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  2. Helium hydride ion - Wikipedia

    en.wikipedia.org/wiki/Helium_hydride_ion

    Unlike the helium hydride ion, the neutral helium hydride molecule HeH is not stable in the ground state. However, it does exist in an excited state as an excimer (HeH*), and its spectrum was first observed in the mid-1980s. [19] [20] [21] The neutral molecule is the first entry in the Gmelin database. [4]

  3. Helium compounds - Wikipedia

    en.wikipedia.org/wiki/Helium_compounds

    It was the first known triatomic helium van der Waals molecule. It can be detected by fluorescence. HeI 2 has a similar optical spectrum to I 2, except that the bands and lines are shifted to form two extra series. One series is blueshifted by between 2.4 and 4.0 cm −1, and the other between 9.4 and 9.9 cm −1. The two series may be due to ...

  4. Valence (chemistry) - Wikipedia

    en.wikipedia.org/wiki/Valence_(chemistry)

    Thus, each sulfur atom is hexavalent or has valence 6, but has oxidation state +5. In the dioxygen molecule O 2, each oxygen atom has 2 valence bonds and so is divalent (valence 2), but has oxidation state 0. In acetylene H−C≡C−H, each carbon atom has 4 valence bonds (1 single bond with hydrogen atom and a triple bond with the other ...

  5. Molecular orbital diagram - Wikipedia

    en.wikipedia.org/wiki/Molecular_orbital_diagram

    A diatomic molecular orbital diagram is used to understand the bonding of a diatomic molecule. MO diagrams can be used to deduce magnetic properties of a molecule and how they change with ionization. They also give insight to the bond order of the molecule, how many bonds are shared between the two atoms. [12]

  6. Binary compounds of hydrogen - Wikipedia

    en.wikipedia.org/wiki/Binary_compounds_of_hydrogen

    Binary hydrogen compounds in group 1 are the ionic hydrides (also called saline hydrides) wherein hydrogen is bound electrostatically. Because hydrogen is located somewhat centrally in an electronegative sense, it is necessary for the counterion to be exceptionally electropositive for the hydride to possibly be accurately described as truly behaving ionic.

  7. Isotopes of helium - Wikipedia

    en.wikipedia.org/wiki/Isotopes_of_helium

    2 He is an intermediate in the first step of the proton–proton chain. The first step of the proton-proton chain is a two-stage process: first, two protons fuse to form a diproton: 1 H + 1 H + 1.25 MeV → 2 He; then the diproton immediately beta-plus decays into deuterium: 2 He → 2 H + e + + ν e + 1.67 MeV; with the overall formula

  8. Beryllium monohydride - Wikipedia

    en.wikipedia.org/wiki/Beryllium_monohydride

    Beryllium monohydride (BeH) is an example of a molecule with a half-bond order according to molecular orbital theory. It is a metastable monoradical species which has only been observed in the gas phase. In beryllium monohydride, beryllium has a valency of one, and hydrogen has a valency of one.

  9. Helium atom - Wikipedia

    en.wikipedia.org/wiki/Helium_atom

    A helium atom is an atom of the chemical element helium. Helium is composed of two electrons bound by the electromagnetic force to a nucleus containing two protons along with two neutrons, depending on the isotope , held together by the strong force .