According to theoretical calculations, it would have been much more stable (although still undergoing β + decay to deuterium) if the strong interaction had been 2% greater. Its nucleus, a diproton, consists of two protons with no neutrons. Is an extremely unstable isotope of helium. ^ a b Produced during Big Bang nucleosynthesisĪre the only stable nuclides with more protons than neutrons.^ Intermediate in the proton–proton chain reaction.^ # – Values marked # are not purely derived from experimental data, but at least partly from trends of neighboring nuclides (TNN).^ ( ) spin value – Indicates spin with weak assignment arguments.^ Bold symbol as daughter – Daughter product is stable.^ ( ) – Uncertainty (1 σ) is given in concise form in parentheses after the corresponding last digits.Dilution refrigerators take advantage of the immiscibility of these two isotopes to achieve temperatures of a few millikelvins. The different formation processes of the two stable isotopes of helium produce the differing isotope abundances.īelow 0.8 K separate into two immiscible phases due to differences in quantum statistics: 4Ītoms are fermions. Rocks from the Earth's crust have isotope ratios varying by as much as a factor of ten this is used in geology to investigate the origin of rocks and the composition of the Earth's mantle. Is 1.62(29) ×10 −4, which is 121(22) times higher than that of atmospheric helium. In the Local Interstellar Cloud, the proportion of 3 However, the isotopic abundance of helium varies greatly depending on its origin. In the Earth's atmosphere, the ratio of 3 , with a half-life of 260(40) yoctoseconds ( 2.6(4) ×10 −22 s), although it is possible that 2 With a half-life of 806.92(24) milliseconds. All radioisotopes are short-lived, the longest-lived being 6 Please let us know how we can improve this web app.Although there are nine known isotopes of helium ( 2He) ( standard atomic weight: 4.002 602(2)), only helium-3 ( 3 Related: Molecular weights of amino acids

Weights of atoms and isotopes are from NIST article. Molar mass ( molar weight) is the mass of one mole of a substance and is expressed in g/mol.(1 u is equal to 1/12 the mass of one atom of carbon-12)

Molecular mass ( molecular weight) is the mass of one molecule of a substance and is expressed in the unified atomic mass units (u).

To calculate molecular weight of a chemical compound enter it's formula, specify its isotope mass number after each element in square brackets.Įxamples of molecular weight computations:ĭefinitions of molecular mass, molecular weight, molar mass and molar weight Molar mass calculator also displays common compound name, Hill formula, elemental composition, mass percent composition, atomic percent compositions and allows to convert from weight to number of moles and vice versa.Ĭomputing molecular weight (molecular mass)

Functional groups: D, Ph, Me, Et, Bu, AcAc, For, Ts, Tos, Bz, TMS, tBu, Bzl, Bn, Dmg.

Capitalize the first letter in chemical symbol and use lower case for the remaining letters: Ca, Fe, Mg, Mn, S, O, H, C, N, Na, K, Cl, Al. Computing molar mass (molar weight)To calculate molar mass of a chemical compound enter its formula and click 'Compute'.

Mmass of helium