Hydrogen (H)
nonmetalGas
Peso atomico standard
1,008 u [1,00784, 1,00811]Configurazione elettronica
1s1Punto di fusione
-259,34 °CPunto di ebollizione
-252,87 °CDensità
0,08988 kg/m³Stati di ossidazione
−1, +1Elettronegatività (Pauling)
2,2Energia di ionizzazione (1ª)
13,598435 eVAnno della scoperta
1766Raggio atomico
25 pmDettagli
The lightest chemical element, hydrogen sits above the alkali metals but is a nonmetal under ordinary conditions. Its single proton and one electron make it the simplest atom and a reference point for much of chemistry. On Earth it is usually bound in water and organic matter, while industry uses it as a chemical feedstock, reducing agent, fuel, and energy carrier.
Colourless, odourless gaseous chemical element. Lightest and most abundant element in the universe. Present in water and in all organic compounds. Chemically reacts with most elements. Discovered by Henry Cavendish in 1776.
The name derives from the Greek hydro for "water" and genes for "forming" because it burned in air to form water. Hydrogen was discovered by the English physicist Henry Cavendish in 1766.
Scientists had been producing hydrogen for years before it was recognized as an element. Written records indicate that Robert Boyle produced hydrogen gas as early as 1671 while experimenting with iron and acids. Hydrogen was first recognized as a distinct element by Henry Cavendish in 1766. Composed of a single proton and a single electron, hydrogen is the simplest and most abundant element in the universe. It is estimated that 90% of the visible universe is composed of hydrogen.
Hydrogen is the raw fuel that most stars 'burn' to produce energy. The same process, known as fusion, is being studied as a possible power source for use on earth. The sun's supply of hydrogen is expected to last another 5 billion years.
From the Greek word hydro (water), and genes (forming). Hydrogen was recognized as a distinct substance by Henry Cavendish in 1776. Diagram of a simple hydrogen atom.
Hydrogen is the most abundant of all elements in the universe. The heavier elements were originally made from hydrogen atoms or from other elements that were originally made from hydrogen atoms.
Pure hydrogen at room temperature is a colorless, odorless, tasteless gas. It has no luster or visible texture and is much less dense than air. Liquid hydrogen is also colorless, forming only at very low temperatures near −253 °C under normal pressure.
Most hydrogen is used in chemical industry rather than burned as a fuel. It is essential for ammonia production by the Haber-Bosch process, petroleum refining, methanol manufacture, and hydrogenation of oils and other chemicals. It is also used in fuel cells, rocket propellants, metal processing, protective atmospheres, and laboratory work. Everyday life encounters hydrogen mainly through water, fuels, plastics, foods, and organic molecules.
Hydrogen is a commercially important element. Large amounts of hydrogen are combined with nitrogen from the air to produce ammonia (NH3) through a process called the Haber process. Hydrogen is also added to fats and oils, such as peanut oil, through a process called hydrogenation. Liquid hydrogen is used in the study of superconductors and, when combined with liquid oxygen, makes an excellent rocket fuel.
Hydrogen combines with other elements to form numerous compounds. Some of the common ones are: water (H2O), ammonia (NH3), methane (CH4), table sugar (C12H22O11), hydrogen peroxide (H2O2) and hydrochloric acid (HCl).
Hydrogen has three common isotopes. The simplest isotope, called protium, is just ordinary hydrogen. The second, a stable isotope called deuterium, was discovered in 1932. The third isotope, tritium, was discovered in 1934.
Great quantities of hydrogen are required commercially for nitrogen fixation using the Haber ammonia process, and for the hydrogenation of fats and oils. It is also used in large quantities in methanol production, in hydrodealkylation, hydrocracking, and hydrodesulfurization. Other uses include rocket fuel, welding, producing hydrochloric acid, reducing metallic ores, and filling balloons.
The lifting power of 1 cubic foot of hydrogen gas is about 0.07 lb at °C, 760 mm pressure.
The hydrogen fuel cell is a developing technology that will allow great amounts of electrical power to be obtained using a source of hydrogen gas.
Consideration is being given to an entire economy based on solar- and nuclear-generated hydrogen. Public acceptance, high capital investment, and the high cost of hydrogen with respect to today's fuels are but a few of the problems facing such an economy. Located in remote regions, power plants would electrolyze seawater; the hydrogen produced would travel to distant cities by pipelines. Pollution-free hydrogen could replace natural gas, gasoline, etc., and could serve as a reducing agent in metallurgy, chemical processing, refining, etc. It could also be used to convert trash into methane and ethylene.
