An organic heterotetracyclic compound that is naphtho[2,3-f]quinoline-7,12-dione carrying two additional hydroxy groups at positions 5 and 6. Used as an acid-base indicator. Between pH 0.0 and pH 1.6 it changes from pink to yellow, and between pH 6.0 and pH 7.6 it changes from yellow to green.
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This entity has been manually annotated by the ChEBI Team.