Tetrafluoromethane, also known as carbon tetrafluoride, is the simplest fluorocarbon (CF4). It has a very high bonding strength due to the nature of the carbon–fluorine bond. It can also be classified as a haloalkane or halomethane. Because of the multiple carbon–fluorine bonds, and the highest electronegativity of fluorine, the carbon in tetrafluoromethane has a significant positive partial charge which strengthens and shortens the four carbon–fluorine bonds by providing additional ionic character. Tetrafluoromethane is a potent greenhouse gas.
Tetrafluoromethane is sometimes used as a low temperature refrigerant. It is used in electronics microfabrication alone or in combination with oxygen as a plasma etchant for silicon, silicon dioxide, and silicon nitride.
| Chemical formula | CF4 | Molecular weight | 88 |
|---|---|---|---|
| CAS No. | 75-73-0 | EINECS No. | 200-896-5 |
| Melting point | -184℃ | Boling point | -128.1℃ |
| solubility | Insoluble in water | Density | 1.96g/cm³（-184℃） |
| Appearance | A colorless, odorless, nonflammable, compressible gas | Application | used in plasma etching process for various integrated circuits, and used also as laser gas, refrigerant etc. |
| DOT ID Number | UN1982 | DOT/IMO SHIPPING NAME | Tetrafluoromethane, Compressed or Refrigerant Gas R14 |
| DOT Hazard Class | Class 2.2 | ||
| Item | Value, grade I | Value, grade II | Unit |
|---|---|---|---|
| Purity | ≥99.999 | ≥99.9997 | % |
| O2 | ≤1.0 | ≤0.5 | ppmv |
| N2 | ≤4.0 | ≤1.0 | ppmv |
| CO | ≤0.1 | ≤0.1 | ppmv |
| CO2 | ≤1.0 | ≤0.5 | ppmv |
| SF6 | ≤0.8 | ≤0.2 | ppmv |
| Other fluorocarbons | ≤1.0 | ≤0.5 | ppmv |
| H2O | ≤1.0 | ≤0.5 | ppmv |
| H2 | ≤1.0 | —— | ppmv |
| Acidity | ≤0.1 | ≤0.1 | ppmv |
| *other fluorocarbons refer to C2F6、C3F8 | |||
