hydrogen fluoride (HF)A colorless liquid, fuming in air; a covalent hydride, preparing by distilling fluorite with concentrated sulfuric acid. Its physical properties showing typical anomalies due to hydrogen bonding. Hydrogen fluoride is a very strong acid, and an ionizing solvent for many inorganic and organic compounds; it is used to make fluorine and its compounds, especially freon and fluorocarbons. Melting point -83°C, boiling point 20°C. Hydrofluoric acid, a solution of hydrogen fluoride in water, is (anomalously) a weak acid, but causes very severe burns and is toxic. It dissolves silica to give fluorosilicic acid (H2SiF6), and so is used to etch glass. Related category• INORGANIC CHEMISTRYAlso on this site: Encyclopedia of Alternative Energy & Sustainable Living Encyclopedia of History |