1,1-Difluoroethylene
[CAS 75-38-7]

Identification

• Classification: Chemical reagent >> Organic reagent >> Olefins (cyclic and non-cyclic)
• Name: 1,1-Difluoroethylene
• Molecular Formula: C₂H₂F₂
• Molecular Weight: 64.03
• CAS Registry Number: 75-38-7
• EC Number: 200-867-7
• SMILES: C=C(F)F

Properties

• Density: 1.0±0.1 g/cm³ Calc.^*
• Melting point: -143.9 °C (Expl.)
• Boiling point: -85.7±8.0 °C 760 mmHg (Calc.)^*, -85.6 °C (Expl.)
• Flash point: -90.9±6.3 °C (Calc.)^*
• Solubility: water: insoluble (Expl.)
• Index of refraction: 1.265 (Calc.)^*

^* Calculated using Advanced Chemistry Development (ACD/Labs) Software.

Safety Data

• Hazard Symbols: GHS02;GHS04;GHS08 DangerGHS02;GHS02
• Risk Statements: H220-H230-H280-H340-H350
• Safety Statements: P203-P210-P222-P280-P318-P337-P377-P381-P403-P405-P410+P403-P501

Hazard Classification

Hazard	Class	Category Code	Hazard Statement
Gases under pressure (liquid)	Press. Gas (Liq.)		H280
Flammable gases	Flam. Gas	1	H220
Germ cell mutagenicity	Muta.	1B	H340
Carcinogenicity	Carc.	1A	H350
Gases under pressure (compressed)	Press. Gas (Comp.)		H280
Flammable liquids	Flam. Liq.	1	H224

• Transport Information: UN 1959

chemBlink Chemical Story

1,1-Difluoroethylene, CAS 75-38-7, is better known as vinylidene fluoride (VDF), with the formula CH2=CF2. PubChem describes it as a colorless flammable gas and identifies it as both an organofluorine compound and an olefin. Its importance comes overwhelmingly from the carbon-carbon double bond: VDF is a monomer designed to be converted into fluorinated polymers.

Free-radical polymerization of VDF gives poly(vinylidene fluoride), PVDF, whose repeating unit is -CH2-CF2-. PVDF combines chemical resistance, weatherability and thermal stability with properties unusual among commodity polymers. Its chains contain strongly polar C-F bonds, and certain crystalline phases are piezoelectric and pyroelectric. Mechanical deformation can therefore generate electrical polarization, while an applied electric field can produce mechanical response.

These properties created applications far beyond ordinary plastic fabrication. PVDF is used in chemical-resistant piping and coatings, wire and cable insulation, membranes, sensors and electroactive films. In lithium-ion batteries, PVDF is widely used as an electrode binder because it combines electrochemical stability with adhesion and processability in common electrode-manufacturing systems.

VDF is also copolymerized with other fluorinated monomers. Copolymers with hexafluoropropylene are important in fluoropolymer and battery-related applications, while copolymers containing trifluoroethylene can display strong ferroelectric behavior. Thus the same small gaseous monomer provides access to a family of materials whose properties can be tuned by comonomer selection and crystalline structure.

The monomer itself requires careful industrial handling because it is a compressed, flammable gas. Its chemical story is therefore mainly a story of transformation: CH2=CF2 is not valued as a finished object, but because polymerization converts its double bond into long chains that preserve fluorine's chemical robustness while creating useful mechanical, electrical and electrochemical properties.

References:
1. PubChem, Vinylidene fluoride, CID 6369, CAS 75-38-7.
2. Lovinger AJ. Ferroelectric polymers. Science. 1983;220:1115-1121.
3. Martins P, Lopes AC, Lanceros-Mendez S. Electroactive phases of poly(vinylidene fluoride). Prog Polym Sci. 2014;39:683-706.

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