Structure of 6-Nitroveratraldehyde (CAS NO.20357-25-9):

IUPAC Name: 4,5-dimethoxy-2-nitrobenzaldehyde 
Empirical Formula: C₉H₉NO₅
Molecular Weight: 211.1715 
EINECS: 243-762-1 
Index of Refraction: 1.571
Molar Refractivity: 52.9 cm³
Molar Volume: 160.9 cm³
Polarizability: 20.97×10^-24cm³
Surface Tension: 46.8 dyne/cm
Density: 1.312 g/cm³
Flash Point: 194.3 °C
Enthalpy of Vaporization: 64.03 kJ/mol 
Melting Point: 133.2-134.5 °C
Boiling Point: 390.8 °C at 760 mmHg
Vapour Pressure: 2.59E-06 mmHg at 25°C 
Sensitive: Air & Light Sensitive 
Physical Appearance: yellow fluffy powder
Product Categories: Aromatic Aldehydes & Derivatives (substituted);Benzaldehyde;Aldehydes;C9;Carbonyl Compounds 
Synonyms of 6-Nitroveratraldehyde (CAS NO.20357-25-9): 4,5-Dimethoxy-2-nitrobenzaldehyde ; 4,5-Dimethoxy-2-nitrobenzolcarbaldehyd ; Benzaldehyde, 4,5-dimethoxy-2-nitro- ; 2-nitro-4,5-bis(methyloxy)benzaldehyde ; 2-Nitro-4,5-dimethoxybenzaldehyde ; 3,4-Dimethoxy-6-nitrobenzaldehyde

Hazard Codes: Xi
Safety Statements: 24/25 
S24/25:Avoid contact with skin and eyes.
WGK Germany: 3
RTECS: GY8410000
HazardClass: IRRITANT

 6-Nitroveratraldehyde (CAS NO.20357-25-9) is hazardous,so the first aid measures should be known .Such as:
Skin: Get medical aid. Flush skin with plenty of water for at least 15 minutes while removing contaminated clothing and shoes.
Eyes: Flush eyes with plenty of water for at least 15 minutes, occasionally lifting the upper and lower eyelids.
Inhalation: Remove from exposure and move to fresh air immediately.
Ingestion:Do NOT induce vomiting. If conscious and alert, rinse mouth and drink 2-4 cupfuls of milk or water.
Another, Polymerization of the 6-Nitroveratraldehyde (CAS NO.20357-25-9)  is stable under normal temperature and pressure conditions,and you must not take it with strong oxidants.And also prevent it to broken down into hazardous decomposition products:irritating and toxic fumes and gases.