Lithium iodide

Cubic

Li, I

Lithium iodide

Beige, odorless solid

Fixed

3.49 g · cm -3

446 ° C

1180 ° C

• Very well in water (1650 g · l-1 at 20 ° C)
• Very well in ethanol

1,955

Risk

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Lithium iodide, LiI, is the lithium salt of hydriodic acid. In addition to the anhydrous lithium iodide are also various hydrates, are known LiI · nH2O with n = 0.5, 1, 2 and 3

Production and representation

The preparation of lithium iodide are prepared by reacting aqueous lithium hydroxide or Lithiumcarbonatlösungen with hydrogen iodide and subsequent concentration and drying.

The anhydrous lithium iodide can be prepared in anhydrous diethyl ether by reaction of lithium hydride with iodine.

Properties

Lithium iodide forms colorless, highly hygroscopic crystals with a melting point of 446 ° C, a boiling point of 1180 ° C and a density of 3.49 g · cm -3. The molar mass of anhydrous lithium iodide is 133.85 g / mol. The oxidation of iodide to iodine by atmospheric oxygen, the crystals quickly yellowish to brownish color.

The trihydrate has a melting point of 72 ° C. When heated it loses one molecule of water of crystallization at 80 ° C, two molecules of water of crystallization at 300 ° C. Lithium iodide is soluble in water (1650 g / l water at 20 ° C ) and ethanol soluble.

The standard enthalpy of formation of crystalline lithium iodide is ΔfH0298 = -270.08 kJ / mol.

Use

The anhydrous lithium iodide is used in organic synthesis, in batteries, it serves as the electrolyte. Doped crystals serve as a scintillation detector for slow neutrons.