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 is the trianion AsS₃^3-. It is a pyramidal anion, as it typical for other As(III)X₃ compounds. It is also called sulfarsenite. It is generated by treatment of As2S3 with sulfide:

As₂S₃ + 3 S^2- → 2 AsS₃^3-

Thioarsenites are components of many sulfosalt minerals. An example is relatively common mineral proustite, Ag₃AsS₃.^[1][2][3]

References

1. Mindat
2. Webmineral
3. Trevelyan B. 1969: The electro-optic effect in proustite. Optical and Quantum Electronics, 1(1), pp. 1969;