Isotopes in Earth/Planetary Science
Molecules, atoms, and ions of the stable isotopes of hydrogen possess slightly different physical and chemical properties and they are commonly fractionated during physical, chemical, and biological processes, giving rise to variations in isotopic abundances and in atomic weights (Fig. IUPAC.1.1). Hydrogen has the largest relative mass difference among its isotopes and consequently exhibits the largest variation in isotopic composition of any element that does not have radioactive or radiogenic isotopes. Ranges in the stable isotopic composition of naturally occurring hydrogen-bearing materials are shown in Fig. IUPAC.1.1. These variations enable hydrogen isotopes to be used as tracers in environmental studies [13] M. W. Wieser, T. B. Coplen. Pure Appl Chem.83, 359 (2011)..
A primary use of stable hydrogen isotopes is in isotope hydrology. Although the evolution of the stable hydrogen and oxygen isotopic composition of precipitation begins with the evaporation of water from the oceans, their local and global relationship arises primarily from equilibrium isotopic fractionation of heavier (2H and 18O) and lighter (1H and 16O) isotopes of hydrogen and oxygen during condensation as a tropospheric vapor mass follows a trajectory to higher latitudes and over continents [14] W. Dansgaard. Tellus16, 436 (1964)., [15] I. D. Clark, P. Fritz. Environmental Isotopes in Hydrogeology, p. 328, Lewis Publishers, New York (1997).. As a consequence, the hydrogen isotopic composition of precipitation, rivers, and tap waters varies with elevation, season, and distance from the ocean-continent boundary. Figure 4.1.2 shows the variation in the atomic weight of hydrogen in water from rivers across the United States. These variations in the hydrogen isotopic composition of environmental water are often combined with stable oxygen isotopic compositions and have been used to identify the origin of water samples and to investigate the interaction between groundwater and surface water (e.g. lakes, streams, and rivers) [16] C. Kendall, T. B. Coplen. Hydrol. Processes.15, 1363 (2011)..
Isotopes in Forensic Science and Anthropology
Measurements of relative 2H abundances are used to determine the breeding grounds of many species of migrant songbirds. These species of songbirds only grow their feathers before migration, and they grow them on or close to their breeding grounds. Therefore, the isotopic composition of a bird’s feathers correlates to the isotopic composition of the growing season’s precipitation [18] Z. D. Sharp, V. Atudorei, H. O. Panarello, J. Fernández, C. Douthitt. J. Archaeolog. Sci.30, 1709 (2003)., [19] K. A. Hobson. Oecologia120, 314 (1999)., [20] K. A. Hobson, L. I. Wassenaar. Oecologia.109, 142 (1996)..
Measurements of relative 2H abundances of human hair samples collected at archeological sites are used to determine the geographic region in which a subject lived based on the hydrogen isotopic composition of the water they drank. This is possible because hair stores a daily record of the hydrogen isotopic composition of intake water, which correlates to local meteoric water [18] Z. D. Sharp, V. Atudorei, H. O. Panarello, J. Fernández, C. Douthitt. J. Archaeolog. Sci.30, 1709 (2003)., [21] T. B. Coplen, H. Qi. Forensic Sci. Int.266, 222 (2016)..
Isotopes in Geochronology
3H (tritium), with a half-life of 12.31 years, decays to 3He. The relative variations in n(3He)/n(3H) ratios can be interpreted in terms of elapsed time for dating purposes. The dates of groundwater recharge (water moving downward from the surface), where large amounts of 3H were received from precipitation following thermonuclear bomb test periods, come from the elapsed time since a water mass became isolated from the atmosphere in the time range from the mid-1950s to the present [15] I. D. Clark, P. Fritz. Environmental Isotopes in Hydrogeology, p. 328, Lewis Publishers, New York (1997)..
Isotopes in Industry
3H is used for self-luminous exit signs in aircraft and commercial buildings. It is found in luminous dials, gauges, wristwatches, and luminous paints [22] United States Nuclear Regulatory Commission. NRC: Fact Sheet on Tritium Exit Signs, (2013), November 12; http://www.nrc.gov/reading-rm/doc-collections/fact-sheets/fs-tritium.html.. 2H, in the form of heavy water, is used in CANDU (CANada Deuterium Uranium) nuclear reactors as a moderator and coolant [23] CANDU Owners Group Inc. CANDU Reactors, CANDU Owners Group Inc (2013), July 30; http://www.candu.org/candu_reactors.html..
Isotopes in Medicine
2H is used for the isotopic labeling of drugs and nutrients to trace their uptake and metabolism in the human body [24] S. P. O’Grady, A. R. Wende, C. H. Remien, L. O. Valenzuela, L. E. Enright, L. A. Chesson, E. D. Abel, T. E. Cerling, J. R. Ehleringer. PLoS One5, e11699 (2010). https://doi.org/10.1371/journal.pone.0011699., [25] M. van Lieshout, C. E. West, R. B. van Breemen. Am. J. Clin. Nutr.77, 12 (2003).. 2H, in the form of heavy water, is used to study human metabolism. For example, 2H is used in combination with 18O (double labeled water) to measure energy expenditure [26] D. A. Schoeller, E. Ravussin, Y. Schutz, K. J. Acheson, P. Baertschi, E. Jequier. Am. J. Physiol. Regul. Integr. Comp. Physiol.250, R823 (1986)..
