
C19H14O3 | |
Molar mass | 290.318 g·mol−1 |
Appearance | see text |
Density | 1.283 g/cm3 |
Melting point | 308 °C (586 °F; 581 K) (decomposes) |
Insoluble | |
UV-vis (λmax) | 482 nm[1] |
-161.4·10−6 cm3/mol | |
Hazards | |
GHS labelling: | |
[1] | |
Danger | |
H315, H319, H335[1] | |
P261, P305+P351+P338[1] | |
NFPA 704 (fire diamond) | |
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
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Aurin (C.I. 43800), sometimes named rosolic acid or corallin is an organic compound, forming yellowish or deep-red crystals with greenish metallic luster. It is practically insoluble in water, freely soluble in alcohol. It is soluble in strong acids to form yellow solution, or in aqueous alkalis to form carmine red solutions.
Aurin (pH indicator) | ||
below pH 5.0 | above pH 6.8 | |
5.0 | ⇌ | 6.8 |
Due to this behaviour it can be used as pH indicator with pH transition range 5.0 - 6.8. It is used as an intermediate in manufacturing of dyes.