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For large-scale use, helium is extracted by fractional distillation from natural gas, which can contain as much as 7% helium. [148] Since helium has a lower boiling point than any other element, low temperatures and high pressure are used to liquefy nearly all the other gases (mostly nitrogen and methane). The resulting crude helium gas is ...
Helium has several unique qualities when compared with other elements: its boiling point at 1 atm is lower than those of any other known substance; it is the only element known to exhibit superfluidity; and, it is the only element that cannot be solidified by cooling at atmospheric pressure [29] (an effect explained by quantum mechanics as its ...
This list is sorted by boiling point of gases in ascending order, but can be sorted on different values. "sub" and "triple" refer to the sublimation point and the triple point, which are given in the case of a substance that sublimes at 1 atm; "dec" refers to decomposition. "~" means approximately. Blue type items have an article available by ...
Helium is the smallest and the lightest noble gas and one of the most unreactive elements, so it was commonly considered that helium compounds cannot exist at all, or at least under normal conditions. [1] Helium's first ionization energy of 24.57 eV is the highest of any element. [2]
The most common molecules within Earth's exosphere are those of the lightest atmospheric gases. Hydrogen is present throughout the exosphere, with some helium , carbon dioxide , and atomic oxygen near its base.
The abundance of the chemical elements is a measure of the occurrences of the chemical elements relative to all other elements in a given environment. Abundance is measured in one of three ways: by mass fraction (in commercial contexts often called weight fraction), by mole fraction (fraction of atoms by numerical count, or sometimes fraction of molecules in gases), or by volume fraction.
The most common isotope, 4 He, is produced on Earth by alpha decay of heavier elements; the alpha particles that emerge are fully ionized 4 He nuclei. 4 He is an unusually stable nucleus because it is doubly magic. It was formed in enormous quantities in Big Bang nucleosynthesis. Terrestrial helium consists almost exclusively (all but ~2ppm ...
[8]: 8 The remaining gases are often referred to as trace gases, [9] among which are other greenhouse gases, principally carbon dioxide, methane, nitrous oxide, and ozone. Besides argon, other noble gases, neon, helium, krypton, and xenon are also present. Filtered air includes trace amounts of many other chemical compounds.