Water (H₂O) is the most familiar hydrogen compound and the main reservoir of hydrogen at Earth’s surface. Methane (CH₄) is a major fuel and carbon feedstock. Ammonia (NH₃) is central to fertilizers and nitrogen chemistry. Hydrogen chloride (HCl) forms hydrochloric acid in water. Hydrogen peroxide (H₂O₂) is used as an oxidizer and disinfectant. Metal hydrides store or transfer hydrogen in some chemical and technical systems.
Although pure hydrogen is a gas, we find very little of it in our atmosphere. Hydrogen gas is so light that, uncombined, hydrogen will gain enough velocity from collisions with other gases that they will quickly be ejected from the atmosphere. On earth, hydrogen occurs chiefly in combination with oxygen in water, but it is also present in organic matter such as living plants, petroleum, coal, etc. It is present as the free element in the atmosphere, but only less than 1 ppm by volume. The lightest of all gases, hydrogen combines with other elements sometimes explosively to form compounds.
Quite apart from isotopes, it has been shown that under ordinary conditions hydrogen gas is a mixture of two kinds of molecules, known as ortho- and para-hydrogen, which differ from one another by the spins of their electrons and nuclei.
Normal hydrogen at room temperature contains 25% of the para form and 75% of the ortho form. The ortho form cannot be prepared in the pure state. Since the two forms differ in energy, the physical properties also differ. The melting and boiling points of parahydrogen are about 0.1°C lower than those of normal hydrogen.
See more information at the Hydrogen compound page.
Hydrogen is not toxic and is not radioactive, but it is highly flammable. Mixtures with air ignite over a broad concentration range, and the flame can be nearly invisible in daylight. Leaks disperse upward quickly but can accumulate under ceilings or in confined spaces. Compressed and liquid hydrogen add pressure, cryogenic, and embrittlement hazards. Oxygen displacement is possible in poorly ventilated areas.
Free hydrogen occurs naturally in small amounts from geological reactions, biological activity, and atmospheric chemistry, but it does not persist long near the surface. It is not known to bioaccumulate. Environmental effects depend strongly on how it is produced: steam methane reforming releases carbon dioxide unless captured, while electrolysis depends on the electricity source. Leaked hydrogen can affect atmospheric chemistry indirectly.
Hydrogen is produced at large scale, mainly from natural gas by steam methane reforming and from coal gasification in some regions; electrolysis is smaller but growing where low-carbon electricity is available. Major demand comes from ammonia, refining, methanol, and emerging fuel-cell and synthetic-fuel uses. Costs depend on energy prices, carbon policy, electrolyzer costs, transport, storage, and purity requirements. Because hydrogen is difficult to liquefy and has low volumetric energy density, infrastructure often shapes markets as much as production. Recycling is limited, but industrial off-gases are sometimes recovered and purified.
Hydrogen is estimated to make up more than 90% of all the atoms three quarters of the mass of the universe! This element is found in the stars, and plays an important part in powering the universe through both the proton-proton reaction and carbon-nitrogen cycle. Stellar hydrogen fusion processes release massive amounts of energy by combining hydrogens to form helium.
Production of hydrogen in the U.S. alone amounts to about 3 billion cubic feet per year. Hydrogen is prepared by
▸ steam on heated carbon,
▸ decomposition of certain hydrocarbons with heat,
▸ reaction of sodium or potassium hydroxide on aluminum
▸ electrolysis of water, or
▸ displacement from acids by certain metals.
Liquid hydrogen is important in cryogenics and in the study of superconductivity, as its melting point is only 20 degrees above absolute zero.
Tritium is readily produced in nuclear reactors and is used in the production of the hydrogen bomb.
Hydrogen is the primary component of Jupiter and the other gas giant planets. At some depth in the planet's interior the pressure is so great that solid molecular hydrogen is converted to solid metallic hydrogen.
In 1973, a group of Russian experimenters may have produced metallic hydrogen at a pressure of 2.8 Mbar. At the transition the density changed from 1.08 to 1.3 g/cm3. Earlier, in 1972, at Livermore, California, a group also reported on a similar experiment in which they observed a pressure-volume point centered at 2 Mbar. Predictions say that metallic hydrogen may be metastable; others have predicted it would be a superconductor at room temperature.
Most hydrogen formed in the first minutes after the Big Bang as protons combined with electrons later to make neutral atoms. It is the most abundant element in the universe and the main fuel of stars, where fusion converts hydrogen into helium. Hydrogen dominates gas giants, interstellar clouds, and much of the raw material from which new stars and planetary systems form.
- A hydrogen atom has no neutron in its most common isotope, protium.
- Liquid hydrogen is one of the coldest industrial liquids in regular use.
- Hydrogen gas is so light that Earth’s gravity cannot retain much of it over geological time.
