[{"from": "human", "value": "Describe this molecule. [F]"}, {"from": "gpt", "value": "The molecule is a solution of hydrogen fluoride (HF) in water. It is a precursor to almost all fluorine compounds, including pharmaceuticals such as fluoxetine (Prozac), surface coatings such as PTFE (Teflon), and elemental fluorine itself. Hydrofluoric acid is classified as a weak acid because of its lower dissociation constant compared to the strong acids. Hydrofluoric acid is produced by treatment of the mineral fluorite (CaF2) with concentrated sulfuric acid. When combined at 265 \u00b0C, these two substances react to produce hydrogen fluoride and calcium sulfate.  HF is used in oil refining, the production of organofluorines, fluorides and glass etching.  Hydrofluoric acid is also used for dissolving rock samples (usually powdered) prior to analysis."}]