IUPAC Name: 1-[(2,4-Dimethylphenyl)hydrazinylidene]naphthalen-2-one
Molecular Formula: C₁₈H₁₆N₂O 
Formula Weight: 276.36g/mol
EINECS: 221-490-4
Appearance: salmon pink powder
Density: 1.14g/cm³
Melting Point: 156-158 °C
Boiling point: 429.6 °C at 760 mmHg
Refractive index: 1.615 
Molar Refractivity: 84.44 cm³
Polarizability: 33.47 10^-24 cm³
Surface tension: 41.8 dyne/cm 
Enthalpy of Vaporization: 76.87 kJ/mol
Flash Point: 213.6 °C
Vapor Pressure: 1.03E-09 mmHg at 25°C
Solubility: not soluble in water
Classification Code: Mutation data; Tumor data
Stability: Explosive combination can occur with strong oxidizing agents, metal salts, peroxides and sulfides
 The molecular structure of Sudan II (CAS NO.3118-97-6) is .

 Sudan II (CAS NO.3118-97-6) is a lysochrome (fat-soluble dye) azo dye used for staining of triglycerides in frozen sections, and some protein bound lipids and lipoproteins on paraffin sections. In industry, it is used to color nonpolar substances like oils, fats, waxes, greases, various hydrocarbon products, and acrylic emulsions.

IARC Cancer Review: Group 3 IMEMDT    IARC Monographs on the Evaluation of Carcinogenic Risk of Chemicals to Man . 7 ,1987,p. 56.(World Health Organization, Internation Agency for Research on Cancer,Lyon, France.: ) (Single copies can be ordered from WHO Publications Centre U.S.A., 49 Sheridan Avenue, Albany, NY 12210) ; Animal Sufficient Evidence IMEMDT    IARC Monographs on the Evaluation of Carcinogenic Risk of Chemicals to Man . 8 ,1975,p. 233.(World Health Organization, Internation Agency for Research on Cancer,Lyon, France.: ) (Single copies can be ordered from WHO Publications Centre U.S.A., 49 Sheridan Avenue, Albany, NY 12210) . Reported in EPA TSCA Inventory. Community Right-To-Know List. EPA Genetic Toxicology Program.

Questionable carcinogen with experimental carcinogenic data. Mutation data reported. When heated to decomposition it emits toxic fumes of NO_x.
Hazard Symbols:  Xi
Risk Statements：36/37/38
R36/37/38: Irritating to eyes, respiratory system and skin 
Safety Statements：26-37/39
S37/39: Wear suitable gloves and eye/face protection 
S26: In case of contact with eyes, rinse immediately with plenty of water and seek medical advice

  Sudan II (CAS NO.3118-97-6), its Synonyms are C.I. Solvent Orange 7 ; Sudan red ; 1-((2,4-Dimethylphenyl)azo)-2-naphthalenol ; 1-(2,4-Xylylazo)-2-naphthol ; 1-(o-Xylylazo)-2-naphthol ; 1-Xylylazo-2-naphthol ; 2-Naphthalenol, 1-((2,4-dimethylphenyl)azo)- ; 2-Naphthol, 1-(2,4-xylylazo)- ; A F Red No. 5 ; A.F. Red No. 5 ; Waxakol vermilion ; Waxakol vermilion L . It is red to orange-brownish powder.