- The Sun consumes hundreds of millions of tonnes of hydrogen each second through fusion.
- Hydrogen can behave like a metal only under extreme pressures, a state studied in giant planets and high-pressure laboratories.
Immagini
Proprietà
Fisiche
- Raggio atomico (empirico)
- 25 pm Confronta Raggio atomico (empirico) di tutti gli elementi →
- Raggio covalente
- 31 pm Confronta Raggio covalente di tutti gli elementi →
- Raggio di van der Waals
- 120 pm Confronta Raggio di van der Waals di tutti gli elementi →
- Densità
- 0,08988 kg/m³ Confronta Densità di tutti gli elementi →
- Volume molare
- 0,0141 L/mol
- Fase in condizioni STP
- Gas Confronta Fase in condizioni STP di tutti gli elementi →
- Punto di fusione
- -259,34 °C Confronta Punto di fusione di tutti gli elementi →
- Punto di ebollizione
- -252,87 °C Confronta Punto di ebollizione di tutti gli elementi →
- Conducibilità termica
- 0,181 W/(m·K) Confronta Conducibilità termica di tutti gli elementi →
- Capacità termica specifica
- 14,304 J/(g·K) Confronta Capacità termica specifica di tutti gli elementi →
- Capacità termica molare
- 28,836 J/(mol·K) Confronta Capacità termica molare di tutti gli elementi →
- Struttura cristallina
- Esagonale compatta Confronta Struttura cristallina di tutti gli elementi →
Chimiche
- Elettronegatività (Pauling)
- 2,2 Confronta Elettronegatività (Pauling) di tutti gli elementi →
- Elettronegatività (Allen)
- 2,3
- Affinità elettronica
- 0,75419 eV
- Energia di ionizzazione (1ª)
- 13,598435 eV Confronta Energia di ionizzazione (1ª) di tutti gli elementi →
- Stati di ossidazione
- −1, +1 Confronta Stati di ossidazione di tutti gli elementi →
- Elettroni di valenza
- 1 Confronta Elettroni di valenza di tutti gli elementi →
- Configurazione elettronica
- 1s1
Termodinamiche
- Punto triplo (temperatura)
- -259,3467 °C
- Punto triplo (pressione)
- 7041 Pa
- Punto critico (temperatura)
- -240,212 °C
- Punto critico (pressione)
- 1,2858e+6 Pa
- Calore di fusione
- 0,00121262 eV Confronta Calore di fusione di tutti gli elementi →
- Calore di vaporizzazione
- 0,00936933 eV Confronta Calore di vaporizzazione di tutti gli elementi →
- Calore di atomizzazione
- 2,259398 eV
- Entalpia di atomizzazione
- 2,259398 eV
Nucleari
- Protoni
- 1 Confronta Protoni di tutti gli elementi →
- Neutroni
- 0 Confronta Neutroni di tutti gli elementi →
- Isotopi noti
- 7 Confronta Isotopi noti di tutti gli elementi →
- Isotopi stabili
- 2 Confronta Isotopi stabili di tutti gli elementi →
- Isotopo più stabile
- H-1
- Anno della scoperta
- 1766
Abbondanza
- Abbondanza (crosta terrestre)
- 1400 mg/kg Confronta Abbondanza (crosta terrestre) di tutti gli elementi →
- Abbondanza (oceano)
- 1,08 × 105 mg/L Confronta Abbondanza (oceano) di tutti gli elementi →
Struttura cristallina
- Costante reticolare a
- 375 pm
Struttura elettronica
- Elettroni per guscio
- 1 Confronta Elettroni per guscio di tutti gli elementi →
Identificativi
- Numero CAS
- 1333-74-0 Confronta Numero CAS di tutti gli elementi →
- Simbolo di termine
- 2S1/2
- InChI
- InChI=1S/H
- Chiave InChI
- YZCKVEUIGOORGS-UHFFFAOYSA-N
Configurazione elettronica Misurato
H: 1s¹1s¹1s¹Modello atomico
Gli isotopi modificano il numero di neutroni, la massa e la stabilità — non la configurazione elettronica di un atomo neutro.
Modello atomico schematico, non in scala.
Impronta atomica
Spettro di emissione / assorbimento
Distribuzione isotopica
| Numero di massa | Massa atomica (u) | Abbondanza naturale | Emivita |
|---|---|---|---|
| 1 Stabile | 1,00782503223 ± 0,00000000009 | 99,9885% | Stabile |
| 2 Stabile | 2,01410177812 ± 0,00000000012 | 0,0115% | Stabile |
Fase / Stato
Motivo: 277,9 °C sopra il punto di ebollizione (-252,87 °C)
Schema non in scala
Punti di transizione di fase
Energie di transizione
Energia necessaria per fondere 1 mol al punto di fusione
Energia necessaria per vaporizzare 1 mol al punto di ebollizione
Densità
In condizioni standard
Stimata con la legge dei gas ideali alla T attuale
Avanzate
Spettri atomici
Righe disponibili ?
