hydrogen

(H) [hi´dro-jen]

a chemical element, atomic number 1, atomic weight 1.00797. (See Appendix 6.) It exists as the mass 1 isotope (protium, or light or ordinary hydrogen), mass 2 isotope (deuterium, heavy hydrogen), and mass 3 isotope (tritium).

hydrogen cyanide an extremely poisonous colorless liquid or gas, HCN, a decomposition product of various naturally occurring glycosides and a common cause of cyanide poisoning. Inhalation of the gas can cause death within a minute. Called also hydrocyanic acid.

heavy hydrogen deuterium.

hydrogen ion concentration the degree of concentration of hydrogen ions (the acid element) in a solution. Its symbol is pH, and it expresses the degree to which a solution is acidic or alkaline. The pH range extends from 0 to 14, pH 7 being neutral, a pH of less than 7 indicating acidity, and one above 7 indicating alkalinity. See also acid-base balance.

hydrogen peroxide H₂O₂, an antiseptic with a mildly antibacterial action. A 3 per cent solution foams on touching skin or mucous membrane and appears to have a mechanical cleansing action.

hydrogen sulfide H₂S, a poisonous gas with an offensive smell, released from decaying organic material, natural gas, petroleum, and sulfur deposits, and sometimes used as a chemical reagent.

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References in periodicals archive

The very high ratio of heavy hydrogen (deuterium) to the common sort in what little water vapor remains says that there was once 100 times or so more, enough to make a wading pool over the surface, if not an ocean.

Water, water everywhere (and perhaps a few drops to drink

Investigating the hydrogen isotopes in the plaster provided a link to one suspect, whose living room air was similarly enriched in heavy hydrogen, a team reported in January in the Journal of Forensic Sciences.

Chemists want you to know that atomic weights aren't constant: revisions reflect variations in abundances of isotopes

In both sets of experiments, the researchers used chilled acetone in which hydrogen atoms had been replaced by deuterium, or heavy hydrogen, which fuses more readily than ordinary hydrogen does.

Once-maligned claim rebounds

Last year, nuclei of heavy hydrogen and of gold were slammed against each other at RHIC.

Nuclear pudding--to go

The wire cage vaporizes, collapsing inward and radiating X-rays toward a sesame-seed-size capsule of heavy hydrogen. This heats and squeezes the hydrogen until some of it fuses into helium and tritium nuclei.

Fusion device crosses threshold. (Physics)

There, scientists zapped clusters of atoms of deuterium, or heavy hydrogen, with brief but extremely powerful laser pulses.

Nuclear Fusion Flares on a Tabletop

researchers who measured the ratio of heavy hydrogen, or deuterium, to ordinary hydrogen in water in Comet Hale-Bopp.

Earth, water, and comets

The target typically consists of a vapor of heavy hydrogen isotopes (tritium and deuterium) encased in plastic.

Sparking fusion: a step toward laser-initiated nuclear fusion reactions

When a current passes between the electrodes, the water molecules break apart and spectacular amounts of deuterium nuclei (a heavy hydrogen isotope) cram into the palladium metal, where Pons and Fleischmann continue to argue fusion occurs.

Cold fusion keeps its head just above water