CHEBI:18276 - dihydrogen

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ChEBI Name dihydrogen
ChEBI ID CHEBI:18276
Definition An elemental molecule consisting of two hydrogens joined by a single bond.
Stars This entity has been manually annotated by the ChEBI Team.
Secondary ChEBI IDs CHEBI:5785, CHEBI:13350, CHEBI:25363
Supplier Information ChemicalBook:CB7686195, ChemicalBook:CB4217972
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Hydrogen is a chemical element; it has symbol H and atomic number 1. It is the lightest element and, at standard conditions, is a gas of diatomic molecules with the formula H2, sometimes called dihydrogen, but more commonly called hydrogen gas, molecular hydrogen or simply hydrogen. It is colorless, odorless, non-toxic, and highly combustible. Constituting about 75% of all normal matter, hydrogen is the most abundant chemical element in the universe. Stars, including the Sun, mainly consist of hydrogen in a plasma state, while on Earth, hydrogen is found in water, organic compounds, as dihydrogen, and in other molecular forms. The most common isotope of hydrogen (protium, 1H) consists of one proton, one electron, and no neutrons. In the early universe, the formation of hydrogen's protons occurred in the first second after the Big Bang; neutral hydrogen atoms only formed about 370,000 years later during the recombination epoch as the universe cooled and plasma had cooled enough for electrons to remain bound to protons. Hydrogen, typically nonmetallic except under extreme pressure, readily forms covalent bonds with most nonmetals, contributing to the formation of compounds like water and various organic substances. Its role is crucial in acid-base reactions, which mainly involve proton exchange among soluble molecules. In ionic compounds, hydrogen can take the form of either a negatively charged anion, where it is known as hydride, or as a positively charged cation, H+. The cation, usually just a proton (symbol p), exhibits specific behavior in aqueous solutions and in ionic compounds involves screening of its electric charge by surrounding polar molecules or anions. Hydrogen's unique position as the only neutral atom for which the Schrödinger equation can be directly solved, has significantly contributed to the foundational principles of quantum mechanics through the exploration of its energetics and chemical bonding. Hydrogen gas was first produced artificially in the early 16th century by reacting acids with metals. Henry Cavendish, in 1766–81, identified hydrogen gas as a distinct substance and discovered its property of producing water when burned; hence its name means "water-former" in Greek. Most hydrogen production occurs through steam reforming of natural gas; a smaller portion comes from energy-intensive methods such as the electrolysis of water. Its main industrial uses include fossil fuel processing, such as hydrocracking, and ammonia production, with emerging uses in fuel cells for electricity generation and as a heat source. When used in fuel cells, hydrogen's only emission at point of use is water vapor, though combustion can produce nitrogen oxides. Hydrogen's interaction with metals may cause embrittlement.
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Formula H2
Net Charge 0
Average Mass 2.01588
Monoisotopic Mass 2.01565
InChI InChI=1S/H2/h1H
InChIKey UFHFLCQGNIYNRP-UHFFFAOYSA-N
SMILES [H][H]
Metabolite of Species Details
Homo sapiens (NCBI:txid9606) See: DOI
Roles Classification
Chemical Role(s): antioxidant
A substance that opposes oxidation or inhibits reactions brought about by dioxygen or peroxides.
electron donor
A molecular entity that can transfer an electron to another molecular entity.
Biological Role(s): human metabolite
Any mammalian metabolite produced during a metabolic reaction in humans (Homo sapiens).
food packaging gas
A food additive that is a (generally inert) gas which is used to envelop foodstuffs during packing and so protect them from unwanted chemical reactions such as food spoilage or oxidation during subsequent transport and storage. The term includes propellant gases, used to expel foods from a container.
Application(s): fuel
An energy-rich substance that can be transformed with release of usable energy.
food packaging gas
A food additive that is a (generally inert) gas which is used to envelop foodstuffs during packing and so protect them from unwanted chemical reactions such as food spoilage or oxidation during subsequent transport and storage. The term includes propellant gases, used to expel foods from a container.