| Ione | Carica | Righe totali | Probabilità di transizione | Designazioni dei livelli |
|---|---|---|---|---|
| D I Isotopo | 0 | 364 | 161 | 341 |
| H I | 0 | 568 | 441 | 535 |
| T I Isotopo | 0 | 11 | 11 | 11 |
Livelli disponibili ?
| Ione | Carica | Livelli |
|---|---|---|
| D I Isotopo | 0 | 78 |
| H I | 0 | 106 |
| T I Isotopo | 0 | 10 |
Composti
Isotopi (2)
The ordinary isotope of hydrogen, H, is known as Protium, the other two isotopes are Deuterium (a proton and a neutron) and Tritium (a protron and two neutrons). Hydrogen is the only element whose isotopes have been given different names. Deuterium and Tritium are both used as fuel in nuclear fusion reactors. One atom of Deuterium is found in about 6000 ordinary hydrogen atoms.
| Numero di massa | Massa atomica (u) | Abbondanza naturale | Emivita | Modalità di decadimento | |
|---|---|---|---|---|---|
| 1 Stabile | 1,00782503223 ± 0,00000000009 | 99,9885% ± 0,0070% | Stabile | stable | |
| 2 Stabile | 2,01410177812 ± 0,00000000012 | 0,0115% ± 0,0070% | Stabile | stable |
Righe spettrali
| Lunghezza d'onda (nm) | Intensità | Stadio di ionizzazione | Tipo | Transizione | Accuratezza | Fonte | |
|---|---|---|---|---|---|---|---|
| 383.5355892 nm | N/D | H I | emission | 2p 2P* → 9d 2D | Misurata | NIST | |
| 383.5356424 nm | N/D | H I | emission | 2p 2P* → 9s 2S | Misurata | NIST | |
| 383.53587 nm | N/D | H I | emission | N/D | Misurata | NIST | |
| 383.5361082 nm | N/D | H I | emission | 2s 2S → 9p 2P* | Misurata | NIST | |
| 383.5361616 nm | N/D | H I | emission | 2s 2S → 9s 2S | Misurata | NIST | |
| 383.5361673 nm | N/D | H I | emission | 2s 2S → 9p 2P* | Misurata | NIST | |
| 383.53839 nm | N/D | H I | emission | N/D | Misurata | NIST | |
| 383.53909 nm | 30000 | H I | emission | 2 → 9 | Misurata | NIST | |
| 383.5409535 nm | N/D | H I | emission | 2p 2P* → 9d 2D | Misurata | NIST | |
| 383.54096 nm | N/D | H I | emission | N/D | Misurata | NIST | |
| 383.5409732 nm | N/D | H I | emission | 2p 2P* → 9d 2D | Misurata | NIST | |
| 383.5410263 nm | N/D | H I | emission | 2p 2P* → 9s 2S | Misurata | NIST | |
| 388.9019815 nm | N/D | H I | emission | 2p 2P* → 8d 2D | Misurata | NIST | |
| 388.9020595 nm | N/D | H I | emission | 2p 2P* → 8s 2S | Misurata | NIST | |
| 388.90227 nm | N/D | H I | emission | N/D | Misurata | NIST | |
| 388.9024865 nm | N/D | H I | emission | 2s 2S → 8d 2D | Misurata | NIST | |
| 388.9025152 nm | N/D | H I | emission | 2s 2S → 8p 2P* | Misurata | NIST | |
| 388.9025154 nm | N/D | H I | emission | 2s 2S → 8d 2D | Misurata | NIST | |
| 388.9025933 nm | N/D | H I | emission | 2s 2S → 8s 2S | Misurata | NIST | |
| 388.9026017 nm | N/D | H I | emission | 2s 2S → 8p 2P* | Misurata | NIST | |
| 388.90486 nm | N/D | H I | emission | N/D | Misurata | NIST | |
| 388.90557 nm | 70000 | H I | emission | 2 → 8 | Misurata | NIST | |
| 388.9074883 nm | N/D | H I | emission | 2p 2P* → 8d 2D | Misurata | NIST | |
| 388.90749 nm | N/D | H I | emission | N/D | Misurata | NIST | |
| 388.9075172 nm | N/D | H I | emission | 2p 2P* → 8d 2D | Misurata | NIST | |
| 388.9075951 nm | N/D | H I | emission | 2p 2P* → 8s 2S | Misurata | NIST | |
| 397.0041763 nm | N/D | H I | emission | 2p 2P* → 7d 2D | Misurata | NIST | |
| 397.0042976 nm | N/D | H I | emission | 2p 2P* → 7s 2S | Misurata | NIST | |
| 397.00448 nm | N/D | H I | emission | N/D | Misurata | NIST | |
