How Is Arsenic Oxychloride Synthesized?

Arsenic oxychloride, also known as arsenic(III) oxychloride, can be synthesized using various methods. Here are two commonly used methods:

1. Direct synthesis method:

In this method, arsenic trioxide (As2O3) is reacted with thionyl chloride (SOCl2) in the presence of a dehydrating agent such as aluminum chloride (AlCl3). The reaction takes place at high temperature and yields arsenic oxychloride along with sulfur dioxide gas.

As2O3 + 6 SOCl2 + 2 AlCl3 → 2 AsOCl3 + 6 SO2 + 2 AlCl4

2. Indirect synthesis method:

This method involves the reaction of arsenic trichloride (AsCl3) with water to form arsenic acid (H3AsO4), which is then treated with thionyl chloride to form arsenic oxychloride.

AsCl3 + 3 H2O → H3AsO4 + 3 HCl

H3AsO4 + 2 SOCl2 → AsOCl3 + 2 SO2 + 2 HCl

After synthesis, the product is usually purified by distillation under vacuum to remove any impurities. It is important to note that arsenic oxychloride is highly toxic and should be handled with care in a well-ventilated area with appropriate protective measures.