Hydrogen iodide

A simple hydride, HI, 127.912 g/mol. Boiling point -35.1 °C at 760 mm Hg, melting point -50.8 °C, as published.

verified recordSimple hydride5 measured properties

Identifiers

Molecular formula: HI
Molecular weight: 127.912 g/mol
Exact mass: 127.912298 g/mol
IUPAC name: iodane
SMILES: I
InChI: InChI=1S/HI/h1H
InChIKey: XMBWDFGMSWQBCA-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: -35.1 °C at 760 mm Hgmeasured · Hazardous Substances Data Bank (HSDB); Boiling point: -18.9 °C at 2 atm; 7.3 °C at 5 atm; 32.0 at 10 atm; 127.5 °C at 60 atm; decomposed by light; specific heat: 0.0545 cal/ g °C at 25 °C; forms an azeotrope with water /Hydrogen iodide/measured · Hazardous Substances Data Bank (HSDB)
Melting Point: -50.8 °Cmeasured · Hazardous Substances Data Bank (HSDB); -50.8 °Cmeasured · ILO-WHO International Chemical Safety Cards (ICSCs)
Density: 5.66 g/L at 0 °C; 5.23 g/L at 25 °Cmeasured · Hazardous Substances Data Bank (HSDB); A solution of hydrogen iodide in water; marketed in various concentrations; 57% HI density: 1.7; 47% HI, density: 1.5; 10% HI, density: 1.1; colorless when freshly made, but rapidly turns yellowish ormeasured · Hazardous Substances Data Bank (HSDB)
Solubility: Extremely soluble in water; 234 g/100 g water at 10 °C; 900 g/100 g water at 0 °Cmeasured · Hazardous Substances Data Bank (HSDB); Solubility in water, g/100ml at 20 °C: 42 (freely soluble)measured · ILO-WHO International Chemical Safety Cards (ICSCs)
Vapor Pressure: 5,938 mm Hg at 25 °Cmeasured · Hazardous Substances Data Bank (HSDB); Vapor pressure, kPa at 20 °C: 733measured · 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: 127.9124 g/molcalculated · reference compound database; Average mass of one molecule, from reference compound database.
Exact mass: 127.9123 Dacalculated · reference compound database; Mass of the most common isotopic form.
XLogP3: 0.9calculated · 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: 1calculated · reference compound database
H-bond acceptors: 0calculated · reference compound database
logP: 0.618calculated · 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: 15.415 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: 0.4191calculated · chemistry engine; Quantitative estimate of drug-likeness (0–1).

What it is made of

Elements

I Iodine1 atom · 99.2% by mass
H Hydrogen1 atom · 0.8% 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: 1
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

No documented reaction with a written procedure and a source involves Hydrogen iodide yet.

Other names for it

The systematic name on this record is iodane.

The sources also call it Hydriodic acid, Hydroiodic acid, iodane, Hyriodic acid, Acido yodhidrico, Acide iodhydrique, Hydrogen iodide (HI), Anhydrous hydriodic acid, Hydrogen iodide, anhydrous, Iodure d'hydrogene anhydre, Yoduro de hidrogeno anhidro.

Structurally related

Nothing structurally close to Hydrogen iodide has a page here yet.

Seen alongside it in reaction records

Molecules that appear in the same recorded reactions as Hydrogen iodide. 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-(2-(isopropoxy)ethyl)-1H-benzimidazol-2-yl)(1-(t-butoxycarbonyl)piperidin-4-yl)amine

used as a reactant

C₂₂H₃₄N₄O₃, 402.539 g/mol.

1,1,3,3-Tetramethyl-2-(2-morpholin-4-ylphenyl)guanidine

formed as a product

C₁₅H₂₄N₄O, 276.384 g/mol.

(+/-)-7-[1-[(Iodoacetyl)oxy]propyl]-8-methylindolizino[1,2-b]quinolin-9(11H)-one

used as a reactant

C₂₁H₁₉IN₂O₃, 474.298 g/mol.

1,2-Dimethyl-3-[(4-methylphenyl)methyl]guanidine

formed as a product

C₁₁H₁₇N₃, 191.278 g/mol.

Where these values came from

reference compound database24841
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.