• WordNet 3.6
    • n hydrogen a nonmetallic univalent element that is normally a colorless and odorless highly flammable diatomic gas; the simplest and lightest and most abundant element in the universe
    • ***
Webster's Revised Unabridged Dictionary
  • Interesting fact: Hydrogen gas is the least dense substance in the world, at 0.08988g/cc
    • n Hydrogen (Chem) A gaseous element, colorless, tasteless, and odorless, the lightest known substance, being fourteen and a half times lighter than air (hence its use in filling balloons), and over eleven thousand times lighter than water. It is very abundant, being an ingredient of water and of many other substances, especially those of animal or vegetable origin. It may by produced in many ways, but is chiefly obtained by the action of acids (as sulphuric) on metals, as zinc, iron, etc. It is very inflammable, and is an ingredient of coal gas and water gas. It is standard of chemical equivalents or combining weights, and also of valence, being the typical monad. Symbol H. Atomic weight 1.☞ Although a gas, hydrogen is chemically similar to the metals in its nature, having the properties of a weak base. It is, in all acids, the base which is replaced by metals and basic radicals to form salts. Like all other gases, it is condensed by great cold and pressure to a liquid which freezes and solidifies by its own evaporation. It is absorbed in large quantities by certain metals (esp. palladium), forming alloy-like compounds; hence, in view of quasi-metallic nature, it is sometimes called hydrogenium. It is the typical reducing agent, as opposed to oxidizers, as oxygen, chlorine, etc.
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Century Dictionary and Cyclopedia
  • Interesting fact: Hydrogen is the most common atom in the universe
    • n hydrogen Chemical symbol, H. One of the elementary substances, existing as a colorless, tasteless, and inodorous gas. It is the lightest substance known, and for that reason its specific gravity has been taken as the unit for comparing the specific gravity of gases, though air is the more commonly accepted standard. Under like conditions of temperature and pressure, hydrogen is approximately 14.4 times as light as an equal volume of air. Its combining weight is also less than that of any other element, and is therefore called unity, all the other atomic weights being expressed as multiples of it. It is but slightly soluble in water or any other liquid. Hydrogen refracts light strongly, is extremely diffusible, and is absorbed or occluded in a remarkable manner by certain metals when they are heated, as though it formed a kind of alloy with them. Hydrogen burns in air with a very pale blue flame and intense heat, the sole product of combustion being water, H2O, which is the protoxid of hydrogen. A mixture of two volumes of hydrogen and six of air or one of oxygen explodes violently when brought in contact with a flame or the electric spark. Hydrogen is not specifically poisonous when inhaled, but is fatal to life by preventing or hindering access of oxygen to the blood. It is prepared by the action of dilute sulphuric acid on zinc or iron, by passing steam through a red-hot tube filled with iron turnings, by the electrolysis of water, and in a variety of other ways. Hydrogen occurs free in nature in small quantity in the emanations of volcanoes and of some oil-wells, but generally it is found only in its combinations, which are universally distributed. One ninth of the weight of water consists of hydrogen, and it is an indispensable element of every animal or vegetable structure. It is a component of all acids, and its replacement in them by bases produces salts. In December, 1877, and January, 1878, the French chemists Cailletet and Pictet succeeded in liquefying hydrogen, and the latter in solidifying it, by means of extreme pressure and cold produced in special forms of apparatus independently invented by them.
    • n hydrogen H2S, a colorless inflammable gas having a sweetish taste and an exceedingly fetid smell resembling rotten eggs. It is extremely poisonous when inhaled. It has feeble acid properties, and its compounds with bases are called sulphids. It occurs in the emanations of volcanoes, and is evolved when animal or vegetable tissue containing sulphur decays. It also occurs in mineral springs, being liberated by the reduction of gypsum or other sulphates through the action of a microbe.
    • n hydrogen Hydrogen compounds with strongly electronegative elements or radicals, easily exchanging hydrogen for strongly electropositive elements or radicals to form salts, are the same as acids: as hydrogen chlorid (hydrochloric acid), hydrogen sulphate (sulphuric acid), etc.
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Chambers's Twentieth Century Dictionary
  • Interesting fact: The sun is approximately 75% hydrogen, 25% helium by mass
    • n Hydrogen hī′dro-jen a gas which in combination with oxygen produces water, an elementary gaseous substance, the lightest of all known substances, and very inflammable
    • ***


  • George Sweeting
    George Sweeting
    “I lose my temper, but it's all over in a minute, said the student. So is the hydrogen bomb, I replied. But think of the damage it produces!”
  • Harlan Ellison
    Harlan Ellison
    “The two most common elements in the universe are hydrogen and stupidity.”


