Search results
Results from the WOW.Com Content Network
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]
Helium's first ionization energy of 24.57 eV is the highest of any element. [2] Helium has a complete shell of electrons, and in this form the atom does not readily accept any extra electrons nor join with anything to make covalent compounds. The electron affinity is 0.080 eV, which is very close to zero. [2]
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
Whereas the carbon–helium-ion bond breaks spontaneously and immediately to yield a carbocation, bonds of other elements to helium are more stable. For example, molecular tritium T 2 or tritium-hydrogen HT. On decay, these form a stable helium hydride ion [HeH] + (respectively [3 HeT] + or [3 HeH] +), which is stable enough to persist. This ...
The hydride reacts with the weak Bronsted acid releasing H 2. Hydrides such as calcium hydride are used as desiccants, i.e. drying agents, to remove trace water from organic solvents. The hydride reacts with water forming hydrogen and hydroxide salt. The dry solvent can then be distilled or vacuum transferred from the "solvent pot".
Helium, oxygen, neon, iron—they all come from the fusion that takes place in dying stars. But we have a lot of elements that are more massive than iron ; it’s only element 26 of 118, after all.
The first molecule detected in the interstellar medium was the methylidyne radical (CH •) in 1937, through its strong electronic transition at 4300 angstroms (in the optical). [4] Advances in astronomical instrumentation have led to increasing numbers of new detections.
Argonium (also called the argon hydride cation, the hydridoargon(1+) ion, or protonated argon; chemical formula ArH +) is a cation combining a proton and an argon atom. It can be made in an electric discharge , and was the first noble gas molecular ion to be found in interstellar space.