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Helium. hexagonal close-packed (hcp) Helium (from Greek: ἥλιος, romanized: helios, lit. 'sun') is a chemical element; it has symbol He and atomic number 2. It is a colorless, odorless, non-toxic, inert, monatomic gas and the first in the noble gas group in the periodic table.
There is disagreement in the literature for some line designations; for example, the Fraunhofer d line may refer to the cyan iron line at 466.814 nm, or alternatively to the yellow helium line (also labeled D 3) at 587.5618 nm. Similarly, there is ambiguity regarding the e line, since it can refer to the spectral lines of both iron (Fe) and ...
The Balmer series is characterized by the electron transitioning from n ≥ 3 to n = 2, where n refers to the radial quantum number or principal quantum number of the electron. The transitions are named sequentially by Greek letter: n = 3 to n = 2 is called H-α, 4 to 2 is H-β, 5 to 2 is H-γ, and 6 to 2 is H-δ.
September 9, 2024 at 9:10 AM. (Reuters) - The global demand for helium is likely to nearly double by 2035, backed mostly by a rise in demand from the semiconductor industry due to the lack of ...
On Thursday, the U.S. government sold the Federal Helium Reserve, a massive underground stockpile based in Amarillo, Texas, that supplies up to 30% of the country’s helium.
The Crude Helium Enrichment Unit in the Cliffside Gas Field. Remnants of the Amarillo Helium Plant in 2015. The National Helium Reserve, also known as the Federal Helium Reserve, is a strategic reserve of the United States, which once held over 1 billion cubic meters (about 170,000,000 kg) [a] of helium gas.
Helium also has a very low boiling point (-268.9°C or -452°F), allowing it to remain a gas even in super-cold environments, an important feature because many rocket fuels are stored in that ...
The Pickering series (also known as the Pickering–Fowler series) consists of three lines of singly ionised helium found, usually in absorption, in the spectra of hot stars like Wolf–Rayet stars. The name comes from Edward Charles Pickering [1] and Alfred Fowler. [2] The lines are produced by transitions from a higher energy level of an ...