Diphosphorus tetraiodide

Source: Wikipedia, the free encyclopedia.
Diphosphorus tetraiodide
Ball-and-stick model of the diphosphorus tetraiodide molecule
Names
IUPAC name
Diphosphorus tetraiodide
Preferred IUPAC name
Tetraiododiphosphane
Other names
Phosphorus(II) iodide
Identifiers
3D model (
JSmol
)
ChemSpider
ECHA InfoCard
 100.033.301 Edit this at Wikidata
EC Number
  • 236-646-7
  • InChI=1S/I4P2/c1-5(2)6(3)4
    Key: YXXQTQYRRHHWFL-UHFFFAOYSA-N
  • P(P(I)I)(I)I
Properties
P2I4
Molar mass 569.57 g/mol
Appearance Orange crystalline solid
Melting point 125.5 °C (257.9 °F; 398.6 K)
Boiling point Decomposes
Decomposes
Hazards
GHS labelling:
GHS05: Corrosive
Danger
H314
P260, P264, P280, P301+P330+P331, P303+P361+P353, P304+P340, P305+P351+P338, P310, P321, P363, P405, P501
Flash point Non-flammable
Related compounds
Other anions
 Diphosphorus tetrafluoride
Diphosphorus tetrachloride
Diphosphorus tetrabromide
Other cations
 diarsenic tetraiodide
Related Binary Phosphorus halides
 phosphorus triiodide
Related compounds
diphosphines
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
checkY verify (what is checkY☒N ?)

Diphosphorus tetraiodide is an orange crystalline solid with the formula P2I4. It has been used as a reducing agent in organic chemistry. It is a rare example of a compound with phosphorus in the +2 oxidation state, and can be classified as a subhalide of phosphorus. It is the most stable of the diphosphorus tetrahalides.[1]

Synthesis and structure

Diphosphorus tetraiodide is easily generated by the disproportionation of phosphorus triiodide in dry ether:

2 PI3 → P2I4 + I2

It can also be obtained by treating phosphorus trichloride and potassium iodide in anhydrous conditions.[2]

Another synthesis route involves combining phosphonium iodide with iodine in a solution of carbon disulfide. An advantage of this route is that the resulting product is virtually free of impurities.[3]

2PH4I + 5I2 → P2I4 + 8HI

The compound adopts a centrosymmetric structure with a P-P bond of 2.230 Å.[4]

Reactions

Inorganic chemistry

Diphosphorus tetraiodide reacts with bromine to form mixtures PI3−xBrx. With sulfur, it is oxidized to P2S2I4, retaining the P-P bond.[1] It reacts with elemental phosphorus and water to make phosphonium iodide, which is collected via sublimation at 80 °C.[3]

Organic chemistry

Diphosphorus tetraiodide is used in organic synthesis mainly as a deoxygenating agent.

bromides.[7]

As foreshadowed by the work of Bertholet in 1855, diphosphorus tetraiodide can convert

alkenes.[5][8] This reaction is known as the Kuhn–Winterstein reaction, after the chemists who applied it to the production of polyene chromophores.[5][9]

References

  1. ^
    ISBN 978-0-08-037941-8
    .
  2. doi:10.1055/s-1978-24936
    .
  3. ^ a b Brown, Glenn Halstead (1951). Reactions of phosphine and phosphonium iodide (PhD). Iowa State College. Retrieved 5 Oct 2020.
  4. doi:10.1107/S0108270195012510
    .
  5. ^
    ISBN 978-0471936237
    .
  6. doi:10.1246/cl.1984.2129
    .
  7. doi:10.1016/j.tetlet.2007.04.137
    .
  8. doi:10.1002/hlca.19280110107
    .
  9. doi:10.1002/jlac.19656840106
    .
Retrieved from "https://en.wikipedia.org/w/index.php?title=Diphosphorus_tetraiodide&oldid=1158036868"