Manganese(II) iodide


Manganese iodide is the chemical compound composed of manganese and iodide with the formula MnI2n. The tetrahydrate is a pink solid while the anhydrous derivative is beige. Both forms feature octahedral Mn centers. Unlike MnCl24 and MnBr24 which are cis, MnI24 is trans.

Preparation

Anhydrous MnI2 is prepared from the elements:
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.

Properties

Samples turn brown in air under the influence of light as a result of the oxidation of the iodide ion to iodine. It has a trigonal crystal structure of the cadmium iodide type with the space group Pm1. It dissolves in water and decomposes. The tetrahydrate has a monoclinic crystal structure with the space group P21/c.

Applications

It is often used in the lighting industry.