Image Hydrogen fluoride molecule

TLF ID R6860

This is a colour image of a model of a molecule of hydrogen fluoride, HF. In this model, atoms are represented by coloured spheres held together by grey rods, representing covalent bonds. The hydrogen fluoride molecule contains one hydrogen atom (the smaller grey-white sphere) and one fluorine atom (the blue-grey sphere).



Educational details

Educational value
  • Hydrogen fluoride is a highly toxic, corrosive, colourless gas at room temperature. It condenses to a liquid at 19.5 degrees Celsius. The liquid is widely used in industry as a solvent. Hydrogen fluoride dissolves in water to form hydrofluoric acid, which is used to remove rust.
  • The atoms in the molecule are connected by a single covalent bond. A covalent bond is formed when atoms share electrons, and a single covalent bond has two shared electrons, one contributed by each atom.
  • The electrons in the bond are not shared equally; they are attracted more strongly to the fluorine. This results in the hydrogen fluoride molecule having an electric dipole, and consequently the molecules are strongly attracted to each other. This unusually strong attraction is termed ‘hydrogen bonding’. The strength of the hydrogen bonding explains why hydrogen fluoride has a much higher boiling point than the hydrogen compounds of the other halogens.
  • The type of model shown here, called a ball-and-stick model, is one of several ways of modelling molecules. This type is useful because it clearly shows the geometry of the molecule and the order (single, double or triple) of the bonds. However, because 'sticks' are used to represent bonds, this type of model does not represent the actual shape of the molecule as well as 'space-filling' models do.
Year level

7; 8; 9; 10; 11; 12

Learning area
  • science
Strand
  • Science/Science understanding

    Other details

    Contributors
    • Publisher
    • Date of contribution: 20 Sep 2013
    • Organisation: Education Services Australia
    • Address: Melbourne VIC 3000 Australia
    • URL: http://www.esa.edu.au/
    • Copyright holder
    • Organisation: Education Services Australia
    • Address: Melbourne VIC 3000 Australia
    • URL: http://www.esa.edu.au/
    • Remarks: Copyright Education Services Australia Ltd
    • Author
    • Date of contribution: 2006
    • Organisation: Education Services Australia
    • Address: Melbourne VIC 3000 Australia
    • URL: http://www.esa.edu.au/
    • Remarks: creator
    • Content provider
    • Organisation: Education Services Australia
    • Address: Melbourne VIC 3000 Australia
    • URL: http://www.esa.edu.au/
    Access profile
    • Device independence
    • Hearing independence
    Learning resource type
    • Image
    Browsers
    • Microsoft Internet Explorer - minimum version: 8.0 (MS-Windows) - maximum version: 9.0 (MS-Windows)
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    • Safari - minimum version: 5.1 (MacOS)
    Operating systems
    • MacOS - minimum version: 10.6
    • MS-Windows - minimum version: XP - maximum version: 7
    Rights
    • © Education Services Australia Ltd, 2013, except where indicated under Acknowledgments