Manganese(II) iodide

Chemical compound From Wikipedia, the free encyclopedia

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.[2] Both forms feature octahedral Mn centers. Unlike MnCl2(H2O)4 and MnBr2(H2O)4 which are cis, MnI2(H2O)4 is trans.[3]

Quick facts Names, Identifiers ...
Manganese(II) iodide
Ball-and-stick model of part of a layer in the crystal structure of manganese(II) iodide
Ball-and-stick model of part of a layer in the crystal structure of manganese(II) iodide
Ball-and-stick model of layer stacking in the crystal structure of manganese(II) iodide
Ball-and-stick model of layer stacking in the crystal structure of manganese(II) iodide
Molecular structure of manganese(II) iodide tetrahydrate
Molecular structure of manganese(II) iodide tetrahydrate
Names
IUPAC name
Manganese(II) iodide
Identifiers
3D model (JSmol)
ChemSpider
ECHA InfoCard 100.029.274 Edit this at Wikidata
EC Number
  • 232-201-6
UNII
  • InChI=1S/2HI.Mn/h2*1H;/q;;+2/p-2 ☒N
    Key: QWYFOIJABGVEFP-UHFFFAOYSA-L ☒N
  • InChI=1/2HI.Mn/h2*1H;/q;;+2/p-2
    Key: QWYFOIJABGVEFP-NUQVWONBAL
  • [Mn+2].[I-].[I-]
Properties
MnI2
Molar mass 308.747 g/mol
Appearance pink crystalline
Density 5.01 g/cm3
Melting point 701 °C (1,294 °F; 974 K) (anhydrous)
80 °C (tetrahydrate)
Boiling point 1,033 °C (1,891 °F; 1,306 K)
soluble
+14,400·10−6 cm3/mol
Structure
Rhombohedral, hP3, SpaceGroup = P-3m1, No. 164
octahedral
Hazards[1]
GHS labelling:
GHS08: Health hazard
Danger
H360
P201, P202, P281, P308+P313, P405, P501
NFPA 704 (fire diamond)
NFPA 704 four-colored diamondHealth 1: Exposure would cause irritation but only minor residual injury. E.g. turpentineFlammability 0: Will not burn. E.g. waterInstability 1: Normally stable, but can become unstable at elevated temperatures and pressures. E.g. calciumSpecial hazards (white): no code
1
0
1
Flash point non-flammable
Related compounds
Other anions
 Manganese(II) fluoride
Manganese(II) chloride
Manganese(II) bromide
Other cations
 Iron(II) iodide
Cobalt(II) 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

Anhydrous MnI2 is prepared from the elements:[4]

Mn + I2 → MnI2

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.[5] It has a trigonal crystal structure of the cadmium iodide type (polytype 2H)[6][7] with the space group P3m1 (space group no. 164). It dissolves in water and decomposes.[5] The tetrahydrate has a monoclinic crystal structure with the space group P21/c (No. 14).[3]

Applications

It is often used in the lighting industry.[8]

References

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