Picrolonic Acid

3-Methyl-4-nitro-1-(4-nitrophenyl)-5-pyrazolone; C₁₀H₈N₄O₅ = 264.2 (550-74-3)

General reagent grade of commerce.

A yellow or brownish yellow, crystalline powder; melting point, about 116°.

Complies with the following test.

Sensitivity Dissolve 25 mg in 10 mL of warm water containing 0.1 mL of glacial acetic acid; to 1 mL of this solution add 1 mL of a 0.05% w/v solution of calcium chloride previously heated to 60°. A bulky precipitate is produced within 5 minutes.