| 397.0047325 nm | N/D | H I | emission | 2s 2S → 7p 2P* | Misurata | NIST | |
| 397.0048539 nm | N/D | H I | emission | 2s 2S → 7s 2S | Misurata | NIST | |
| 397.004867 nm | N/D | H I | emission | 2s 2S → 7p 2P* | Misurata | NIST | |
| 397.00719 nm | N/D | H I | emission | N/D | Misurata | NIST | |
| 397.00788 nm | 30000 | H I | emission | 2 → 7 | Misurata | NIST | |
| 397.0099002 nm | N/D | H I | emission | 2p 2P* → 7d 2D | Misurata | NIST | |
| 397.00991 nm | N/D | H I | emission | N/D | Misurata | NIST | |
| 397.009945 nm | N/D | H I | emission | 2p 2P* → 7d 2D | Misurata | NIST | |
| 397.0100663 nm | N/D | H I | emission | 2p 2P* → 7s 2S | Misurata | NIST | |
| 410.1702284 nm | N/D | H I | emission | 2p 2P* → 6d 2D | Misurata | NIST | |
| 410.1704339 nm | N/D | H I | emission | 2p 2P* → 6s 2S | Misurata | NIST | |
| 410.17056 nm | N/D | H I | emission | N/D | Misurata | NIST | |
| 410.1707462 nm | N/D | H I | emission | 2s 2S → 6d 2D | Misurata | NIST | |
| 410.1708218 nm | N/D | H I | emission | 2s 2S → 6p 2P* | Misurata | NIST | |
| 410.1710277 nm | N/D | H I | emission | 2s 2S → 6s 2S | Misurata | NIST | |
| 410.1710499 nm | N/D | H I | emission | 2s 2S → 6p 2P* | Misurata | NIST | |
| 410.17346 nm | N/D | H I | emission | N/D | Misurata | NIST | |
| 410.17415 nm | 70000 | H I | emission | 2 → 6 | Misurata | NIST | |
| 410.17631 nm | N/D | H I | emission | 2p 2P* → 6d 2D | Misurata | NIST | |
| 410.17632 nm | N/D | H I | emission | N/D | Misurata | NIST | |
| 410.176386 nm | N/D | H I | emission | 2p 2P* → 6d 2D | Misurata | NIST | |
| 410.1765915 nm | N/D | H I | emission | 2p 2P* → 6s 2S | Misurata | NIST | |
| 434.0426937 nm | N/D | H I | emission | 2p 2P* → 5d 2D | Misurata | NIST | |
| 434.04309 nm | N/D | H I | emission | N/D | Misurata | NIST | |
| 434.0430904 nm | N/D | H I | emission | 2p 2P* → 5s 2S | Misurata | NIST | |
| 434.0433568 nm | N/D | H I | emission | 2s 2S → 5p 2P* | Misurata | NIST | |
| 434.0437554 nm | N/D | H I | emission | 2s 2S → 5s 2S | Misurata | NIST | |
| 434.0437982 nm | N/D | H I | emission | 2s 2S → 5p 2P* | Misurata | NIST | |
| 434.04634 nm | N/D | H I | emission | N/D | Misurata | NIST | |
| 434.0471 nm | 90000 | H I | emission | 2 → 5 | Misurata | NIST | |
| 434.0494419 nm | N/D | H I | emission | 2p 2P* → 5d 2D | Misurata | NIST | |
| 434.04947 nm | N/D | H I | emission | N/D | Misurata | NIST | |
| 434.0495889 nm | N/D | H I | emission | 2p 2P* → 5d 2D | Misurata | NIST | |
| 434.0499857 nm | N/D | H I | emission | 2p 2P* → 5s 2S | Misurata | NIST | |
| 486.1278624 nm | N/D | H I | emission | 2p 2P* → 4d 2D | Misurata | NIST | |
| 486.1283363 nm | N/D | H I | emission | 2s 2S → 4d 2D | Misurata | NIST | |
| 486.12841 nm | N/D | H I | emission | N/D | Misurata | NIST | |
| 486.1286949 nm | N/D | H I | emission | 2s 2S → 4p 2P* | Misurata | NIST | |
| 486.128837 nm | N/D | H I | emission | 2p 2P* → 4s 2S | Misurata | NIST | |
| 486.1296711 nm | N/D | H I | emission | 2s 2S → 4s 2S | Misurata | NIST | |
| 486.1297761 nm | N/D | H I | emission | 2s 2S → 4p 2P* | Misurata | NIST | |
| 486.1325 nm | N/D | H I | emission | N/D | Misurata | NIST | |
| 486.1333 nm | 180000 | H I | emission | 2 → 4 | Misurata | NIST | |
| 486.1361516 nm | N/D | H I | emission | 2p 2P* → 4d 2D | Misurata | NIST | |
| 486.13622 nm | N/D | H I | emission | N/D | Misurata | NIST | |
| 486.1365118 nm | N/D | H I | emission | 2p 2P* → 4d 2D | Misurata | NIST | |
