Tetrachloroiodic acid

Tetrachloroiodic acid
Identifiers
3D model (JSmol)
  • InChI=1S/Cl4I/c1-5(2,3)4/q-1/p+1
    Key: VEFRWHPHQIYAIZ-UHFFFAOYSA-O
  • [H+].[Cl-][I3+]([Cl-])([Cl-])[Cl-]
Properties
HICl4
Appearance Orange crystals (hydrate)
Melting point 19 °C (66 °F; 292 K) (hydrate)
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
Infobox references

Tetrachloroiodic acid is an inorganic compound with the formula HICl4, which acts the only example of a stable acid derived from a polyhalide. An orange crystalline tetrahydrate is known. No anhydrous tetrachloroiodic acid is known to exist; rather, it is isolated as hydronium salts of the tetrachloroiodate anion. It is unstable in air.[1]

Synthesis

Tetrachloroiodic acid may be formed by dissolution of iodine trichloride in concentrated hydrochloric acid:[2]

ICl3 + HCl → HICl4

Tetrachloroiodic acid may also be made by adding hydrochloric acid to iodates or periodates, or by passing chlorine through a solution of iodine in concentrated hydrochloric acid,

I2 + 3 Cl2 + 2 HCl + 4 H2O → 2 HICl4

although it quickly decomposes into iodine and iodate when introduced into less acidic conditions.

Physical properties

Tetrachloroiodic acid forms a crystal hydrate which has orange crystals that are unstable in air and melt by dissolving in their own water of crystallization at 19 °C. Crystals of HICl4·4H2O contain square planar tetrachloroiodate anions associated with various hydronium cations such as H5O2+,[2] showing structural similarities to the hydrates of other chloride-based inorganic acids, most notably HAuCl4·4H2O.

Hydrates of the sodium and potassium salts of the tetrachloroiodate anion (ICl4-) have been isolated, along with tetrachloroiodates of various alkaloids.[2][3]

See also

References

  1. ^ Tetrachloroiodic (3) acid HICl4x4H2O
  2. ^ a b c Bateman, Richard J.; Bateman, Linda R. (1972). "Solid-state structure, nuclear quadrupole resonance spectrum, and the resultant symmetry implications for tetrachloroiodic acid tetrahydrate". Journal of the American Chemical Society. 94 (4): 1130–1134. Bibcode:1972JAChS..94.1130B. doi:10.1021/ja00759a017.
  3. ^ Chattaway, F. D., & Parkes, G. D. (1930). CXXIV.—Tetrachloroiodides of the alkaloids. Journal of the Chemical Society (Resumed), 0(0), 1003–1005. https://doi.org/10.1039/jr9300001003


This article is issued from Wikipedia. The text is available under Creative Commons Attribution-Share Alike 4.0 unless otherwise noted. Additional terms may apply for the media files.