Webster's Revised Unabridged Dictionary
Hydro-, 1 + -gen,: cf. F. hydrogène,. So called because water is generated by its combustion. See Hydra
Chambers's Twentieth Century Dictionary
A word coined by Cavendish (1766) from Gr. hydōr, water, and genēs, producing.


In literature:

Have a little more sulphuretted hydrogen.
"The Willoughby Captains" by Talbot Baines Reed
A valuable remedy is Peroxide of Hydrogen used full strength and freely dropped into the nostril.
"The Eugenic Marriage, Volume IV. (of IV.)" by Grant Hague
Do not young ladies learn, from books, how to make hydrogen and oxygen?
"A Treatise on Domestic Economy" by Catherine Esther Beecher
They were at first attributed (by RYDBERG) to hydrogen and were called "additional lines of hydrogen".
"Lectures on Stellar Statistics" by Carl Vilhelm Ludvig Charlier
The action of hydrogen peroxide was specially investigated.
"Researches on Cellulose" by C. F. Cross
The action of the hydrogen in the volatile constituents of the fuel is to increase the apparent percentage of the nitrogen in the flue gases.
"Steam, Its Generation and Use" by Babcock & Wilcox Co.
Making Hydrogen and Oxygen.
"Electricity for Boys" by J. S. Zerbe
Even this should not be trusted too implicitly unless an oxygas or hydrogen flame is employed.
"On Laboratory Arts" by Richard Threlfall
Masses of hydrogen will stop neutrons, so we lived, and escaped in the tender.
"The Ultimate Weapon" by John Wood Campbell
Hydrogen fusion, same as the stellarator.
"Damned If You Don't" by Gordon Randall Garrett
This one, however, was carrying the complex mechanism of a hydrogen bomb.
"Pushbutton War" by Joseph P. Martino
You say it is formed of hydrogen and oxygen in such and such proportions.
"The Tyranny of the Dark" by Hamlin Garland
A balloon full of hydrogen "falls up" in obedience to the Law of Gravity.
"The Highest Treason" by Randall Garrett
Occasionally a perceptible smell of sulphuretted hydrogen is observed.
"The Voyage of the Vega round Asia and Europe, Volume I and Volume II" by A.E. Nordenskieold
Hydrogen dioxide occurs in a manner closely resembling ozone.
"Encyclopaedia Britannica, 11th Edition, Volume 2, Slice 8" by Various
In the case of methylene blue, reduction consists in the addition of two hydrogen atoms.
"The Nature of Animal Light" by E. Newton Harvey
Palladium and hydrogen, 178.
"The Phase Rule and Its Applications" by Alexander Findlay
But water contains too much hydrogen for that.
"The Romance of War Inventions" by Thomas W. Corbin
An inflammable gas, apparently hydrogen, was evolved during the fusion.
"Some Constituents of the Poison Ivy Plant: (Rhus Toxicodendron)" by William Anderson Syme
Here again the hydrosulphite takes up oxygen from the water and liberates the necessary hydrogen.
"Encyclopaedia Britannica, 11th Edition, Volume 8, Slice 8" by Various

In poetry:

I worry about this because I
love you. As if it weren't grotesque
enough that we live in hydrogen
and breathe like atomizers, you
have to think I'm a great architect!
"V.R. Lang" by Frank O Hara

In news:

