What Is Chlorine Dioxide?

The history of ClO₂

Chlorine Dioxide (ClO₂) has become one of the most effective and reliable solutions for disinfection and biocidal applications across a wide range of industries. While its popularity has surged in recent years thanks to lower chemical costs and advanced generation methods, the core chemistry behind ClO₂ is well established and widely trusted.

Below we explore what Chlorine Dioxide is, its key properties, and how it has developed into a cornerstone of modern water treatment and sanitisation.

ClO₂ Fact File  

What is Chlorine Dioxide?
Chlorine Dioxide is a small, highly reactive molecule made up of one chlorine atom and two oxygen atoms. Abbreviated as ClO₂, it acts as a powerful oxidising agent, making it highly effective as a disinfectant.

Key Properties

• Molecular weight: 67.45

• State at room temperature: Gas

• Melting point: –59 °C

• Boiling point: 11 °C

• Appearance: Yellow‑green in colour with a chlorine‑like odour

• Density: Denser than air

• Solubility: Water soluble up to 2,500 ppm at standard temperature and pressure

• Stability: Decomposes under UV light, high temperatures (>70 °C), or high alkalinity (>pH 12)

• Safety note: Explosive in air at concentrations above 10%. For this reason, it is typically generated in situ as an aqueous solution at <0.2%.

Application Methods
While some pre‑mixed solutions are available at concentrations of ~0.6%, these are hazardous and costly to transport. The majority of ClO₂ used today is generated and dosed on site, ensuring both safety and cost‑effectiveness.

Today

With proven performance and a strong safety record, Chlorine Dioxide continues to grow as a preferred biocide, offering powerful disinfection while reducing many of the drawbacks associated with traditional chlorine treatment.

At ChloroKlean, we proudly supply both Chlorine Dioxide and Liquid Chlorine, working alongside global manufacturing leaders to ensure our customers benefit from the latest, most effective solutions available.