HWHM (Half Width at Half Maximum), 691 hybrid material, 691 hybrid orbital, 691 hybrid polymer, 692 hybridization, 692 hybridoma, 692 hydration, 692 hydrazides, 693hydrazidines, 693 hydrazines, 693 hydrazinylidenes, 693 hydrazo compounds, 694 hydrazones, 694 hydrazonic acids, 694 hydrocarbons, 694 hydrocarbyl groups, 694 hydrocarbylene groups, 695 hydrocarbylidene groups, 695 hydrocarbylidyne groups, 695 hydrocarbylsulfanyl nitrenes, 695 hydrocracking unit, 696 hydrodynamic volume in polymers, 696 hydrodynamically equivalent sphere in polymers , 696 hydrogel, 696 hydrogen, 696 hydrogen bond, 697 hydrogen bond in theoretical organic chemistry , 697 hydrogen gas electrode, 697 hydrolases, 698 hydrolysis, 698 hydrolysis ratio, , 698 hydrometeor in atmospheric chemistry , 698 hydron, 698 hydroperoxides, 699 hydrophilic, 699 hydrophilicity, 699 hydrophobic interaction, 699 hydrophobicity, 699 hydropolysulfides, 700 hydrosphere in atmospheric chemistry , 700 hydrosulfides, 700 hydroxamic acids, 700 hydroximic acids, 700 hydroxylamines, 701 hygrometer, 701 hygrometry (moisture analysis), 701 hyperchromic effect, 701 hyperconjugation, 701 hypercoordination, 702 hyperfine coupling, 703 hyperfine (interaction), 703 hyperpolarizability (of nth order), 703 hypervalency, 704 hypho -, 704 hypo-phase, 704 hypochromic effect, 704 hypsochromic shift, 704 hysteresis, 705