IUPAC Name: 4,5-Dichloro-2-phenylpyridazin-3-one
Synonyms: 4,5-Dichloro-2-phenyl-3(2H)-pyridazinone ; 2-Phenyl-4,5-dichloro-3-pyridazinone ; 3(2H)-Pridazinone, 4,5-dichloro-2-phenyl- ; 4,5-Dichloro-2-phenyl-2,3-dihydropyridazin-3-one ;  4,5-Dichloro-2-phenyl-2H-pyridazin-3-one
Product Categories: Pyridines, Pyrimidines, Purines and Pteredines;Building Blocks;Halogenated Heterocycles;Heterocyclic Building Blocks;Pyridazines;PyridazinesHeterocyclic Building Blocks
CAS NO: 1698-53-9
Molecular Formula: C₁₀H₆Cl₂N₂O
Molecular Weight: 241.07
Molecular Structure:
EINECS: 216-917-6
Mol File: 1698-53-9.mol
Index of Refraction: 1.641
Surface Tension: 50.6 dyne/cm
Density: 1.43 g/cm³
Flash Point: 139.4 °C
Melting point: 164-166 °C(lit.)
Enthalpy of Vaporization: 54.75 kJ/mol
Boiling Point: 307 °C at 760 mmHg
Vapour Pressure: 0.000746 mmHg at 25°C
Appearance: 4,5-Dichloro-2-phenyl-3(2h)-pyrid-azinone (CAS NO. 1698-53-9) is light beige crystalline powder .

S26: In case of contact with eyes, rinse immediately with plenty of water and seek medical advice. Moderately toxic by ingestion. A severe eye irritant. When heated to decomposition it emits very toxic fumes of Cl⁻ and NO_x.
Hazard Codes Xi
Risk Statements 36/37/38
R36/37/38: 4,5-Dichloro-2-phenyl-3(2h)-pyrid-azinone (CAS NO. 1698-53-9) is irritating to eyes, respiratory system and skin.
Safety Statements 26-37/39
S26: In case of contact with eyes, rinse immediately with plenty of water and seek medical advice.
S37/39:Wear suitable gloves and eye/face protection.
WGK Germany 2
RTECS UR6200000
Hazard Note Irritant 

General Information: As in any fire, wear a self-contained breathing apparatus in pressure-demand, MSHA/NIOSH (approved or equivalent), and full protective gear. During a fire, irritating and highly toxic gases may be generated by thermal decomposition or combustion.
Extinguishing Media: Use agent most appropriate to extinguish fire 
Handling: Wash thoroughly after handling. Remove contaminated clothing and wash before reuse. Avoid contact with eyes, skin, and clothing. Avoid ingestion and inhalation.
Storage: Store 4,5-Dichloro-2-phenyl-3(2h)-pyrid-azinone (CAS NO. 1698-53-9) in a cool, dry place. Keep container closed when not in use.