Zinc iodide is the inorganic compound with the formula ZnI2. It exists both in anhydrous form and as a dihydrate. Both are white and readily absorb water from the atmosphere. It has no major application.

Zinc iodide
Names
IUPAC name
Zinc iodide
Other names
Zinc(II) iodide
Identifiers
3D model (JSmol)
ChemSpider
ECHA InfoCard 100.030.347 Edit this at Wikidata
UNII
  • InChI=1S/2HI.Zn/h2*1H;/q;;+2/p-2 checkY
    Key: UAYWVJHJZHQCIE-UHFFFAOYSA-L checkY
  • InChI=1/2HI.Zn/h2*1H;/q;;+2/p-2
    Key: UAYWVJHJZHQCIE-NUQVWONBAB
  • I[Zn]I
Properties
ZnI2
Molar mass 319.19 g/mol
Appearance white solid
Density 4.74 g/cm3
Melting point 446 °C (835 °F; 719 K)
Boiling point 1,150 °C (2,100 °F; 1,420 K) decomposes
450 g/100mL (20 °C)
−98.0·10−6 cm3/mol
Structure
Tetragonal, tI96
I41/acd, No. 142
Hazards
Flash point 625 °C (1,157 °F; 898 K)
Safety data sheet (SDS) External MSDS
Related compounds
Other anions
Zinc fluoride
Zinc chloride
Zinc bromide
Other cations
Cadmium iodide
Mercury(I) iodide
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
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Preparation

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It can be prepared by the direct reaction of zinc and iodine in water[1] or in refluxing ether.[2] or by treating zinc with iodine in aqueous solution:[3]

Zn + I2 → ZnI2

Structure as solid, gas, and in solution

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The structure of solid ZnI2 is unusual relative to the dichloride. While zinc centers are tetrahedrally coordinated, as in ZnCl2, groups of four of these tetrahedra share three vertices to form “super-tetrahedra” of composition {Zn4I10}, which are linked by their vertices to form a three-dimensional structure.[4] These "super-tetrahedra" are similar to the P4O10 structure.[4][5]

Molecular ZnI2 is linear as predicted by VSEPR theory with a Zn-I bond length of 238 pm.[4]

In aqueous solution the following have been detected: Zn(H2O)62+, [ZnI(H2O)5]+, tetrahedral ZnI2(H2O)2, ZnI3(H2O), and ZnI42−.[6]

Applications

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References

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  1. ^ F. Wagenknecht; R. Juza (1963). "Zinc iodide". In G. Brauer (ed.). Handbook of Preparative Inorganic Chemistry, 2nd Ed. Vol. 1. NY, NY: Academic Press. p. 1073.
  2. ^ Eagleson, M. (1994). Concise Encyclopedia Chemistry. Walter de Gruyter. ISBN 3-11-011451-8.
  3. ^ DeMeo, S. (1995). "Synthesis and Decomposition of Zinc Iodide: Model Reactions for Investigating Chemical Change in the Introductory Laboratory". Journal of Chemical Education. 72 (9): 836. Bibcode:1995JChEd..72..836D. doi:10.1021/ed072p836.
  4. ^ a b c Wells, A. F. (1984). Structural Inorganic Chemistry (5th ed.). Oxford Science Publications. ISBN 0-19-855370-6.
  5. ^ Fourcroy, P. H.; Carré, D.; Rivet, J. (1978). "Structure Cristalline de l'Iodure de Zinc ZnI2". Acta Crystallographica Section B: Structural Crystallography and Crystal Chemistry. 34 (11): 3160–3162. Bibcode:1978AcCrB..34.3160F. doi:10.1107/S0567740878010390.
  6. ^ Wakita, H.; Johansson, G.; Sandström, M.; Goggin, P. L.; Ohtaki, H. (1991). "Structure determination of zinc iodide complexes formed in aqueous solution". Journal of Solution Chemistry. 20 (7): 643–668. doi:10.1007/BF00650714. S2CID 97496242.
  7. ^ Baker, A.; Dutton, S.; Kelly, D., eds. (2004). Composite Materials for Aircraft Structures (2nd ed.). AIAA (American Institute of Aeronautics & Astronautics). ISBN 1-56347-540-5.
  8. ^ Ezrin, M. (1996). Plastics Failure Guide. Hanser Gardner Publications. ISBN 1-56990-184-8.
  9. ^ US patent 4109065, Will, F. G.; Secor, F. W., "Rechargeable aqueous zinc-halogen cell", issued 1978-08-22, assigned to General Electric 
  10. ^ Hayat, M. A. (2000). Principles and Techniques of Electron Microscopy: Biological Applications (4th ed.). Cambridge University Press. ISBN 0-521-63287-0.
  11. ^ Bercaw, John E.; Diaconescu, Paula L.; Grubbs, Robert H.; Kay, Richard D.; Kitching, Sarah; Labinger, Jay A.; Li, Xingwei; Mehrkhodavandi, Parisa; Morris, George E. (2006-11-01). "On the Mechanism of the Conversion of Methanol to 2,2,3-Trimethylbutane (Triptane) over Zinc Iodide". The Journal of Organic Chemistry. 71 (23): 8907–8917. doi:10.1021/jo0617823. ISSN 0022-3263. PMID 17081022.