Naturally solid palm oil blends can be used as a 1-1 substitute for partially hydrogenated vegetable oil s in most cases, and cost about the same as soybean oil.
The emergency vent system designed to help prevent hydrogen explosions failed to work in at least two of the three reactors in operation.
General Motors and BMW plan to announce today a joint venture to develop liquid hydrogen as a fuel for cars, a person close to the plan said yesterday.
Turn sewage sludge into hydrogen for use in fuel cell vehicles.
Support for government investment in alternative energy such as solar, wind and hydrogen power has slipped significantly over the past two years because of partisan polarization.
Published in the journal Nature, the researchers' method uses radio telescopes to seek out radio waves emitted by hydrogen atoms , which were abundant in the early days of the universe.
Unlike nearly all the other concepts shown, the Traffic Crawler is an actual manned vehicle, with a hydrogen fuel cell powering all three wheels.
First aid for wounds: Hydrogen peroxide.
Apple's hydrogen power plans fueled by Al Gore's conflict of interest .
A GM logo is seen on a Hydrogen car during a presentation in Berlin, August 28, 2009 REUTERS/Pawel Kopczynski.
Hydrogen powered concept is Nissan's crossover of the future.
Campers Get Look At Cutting Edge Hydrogen Fuel.
Train Derailment Crews Now Working on Hydrogen Fluoride Cars.
General Motors says it will close its hydrogen fuel-cell research operation near Rochester and move it to Michigan WAMC's Dave Lucas has more.
Plans to close its hydrogen fuel-cell research operation near Rochester, N.Y.

In science:

Overall, the neutral hydrogen distribution of UGC 12695 appears to match the optical morphology quite well, including the fact that the H I distribution is very lopsided with a high column density ridge running through the southern part of the disk.
Star Formation and Tidal Encounters with the Low Surface Brightness Galaxy UGC 12695 and Companions
It is noteworthy to point out that the three local peaks in the neutral hydrogen of UGC 12695 lie near, but not on top, the primary star formation regions of the galaxy, as defined by the H- α image of McGaugh (1994).
Star Formation and Tidal Encounters with the Low Surface Brightness Galaxy UGC 12695 and Companions
So it is proved that the cyclic oscillator is dual to the charge–dyon system, being a generalization of a usual two-dimensional hydrogen atom.
Dyon-Oscillator Duality
For the pure He ignition model, there is a peak in the buoyancy at the place where the hydrogen runs out (y ≈ yd ), at this depth the composition piece of the buoyancy dominates the thermal piece.
Rotational Evolution During Type I X-Ray Bursts
Thus, eWNE means WN stars without hydrogen, while eWNL means WN stars with hydrogen, (see also Sect 5 below).
Stellar evolution with rotation X: Wolf-Rayet star populations at solar metallicity
In Sec.3, the conclusions reached in Sec.2 will be applied to the case of the electron’s wave function in the hydrogen atom; particularly, to the Dirac and the Schr¨odinger models of the hydrogen atom.
Electrodynamics and the Mass-Energy Equivalence Principle
When we apply the force expression given by Eq.(28) to the case of the hydrogen atom (stable orbit), we note that Z = 1 for hydrogen.
Electrodynamics and the Mass-Energy Equivalence Principle
All ob jects to the right of the solid black line should have lost their hydrogen envelope by the point of collapse resulting in hydrogen-free SNe.
A Study of the Type II-P Supernova 2003gd in M74
Type I supernovae exh ibit no sign of hydrogen in their spectra while Type II do exhibit hydrogen.
Rates and Progenitors of Type Ia Supernovae
Type I superno vae exhibit no sign of hydrogen in their spectra while Type II do exhibit hydrogen.
Rates and Progenitors of Type Ia Supernovae
If the accumulated material is hydrogen, then the accreted matter may eventually be lost through explosive hydrogen burning on the surface of the white dwarf.
Rates and Progenitors of Type Ia Supernovae
The detection of hydrogen emission lines in the spectra of SN 2002ic in combination with the slow decay of the light curve is seen as evidence for interaction of the SN ejecta and radiation with a hydrogen-rich CSM (Hamuy et al. 2003; Wang et al. 2004).
Rates and Progenitors of Type Ia Supernovae
Another remark on importance of the hydrogen atom for QED is that the anomalous magnetic moment of an electron was first discovered by Rabi and his colleagues as an anomaly in the hyperfine structure of hydrogen.
Precision physics of simple atoms: QED tests, nuclear structure and fundamental constants
The first one is realized in ‘normal’ (electronic) hydrogen-like atoms (hydrogen, deuterium, helium ions etc.).
Precision physics of simple atoms: QED tests, nuclear structure and fundamental constants
We summarize in Tables 4 all accurate data available for the hyperfine intervals of the 1s and 2s states in conventional light hydrogen-like atoms (hydrogen, deuterium and tritium and in the helium-3 ion).
Precision physics of simple atoms: QED tests, nuclear structure and fundamental constants