HF

HF, Hf or hf can refer to:

Biology

  • Holstein-Friesian, HF, a breed of cattle
  • Chemistry

  • Hafnium, Hf, a chemical element
  • Hartree–Fock method, a calculation scheme in the field of computational chemistry
  • Hydrogen fluoride, HF, a diatomic compound which can dissolve in water to form hydrofluoric acid, a highly corrosive solution
  • Hydrofluoric acid, HF(aq), a solution of hydrogen fluoride (HF) in water
  • Computing

  • Helicon Filter, photo editing software
  • Helicon Focus, a photo-merging program used to increase depth of field or make panoramas
  • Technology

  • High frequency, the ITU 3–30 MHz radio frequency range (band)
  • Handsfree, equipment that can be used without the use of hands
  • Medicine

  • Heart failure
  • Organizations and groups

  • Humanity First, an international charitable organisation, which focuses on immediate disaster response and long term development
  • Health trust (Helseforetak), a Norwegian hospital enterprise
  • Heritage Front, a white supremacist and Canadian Nationalist group
  • Hudobný fond (Music Fund Slovakia, HF), a presenter of the ZAI Awards
  • H1F0

    H1 histone family, member 0 is a member of the histone family of nuclear proteins which are a component of chromatin. In humans, this protein is encoded by the H1F0 gene.

    References

    Fluoronium

    Fluoronium (systematically named fluoranium, and μ-fluorido-dihydrogen(1+)) is an inorganic cation with the chemical formula H
    2
    F+
    (also written [H
    2
    F]+
    ). It contributes no colour to fluoronium salts. It is a very strong acid, and dilute fluoronium solutions are corrosive and can attack the skin. It can be formed by protonation or self-ionic dissociation of hydrogen fluoride:

    or

    The fluoronium ion is isoelectronic with water and the amide ion.

    Whereas stable organic structures containing other halonium ions have been known since 1970, a fluoronium analog was not known until 2013 and even then only as an unstable short-lived entity.

    The kinetic instability of the fluoronium ion is responsible for the extreme acidity of fluoroantimonic acid. The antimony pentafluoride molecule sequesters the fluoride ion produced by the homoassociation of hydrogen fluoride, leaving the fluoronium ion unable to revert to the more stable neutral hydrogen fluoride.

    References

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