# Chlorine: Characteristics

Why chlorine moves as a pressurised liquid

Source page: https://www.materialinsights.org/chemicals/chlorine/characteristics/

What this tab covers The physical and chemical properties that set its grade, price and uses, with the commercial grades and the standards that define them.

Chlorine is a yellow-green gas that liquefies at minus 34 C or under about 7 bar at room temperature, which is why it moves as a pressurised liquid. Moisture makes it very corrosive, so it is dried before compression. Purity matters for water treatment and for catalysts in downstream units.

#### Properties that matter commercially

| Property | Value / specification | Why it matters | Source |
|---|---|---|---|
| **Purity** | liquid chlorine at least 99.5% Cl2 (IS 646) | water treatment and food uses require low impurities | BIS IS 646 |
| **Moisture** | below about 50 ppm (indicative) | wet chlorine corrodes steel | indicative |
| **Nitrogen trichloride** | kept at ppm levels | NCl3 is explosive and concentrates in liquid chlorine | Euro Chlor safety guidance (indicative) |
| **Boiling point and vapour pressure** | minus 34 C; about 6.8 bar at 20 C | sets container design | standard property |

#### Commercial grades

- Liquid chlorine in tonners and cylinders (water treatment, IS 646)
- Pipeline gaseous chlorine (captive)
- Electronic-grade chlorine for semiconductor etching (high purity)

## Other sections

- [Summary](https://www.materialinsights.org/chemicals/chlorine/index.md)
- [Overview](https://www.materialinsights.org/chemicals/chlorine/overview/index.md)
- [Correlation](https://www.materialinsights.org/chemicals/chlorine/correlation/index.md)
- [Production route](https://www.materialinsights.org/chemicals/chlorine/routes/index.md)
- [Production](https://www.materialinsights.org/chemicals/chlorine/production/index.md)
- [Feedstocks](https://www.materialinsights.org/chemicals/chlorine/feedstocks/index.md)
- [Cycles](https://www.materialinsights.org/chemicals/chlorine/cycles/index.md)
- [Trading](https://www.materialinsights.org/chemicals/chlorine/trading/index.md)
- [Movement](https://www.materialinsights.org/chemicals/chlorine/movement/index.md)
- [Regulation](https://www.materialinsights.org/chemicals/chlorine/regulation/index.md)
- [Emissions](https://www.materialinsights.org/chemicals/chlorine/emissions/index.md)
- [Relationships](https://www.materialinsights.org/chemicals/chlorine/links/index.md)