Hydrogen iodide

Hydrogen iodide
Hydrogen iodide
Hydrogen iodide
Names
IUPAC name
Hydrogen iodide
Systematic IUPAC name
Iodane
Other names
Hydroiodic acid (aqueous solution)
Iodine hydride
Identifiers
3D model (JSmol)
ChEBI
ChemSpider
ECHA InfoCard 100.030.087
EC Number
  • 233-109-9
KEGG
RTECS number
  • MW3760000
UNII
UN number 1787 2197
  • I
Properties
HI
Molar mass 127.91 g·mol−1
Appearance Colorless gas
Odor acrid
Density 2.85 g/mL (−47 °C)
Melting point −50.80 °C (−59.44 °F; 222.35 K)
Boiling point −35.36 °C (−31.65 °F; 237.79 K)
approximately 245 g/100 ml
Acidity (pKa) −10 (in water, estimate);[1] −9.5 (±1.0)[2]

2.8 (in acetonitrile)[3]

Conjugate acid Iodonium
Conjugate base Iodide
1.466 (16 °C)[4]
Structure
Terminus
0.38 D
Thermochemistry
Standard molar
entropy So298 		206.6 J·mol−1·K−1
Specific heat capacity, C 29.2 J·mol−1·K−1
Hazards
Main hazards Toxic, corrosive, harmful and irritant
NFPA 704

0
3
1
 
Flash point Non-flammable
Related compounds
Other anions {{{value}}}
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
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Infobox references

Hydrogen iodide (HI) is a chemical compound. Its chemical formula is HI. It is a colorless odorous gas. It reacts with oxygen to make iodine and water. It can be made by reducing iodine with hydrazine. It can also be made by reacting iodides with non-oxidizing acids such as phosphoric acid. It can also be made by reacting hydrogen sulfide with iodine. Very pure hydrogen iodide can be made by combining hydrogen and iodine, but this is very slow. It will break down if exposed to air. It can be used to make illegal drugs and various chemical compounds of iodine. It dissolves in water to produce hydroiodic acid. Hydroiodic acid is a strong acid that is used to make iodides.

References

  1. ↑ Bell, R.P. The Proton in Chemistry. 2nd ed., Cornell University Press, Ithaca, NY, 1973.
  2. ↑ Trummal, A.; Lipping, L.; Kaljurand, I.; Koppel, I. A.; Leito, I. "Acidity of Strong Acids in Water and Dimethyl Sulfoxide" J. Phys. Chem. A. 2016, 120, 3663-3669. doi:10.1021/acs.jpca.6b02253
  3. ↑ Raamat, E.; Kaupmees, K.; Ovsjannikov, G.; Trummal, A.; Kütt, A.; Saame, J.; Koppel, I.; Kaljurand, I.; Lipping, L.; Rodima, T.; Pihl, V.; Koppel, I. A.; Leito, I. "Acidities of strong neutral Brønsted acids in different media." J. Phys. Org. Chem. 2013, 26, 162-170. doi:10.1002/poc.2946
  4. ↑ CRC handbook of chemistry and physics: a ready-reference book of chemical and physical data. William M. Haynes, David R. Lide, Thomas J. Bruno (2016-2017, 97th ed.). Boca Raton, Florida. 2016. ISBN 978-1-4987-5428-6. OCLC 930681942.{{cite book}}: CS1 maint: location missing publisher (link) CS1 maint: others (link)

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