| 486.1374864 nm | N/D | H I | emission | 2p 2P* → 4s 2S | Misurata | NIST | |
| 656.27097 nm | N/D | H I | emission | 2p 2P* → 3d 2D | Misurata | NIST | |
| 656.2714 nm | N/D | H I | emission | N/D | Misurata | NIST | |
| 656.2722 nm | N/D | H I | emission | N/D | Misurata | NIST | |
| 656.272483 nm | N/D | H I | emission | 2s 2S → 3p 2P* | Misurata | NIST | |
| 656.275181 nm | N/D | H I | emission | 2p 2P* → 3s 2S | Misurata | NIST | |
| 656.276701 nm | N/D | H I | emission | 2s 2S → 3s 2S | Misurata | NIST | |
| 656.277 nm | N/D | H I | emission | N/D | Misurata | NIST | |
| 656.277153 nm | N/D | H I | emission | 2s 2S → 3p 2P* | Misurata | NIST | |
| 656.2795 nm | N/D | H I | emission | N/D | Misurata | NIST | |
| 656.2819 nm | 500000 | H I | emission | 2 → 3 | Misurata | NIST | |
| 656.285177 nm | N/D | H I | emission | 2p 2P* → 3d 2D | Misurata | NIST | |
| 656.28533 nm | N/D | H I | emission | N/D | Misurata | NIST | |
| 656.2854 nm | N/D | H I | emission | N/D | Misurata | NIST | |
| 656.286734 nm | N/D | H I | emission | 2p 2P* → 3d 2D | Misurata | NIST | |
| 656.290944 nm | N/D | H I | emission | 2p 2P* → 3s 2S | Misurata | NIST |
Proprietà estese
Raggi covalenti (dati estesi)
- Raggio covalente (Pyykkö)
- 32 pm
Raggi di van der Waals
- Bondi
- 120 pm
- Alvarez
- 120 pm
- UFF
- 288,6 pm
- MM3
- 162 pm
- Dreiding
- 319,5 pm
- Rowland–Taylor
- 110 pm
Raggi atomici e metallici
- Raggio atomico (Rahm)
- 154 pm
- Raggio metallico (C12)
- 78 pm
Scale di numerazione
- Mendeleev
- 105
- Pettifor
- 103
- Glawe
- 103
Scale di elettronegatività
- Ghosh
- 0
- Miedema
- 5
- Gunnarsson–Lundqvist
- 6
- Robles–Bartolotti
- 5
Polarizzabilità e dispersione
- Polarizzabilità dipolare
- 4,5071 a.u.
- Polarizzabilità dipolare (inc.)
- 0 a.u.
- C₆
- 6,499 Ha·Bohr6
- C₆ (Gould–Bučko)
- 6,51 Ha·Bohr6
Parametri di Miedema
- Volume molare di Miedema
- 1,7 cm3/mol
- Densità elettronica di Miedema
- 3
Transizioni di fase e allotropi
| Punto di fusione | 13,99 K |
| Punto di ebollizione | 20,27 K |
| Punto critico (temperatura) | 32,94 K |
| Punto critico (pressione) | 1,29 MPa |
| Punto triplo (temperatura) | 13,8 K |
| Punto triplo (pressione) | 7,04 kPa |
Categorie degli stati di ossidazione
Dati di riferimento avanzati
Costanti di schermaggio (1)
| n | Orbitale | σ |
|---|---|---|
| 1 | s | 0 |
Dettaglio dei raggi cristallini (2)
| Carica | CN | Spin | rcrystal (pm) | Origine |
|---|---|---|---|---|
| 1 | I | -24 | ||
| 1 | II | -4 |
Modalità di decadimento degli isotopi (6)
| Isotopo | Modalità | Intensità |
|---|---|---|
| 3 | B- | 100% |
| 4 | n | 100% |
| 5 | 2n | 100% |
| 6 | n | — |
| 6 | 3n | — |
| 7 | 2n | — |
Fattori di diffusione dei raggi X (501)
| Energia (eV) | f₁ | f₂ |
|---|---|---|
| 10 | — | 0 |
| 10,1617 | — | 0 |
| 10,3261 | — | 0 |
| 10,4931 | — | 0 |
| 10,6628 | — | 0 |
| 10,8353 | — | 0 |
| 11,0106 | — | 0 |
| 11,1886 | — | 0 |
| 11,3696 | — | 0 |
| 11,5535 | — | 0 |
Dati aggiuntivi
Estimated Crustal Abundance
The estimated element abundance in the earth's crust.
1.40×103 milligrams per kilogram
Riferimenti (1)
- [5] Hydrogen https://education.jlab.org/itselemental/ele001.html
Estimated Oceanic Abundance
The estimated element abundance in the earth's oceans.
1.08×105 milligrams per liter
Riferimenti (1)
- [5] Hydrogen https://education.jlab.org/itselemental/ele001.html
Sources
Sources of this element.
