Manganese(II) iodide explained

Manganese(II) iodide is the chemical compound composed of manganese and iodide with the formula MnI₂(H2O)_n. The tetrahydrate is a pink solid while the anhydrous derivative is beige. Both forms feature octahedral Mn centers. Unlike MnCl₂(H₂O)₄ and MnBr₂(H₂O)₄ which are cis, MnI₂(H₂O)₄ is trans.

Preparation

Anhydrous MnI₂ is prepared from the elements:^[1]

The tetrahydrate can be prepared by treating manganese(II) carbonate with hydriodic acid. The anhydrous form can be produced from it by dehydration in a vacuum.^[2]

Properties

Samples turn brown in air under the influence of light as a result of the oxidation of the iodide ion to iodine.^[3] It has a trigonal crystal structure of the cadmium iodide type (polytype 2H)^{[4] [5]} with the space group Pm1 (space group no. 164). It dissolves in water and decomposes. The tetrahydrate has a monoclinic crystal structure with the space group P2₁/c (No. 14).^[6]

Applications

It is often used in the lighting industry.^[7]

Notes and References

1. 10.1055/s-1984-30724 . Organomanganous Reagents; IX. Preparation of Various Halogenated, Alkoxylated, Aryloxylated, and Arylsulfenylated Ketones from Correspondingly Functionalized Carboxylic Acid Chlorides or Anhydrides . 1984 . Friour . G. . Cahiez . G. . Normant . J. F. . Synthesis . 1984 . 37–40 . 94812612 .
2. 10.1016/S0020-1693(00)90464-X . The Coordination Chemistry of Manganese . 1981 . Hosseiny . Afshin . MacKie . Anthony G. . McAuliffe . Charles A. . Minten . Karl . Inorganica Chimica Acta . 49 . 99–105 .
3. Book: Ans, Jan d' . Elemente, anorganische Verbindungen und Materialien . Ans . Jan d' . 1998 . Verlag nicht ermittelbar . 978-3-540-60035-0 . 4., neubearb. u. rev. Aufl . Taschenbuch für Chemiker und Physiker / D'Ans . Ort nicht ermittelbar.
4. Book: Moderne anorganische Chemie: mit CD-ROM . 2007 . de Gruyter . 978-3-11-019060-1 . Riedel . Erwin . 3. Aufl . Berlin . Alsfasser . Ralf.
5. Neutron Diffraction Investigation of the Magnetic Order in MnI₂ . J. W. . Cable . M. K. . Wilkinson . E. O. . Wollan . W. C. . Koehler . . 125 . 6 . 1860-1864 . 1962 . 10.1103/PhysRev.125.1860 .
6. Moore . J. E. . Abola . J. E. . Butera . R. A. . 1985-09-15 . Structure of manganese(II) iodide tetrahydrate, MnI2.4H2O . Acta Crystallographica Section C: Crystal Structure Communications . en . 41 . 9 . 1284–1286 . 10.1107/S0108270185007466 . 0108-2701.
7. Book: Cepanec , Ivica . 2004 . Synthesis of Biaryls . Elseveir . 0-08-044412-1 . 104 . 2008-06-18 .