- 1. A gaseous element, atomic no. 1, atomic wt. 1.00794. 2. The molecular form (H2) of the element. SYN: dihydrogen. [hydro- + G. -gen, producing]- activated h. h. removed by a dehydrogenase, e.g., via a flavoprotein, from a metabolite for transference to another substance with which it combines.- arseniureted h. SYN: arsine.- h. bromide HBr; a colorless gas that has a very irritating odor and fumes in moist air; in aqueous solution, it is hydrobromic acid.- h. dehydrogenase a flavoprotein catalyzing the conversion of NAD+ to NADH by molecular h. (H2); i.e., H2 + NAD+ → H+ + NADH.- heavy h. SYN: h.-2.- h. peroxide an unstable compound readily broken down to water and oxygen, a reaction catalyzed by various powdered metals and by the enzyme, catalase; a 3% solution is used as a mild antiseptic for skin and mucous membranes. SYN: h. dioxide, hydroperoxide.- phosphureted h. SYN: phosphine.- h. sulfide H2S; a colorless, flammable, toxic gas with a familiar “rotten egg” odor, formed in the decomposition of organic matter containing sulfur; used as a reagent, and in the manufacture of chemicals. SYN: sulfureted h..
* * *hy·dro·gen 'hī-drə-jən n a nonmetallic element that is the simplest and lightest of the elements and that is normally a colorless odorless highly flammable diatomic gas symbol H see DEUTERIUM, TRITIUM ELEMENT (table)hy·drog·e·nous hī-'dräj-ə-nəs adj
* * *hy·dro·gen (H) (hiґdro-jən) [hydro- + Gr. gennan to produce] the lightest element, an odorless, tasteless, colorless gas that is inflammable and explosive when mixed with air. It is found in water and in almost all organic compounds. Its ion is the active constituent of all acids in the water system. Atomic number 1, atomic weight 1.00797, specific gravity 0.069. Hydrogen exists in three isotopes: ordinary, or light, hydrogen is the mass 1 isotope, also called protium; heavy hydrogen is the mass 2 isotope, also called deuterium; the mass 3 isotope is tritium.
Medical dictionary. 2011.