CAS 598-58-3: Nitrous Acid (HNO2)

Identity

CAS Number598-58-3
Molecular FormulaHNO2
IUPAC Namenitrous acid
Molecular Weight47.01 g/mol
SMILESON=O
Synonymsdinitrogen dioxide, HNO2, nitrous acid

2D Structure

Physical Properties

Density1.45 g/mL at 25°C
Boiling PointNone°C
Melting PointNone°C
Flash PointNone°C
Vapor PressureNone kPa at 20°C
Refractive IndexnD = None
Dielectric Constantε = None

Safety & GHS Classification

GHS03GHS05

Storage: Exists only in solution — cannot be isolated. Prepare fresh as needed. Unstable, decomposes to NO and NO2. Use in fume hood with acid-resistant PPE.

Material Compatibility Matrix

Plastics

MaterialRating
PTFEExcellent
PVCGood
PEGood
PPGood
PEEKExcellent
PVDFGood

Rubbers

MaterialRating
VitonGood
NBRSevere Effect
EPDMFair
SiliconeFair
FKMGood

Metals

MaterialRating
Stainless 316Fair
AluminumPoor
CopperPoor
BrassPoor

Applications

External References: PubChem

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