Sodium pentachlorophenate is a chemical compound used as a biocide and preservative in various industrial and agricultural applications. It is an organochlorine compound with five chlorine atoms attached to a phenolic ring structure. Sodium pentachlorophenate is effective at inhibiting the growth of bacteria, fungi, and algae, making it useful in the preservation of wood, leather, and other materials.

One of its primary applications is as a wood preservative, where it helps protect wooden structures from decay and deterioration caused by microorganisms and insects. Additionally, it has been used in the treatment of wastewater and as a disinfectant in various industrial processes. However, the use of sodium pentachlorophenate has declined due to environmental concerns associated with organochlorine compounds, as they can persist in the environment and potentially pose risks to ecosystems and human health.