Chemistry:Thioarsenite

Subunit of the structure of proustite, a sulfosalt mineral. This picture shows the connectivity of the thioarsenite trianion to Ag⁺ (arsenic is colored violet).

Thioarsenite, also called sulfarsenite, is the trianion AsS₃³⁻. It is a pyramidal anion, as is typical of other As(III)X₃ compounds. It is generated by treatment of As₂S₃ with a sulfide:

As₂S₃ + 3 S²⁻ → 2 AsS₃³⁻

Thioarsenites are components of many sulfosalt minerals. An example is relatively common mineral proustite, Ag₃AsS₃.