View more via ChEBI Ontology
ChEBI Ontology
Outgoing dihydrogen (CHEBI:18276) has role antioxidant (CHEBI:22586)
dihydrogen (CHEBI:18276) has role electron donor (CHEBI:15022)
dihydrogen (CHEBI:18276) has role food packaging gas (CHEBI:77974)
dihydrogen (CHEBI:18276) has role fuel (CHEBI:33292)
dihydrogen (CHEBI:18276) has role human metabolite (CHEBI:77746)
dihydrogen (CHEBI:18276) is a elemental hydrogen (CHEBI:33260)
dihydrogen (CHEBI:18276) is a elemental molecule (CHEBI:25362)
dihydrogen (CHEBI:18276) is a gas molecular entity (CHEBI:138675)
Incoming dideuterium (CHEBI:29294) is a dihydrogen (CHEBI:18276)
diprotium (CHEBI:29299) is a dihydrogen (CHEBI:18276)
ditritium (CHEBI:29298) is a dihydrogen (CHEBI:18276)
H group (CHEBI:64428) is substituent group from dihydrogen (CHEBI:18276)
IUPAC Name
dihydrogen
Synonyms Sources
dihydrogen ChEBI
E 949 ChEBI
E-949 ChEBI
E949 ChEBI
H2 KEGG COMPOUND
H2 IUPAC
H2 UniProt
Hydrogen KEGG COMPOUND
molecular hydrogen ChEBI
Manual Xrefs Databases
748 MolBase
C00282 KEGG COMPOUND
HMDB0001362 HMDB
Hydrogen Wikipedia
HYDROGEN-MOLECULE MetaCyc
View more database links
Registry Numbers Types Sources
1333-74-0 CAS Registry Number KEGG COMPOUND
1333-74-0 CAS Registry Number ChemIDplus
1333-74-0 CAS Registry Number NIST Chemistry WebBook
3 Gmelin Registry Number Gmelin
3587189 Reaxys Registry Number Reaxys
Citations
Fernández C, Carracedo B, Martínez EJ, Gómez X, Morán A (2014)
Application of a packed bed reactor for the production of hydrogen from cheese whey permeate: effect of organic loading rate.
Journal of environmental science and health. Part A, Toxic/hazardous substances & environmental engineering 49, 210-217 [PubMed:24171421]
[show Abstract]
Zheng J, Liu K, Kang Z, Cai J, Liu W, Xu W, Li R, Tao H, Zhang JH, Sun X (2010)
Saturated hydrogen saline protects the lung against oxygen toxicity.
Undersea & hyperbaric medicine : journal of the Undersea and Hyperbaric Medical Society, Inc 37, 185-192 [PubMed:20568549]
[show Abstract]
Youngblood WJ, Lee SH, Maeda K, Mallouk TE (2009)
Visible light water splitting using dye-sensitized oxide semiconductors.
Accounts of chemical research 42, 1966-1973 [PubMed:19905000]
[show Abstract]
Dismukes GC, Brimblecombe R, Felton GA, Pryadun RS, Sheats JE, Spiccia L, Swiegers GF (2009)
Development of bioinspired Mn4O4-cubane water oxidation catalysts: lessons from photosynthesis.
Accounts of chemical research 42, 1935-1943 [PubMed:19908827]
[show Abstract]
Sato Y, Kajiyama S, Amano A, Kondo Y, Sasaki T, Handa S, Takahashi R, Fukui M, Hasegawa G, Nakamura N, Fujinawa H, Mori T, Ohta M, Obayashi H, Maruyama N, Ishigami A (2008)
Hydrogen-rich pure water prevents superoxide formation in brain slices of vitamin C-depleted SMP30/GNL knockout mice.
Biochemical and biophysical research communications 375, 346-350 [PubMed:18706888]
[show Abstract]
Sung Y, Ritalahti KM, Apkarian RP, Löffler FE (2006)
Quantitative PCR confirms purity of strain GT, a novel trichloroethene-to-ethene-respiring Dehalococcoides isolate.
Applied and environmental microbiology 72, 1980-1987 [PubMed:16517646]
[show Abstract]
Nerenberg R, Rittmann BE (2004)
Hydrogen-based, hollow-fiber membrane biofilm reactor for reduction of perchlorate and other oxidized contaminants.
Water science and technology : a journal of the International Association on Water Pollution Research 49, 223-230 [PubMed:15303745]
[show Abstract]
Last Modified
13 October 2017