Lime sulfur

Chemical mixture used as a pest control agent In horticulture, lime sulfur (lime sulphur in British English; see American and British English spelling differences) is mainly a mixture of calcium polysulfides and thiosulfate (plus other reaction by-products such as sulfite and sulfate), formed by reacting calcium hydroxide with elemental sulfur, and is used in pest control. It can be prepared by boiling a suspension of poorly soluble calcium hydroxide (lime) and solid sulfur in water, together with a small amount of surfactant to facilitate the dispersion of these solids. After elimination of residual solids (flocculation, decantation, and filtration), it is normally used as an aqueous solution, which is reddish-yellow in color and has a distinctive offensive odor of hydrogen sulfide (H2S, rotten eggs). Synthesis reaction The exact chemical reaction leading to the synthesis of lime sulfur is generally written as: Ca(OH)2 + x/8 S8 → CaSx + by-products (S2O2−3, SO2−3, SO2−4) as reported in a document of the US Department of Agriculture (USDA). This reaction is poorly understood because it is vague and involves the reduction of elemental sulfur, and no reductant appears in the