Hydrogen

An inorganic compound, H2, 2.016 g/mol. Boiling point -423 °F at 760 mmHg, melting point -434 °F, as published. Appears in 1 documented reaction.

verified recordInorganic compound6 measured properties1 documented reactions

Identifiers

Molecular formula: H₂
Molecular weight: 2.016 g/mol
Exact mass: 2.01565 g/mol
IUPAC name: molecular hydrogen
SMILES: [H][H]
InChI: InChI=1S/H2/h1H
InChIKey: UFHFLCQGNIYNRP-UHFFFAOYSA-N

Open in ReactionLens Use in reaction prediction

Measured properties

Published measurements, each with its source. Two readings of one property are both shown, in the units each used.

Boiling Point: -423 °F at 760 mmHg (USCG, 1999)measured · CAMEO Chemicals; -423 °F at 760 mmHg (USCG, 1999)measured · CAMEO Chemicals
Melting Point: -434 °F (USCG, 1999)measured · CAMEO Chemicals; -434 °F (USCG, 1999)measured · CAMEO Chemicals
Density: 0.071 at -423.4 °F (USCG, 1999) - Less dense than water; will floatmeasured · CAMEO Chemicals; 0.071 at -423.4 °F (USCG, 1999) - Less dense than water; will floatmeasured · CAMEO Chemicals
Solubility: In water, 1.62 mg/L at 21 °Cmeasured · Hazardous Substances Data Bank (HSDB); Soluble in about 50 volumes of water at 0 degCmeasured · Hazardous Substances Data Bank (HSDB)
Vapor Pressure: 1.24X10+6 mm Hg at 25 °Cmeasured · Hazardous Substances Data Bank (HSDB); Vapor pressure, kPa at 25 °C: 165320measured · ILO-WHO International Chemical Safety Cards (ICSCs)
Flash Point: Flammable gasmeasured · ILO-WHO International Chemical Safety Cards (ICSCs)

Calculated properties

Derived from the structure, not from a sample; kept apart from the measurements above.

Molecular weight: 2.016 g/molcalculated · reference compound database; Average mass of one molecule, from reference compound database.
Exact mass: 2.0156500638 Dacalculated · reference compound database; Mass of the most common isotopic form.
XLogP3: 0calculated · reference compound database; Estimated oil/water partition, computed by reference compound database.
Polar surface area: 0 Å²calculated · reference compound database; Polar surface area as computed by reference compound database.
Complexity: 0calculated · reference compound database; A rough measure of how intricate the structure is.
H-bond donors: 0calculated · reference compound database
H-bond acceptors: 0calculated · reference compound database
logP: 0.246calculated · chemistry engine; Estimated preference for oil over water. Higher means more oil-like.
Topological polar surface area: 0 Å²calculated · chemistry engine; Surface area from polar atoms; relates to how easily a molecule crosses membranes.
H-bond donors: 0calculated · chemistry engine; Atoms that can donate a hydrogen bond.
H-bond acceptors: 0calculated · chemistry engine; Atoms that can accept a hydrogen bond.
Rotatable bonds: 0calculated · chemistry engine; Single bonds the molecule can freely twist around.
Molar refractivity: 2.114 cm³/molcalculated · chemistry engine; Relates to the molecule's polarisability.
Fraction sp³ carbons: 0calculated · chemistry engine; Share of carbon atoms with tetrahedral bonding.
QED drug-likeness: 0.3462calculated · chemistry engine; Quantitative estimate of drug-likeness (0–1).

What it is made of

Elements

H Hydrogen2 atoms · 100.0% by mass

Percentages are of the molecular weight above, worked out the same way the molar mass calculator does it.

Structure

Heavy atoms, hydrogen excluded: 0
Total atoms, hydrogen included: 2
Rings: 0
Aromatic rings: 0
Stereocentres: 0
Formal charge: 0

The molecule in three dimensions

Rotate and inspect the atoms. Loaded only when you ask, so the page stays light.

The drawing above is a diagram of what is bonded to what. A molecule is not flat, and the model here is one low-energy shape generated from the connectivity — useful for seeing which groups can reach each other, and not a measured structure. A real sample is a population of conformations, interconverting.

Reactions it appears in

1 documented reaction involves Hydrogen, each with a written procedure and a source, and all of them are combustion. A few are shown.

Formation of water from hydrogen and oxygen

Combustion · as a reactant

A recorded experiment with its conditions, its yield where one was published, and a link to the source.

All 1 combustion records

Other names for it

The systematic name on this record is molecular hydrogen.

The sources also call it Molecular hydrogen, Dihydrogen, hydrogen-1, DTXSID9029643, 7YNJ3PO35Z, CHEBI:18276, Hydrogen atoms, RefChem:389053, DTXCID00196437, H, Protium.

Structurally related

Nothing structurally close to Hydrogen has a page here yet.

Seen alongside it in reaction records

Molecules that appear in the same recorded reactions as Hydrogen. This says nothing about structure: most of them are the bases, solvents, ligands and catalysts the chemistry needed, and they are here because somebody put them in the same flask.

1,4-Dioxane

used as a reactant

C₄H₈O₂, 88.106 g/mol.

Where these values came from

reference compound database783
compound record
chemistry engine
structure perception

compound record.

What this page does not claim

Identifiers are copied from the source record, measured values are reported as published, and calculated values are marked as calculated. Nothing here is a hazard, purity or handling assessment — how the library is checked.