Caesium Fluoride, known chemically as CsF

Caesium Fluoride, known chemically as CsF, is an inorganic compound with the formula CsF and a molecular weight of approximately 151.90. It is characterized by its white cubic crystal form and is highly deliquescent, meaning it readily absorbs moisture from the air. Classified as highly toxic, caesium fluoride has a specific gravity of 4.115 and exhibits a melting point of 682°C and a boiling point of 1251°C. It is the most soluble of the caesium salts and dissolves readily in water and methanol, but is insoluble in pyridine.

Industrially, caesium fluoride is utilized in a variety of applications. It serves as an analytical reagent and is used in the manufacturing of optical crystals. Additionally, it is employed in the production of fluoroisocyanates and plays a significant role in the Suzuki cross-coupling reaction as a base for the ortho-substitution of biaryls. It also acts as a nucleophile in the fluorination of primary halides and sulfonates in protonic media such as tert-butyl or tert-amyl alcohols. Furthermore, caesium fluoride is used as a catalyst in the reaction with carbonyl compounds to form silyl enol ethers and is effective in the synthesis of single-crystal Dion-Jacobson phase CsLaTa2O7, which has applications in photocatalysis and superconductivity.

Safety is a critical consideration when handling caesium fluoride due to its poisonous nature. It is classified with hazard codes H302 (harmful if swallowed), H315 (causes skin irritation), H318 (causes serious eye damage), and H361 (suspected of damaging fertility or the unborn child). It is essential to follow safety measures such as wearing protective gloves, clothing, eye protection, and respiratory equipment when working with this substance. In case of contact with skin or eyes, immediate rinsing with water is necessary, followed by seeking medical attention. When heated to decomposition, caesium fluoride emits toxic fumes of hydrogen fluoride and caesium oxides. It is important to store caesium fluoride in a cool, dry place, away from acids, and to dispose of it according to local regulations.