CAS number 504-15-4 YesY
PubChem 10436
ChemSpider 13839080 N
UNII 534PMB3438 N
Jmol-3D images Image 1
Molecular formula C7H8O2
Molar mass 124.13 g/mol (anhydr.)
Appearance Crystalline
Melting point

110.0-110.5 °C – 107 °C (anhydr.)

Boiling point

290 °C (289.5 °C)

Solubility in water Miscible
 N (verify) (what is: YesY/N?)
Except where noted otherwise, data are given for materials in their standard state (at 25 °C, 100 kPa)
Infobox references

Orcinol is a natural phenolic organic compound that occurs in many species of lichens[2] including Rocella tinctoria and Lecanora. It can be formed by fusing extract of aloes with potash.

It is used in the production of the dye orcein and as a reagent in some chemical tests for pentoses, such as Bial's Test. It may be synthesized from toluene; more interesting is its production when acetone dicarboxylic ester is condensed with the aid of sodium. It crystallizes in colorless prisms with one molecule of water, which redden on exposure to air. Ferric chloride gives a bluish-violet coloration with the aqueous solution. Unlike resorcinol it does not give a fluorescein with phthalic anhydride. Oxidation of the ammoniacal solution gives orcein, C28H24N2O7, the chief constituent of the natural dye archil. Homo-pyrocatechin is an isomer (CH1: OH: OH= 1 3 :4), found as its methyl ether (creosol) in beech-wood tar.


See also


  1. ^ Merck Index, 11th Edition, 6819.
  2. ^ Robiquet: „Essai analytique des lichens de l’orseille“, Annales de chimie et de physique, 1829, 42, p. 236–257.