Hydrogen is estimated to make up more than 90% of all the atoms three quarters of the mass of the universe! This element is found in the stars, and plays an important part in powering the universe through both the proton-proton reaction and carbon-nitrogen cycle. Stellar hydrogen fusion processes release massive amounts of energy by combining hydrogens to form helium.
Production of hydrogen in the U.S. alone amounts to about 3 billion cubic feet per year. Hydrogen is prepared by
▸ steam on heated carbon,
▸ decomposition of certain hydrocarbons with heat,
▸ reaction of sodium or potassium hydroxide on aluminum
▸ electrolysis of water, or
▸ displacement from acids by certain metals.
Liquid hydrogen is important in cryogenics and in the study of superconductivity, as its melting point is only 20 degrees above absolute zero.
Tritium is readily produced in nuclear reactors and is used in the production of the hydrogen bomb.
Hydrogen is the primary component of Jupiter and the other gas giant planets. At some depth in the planet's interior the pressure is so great that solid molecular hydrogen is converted to solid metallic hydrogen.
In 1973, a group of Russian experimenters may have produced metallic hydrogen at a pressure of 2.8 Mbar. At the transition the density changed from 1.08 to 1.3 g/cm3. Earlier, in 1972, at Livermore, California, a group also reported on a similar experiment in which they observed a pressure-volume point centered at 2 Mbar. Predictions say that metallic hydrogen may be metastable; others have predicted it would be a superconductor at room temperature.
Riferimenti (1)
- [6] Hydrogen https://periodic.lanl.gov/1.shtml
Isotopes in Forensic Science and Anthropology
Information on the use of this element's isotopes in forensic science and anthropology.
Measurements of relative 2H abundances are used to determine the breeding grounds of many species of migrant songbirds. These species of songbirds only grow their feathers before migration, and they grow them on or close to their breeding grounds. Therefore, the isotopic composition of a bird’s feathers correlates to the isotopic composition of the growing season’s precipitation [18] Z. D. Sharp, V. Atudorei, H. O. Panarello, J. Fernández, C. Douthitt. J. Archaeolog. Sci.30, 1709 (2003)., [19] K. A. Hobson. Oecologia120, 314 (1999)., [20] K. A. Hobson, L. I. Wassenaar. Oecologia.109, 142 (1996)..
Measurements of relative 2H abundances of human hair samples collected at archeological sites are used to determine the geographic region in which a subject lived based on the hydrogen isotopic composition of the water they drank. This is possible because hair stores a daily record of the hydrogen isotopic composition of intake water, which correlates to local meteoric water [18] Z. D. Sharp, V. Atudorei, H. O. Panarello, J. Fernández, C. Douthitt. J. Archaeolog. Sci.30, 1709 (2003)., [21] T. B. Coplen, H. Qi. Forensic Sci. Int.266, 222 (2016)..
Riferimenti (5)
- [18] Z. D. Sharp, V. Atudorei, H. O. Panarello, J. Fernández, C. Douthitt. J. Archaeolog. Sci.30, 1709 (2003).
- [19] K. A. Hobson. Oecologia120, 314 (1999).
- [20] K. A. Hobson, L. I. Wassenaar. Oecologia.109, 142 (1996).
- [21] T. B. Coplen, H. Qi. Forensic Sci. Int.266, 222 (2016).
- [4] IUPAC Periodic Table of the Elements and Isotopes (IPTEI) https://doi.org/10.1515/pac-2015-0703
Riferimenti
(9)
Data deposited in or computed by PubChem
The half-life and atomic mass data was provided by the Atomic Mass Data Center at the International Atomic Energy Agency.
Element data are cited from the Atomic weights of the elements (an IUPAC Technical Report). The IUPAC periodic table of elements can be found at https://iupac.org/what-we-do/periodic-table-of-elements/. Additional information can be found within IUPAC publication doi:10.1515/pac-2015-0703 Copyright © 2020 International Union of Pure and Applied Chemistry.
The information are cited from Pure Appl. Chem. 2018; 90(12): 1833-2092, https://doi.org/10.1515/pac-2015-0703.
Thomas Jefferson National Accelerator Facility (Jefferson Lab) is one of 17 national laboratories funded by the U.S. Department of Energy. The lab's primary mission is to conduct basic research of the atom's nucleus using the lab's unique particle accelerator, known as the Continuous Electron Beam Accelerator Facility (CEBAF). For more information visit https://www.jlab.org/
The periodic table at the LANL (Los Alamos National Laboratory) contains basic element information together with the history, source, properties, use, handling and more. The provenance data may be found from the link under the source name.
The periodic table contains NIST's critically-evaluated data on atomic properties of the elements. The provenance data that include data for atomic spectroscopy, X-ray and gamma ray, radiation dosimetry, nuclear physics, and condensed matter physics may be found from the link under the source name. Ref: https://www.nist.gov/pml/atomic-spectra-database
This section provides all form of data related to element Hydrogen.
The element property data was retrieved from publications.