Lithium iodide, represented by the chemical formula LiI, is an inorganic compound with constituent elements lithium and iodine ^[1]. It can be easily identified because exposure to air changes its color from white to yellow due to the formation of iodine by oxidation of iodide ^[2]. LiI can exist in different hydrate forms, including monohydrate, dehydrate, and trihydrate ^[3].

Lithium Iodide Identification
CAS Number	Lithium iodide: 10377-51-2 [1] (6L)lithium iodide: 21752-61-4 [1] (7L)lithium iodide: 29911-74-8 [1]
PubChem CID	66321 [1]
ChemSpider ID	59699 [4]
EC Number	Lithium iodide: 233-822-5 [1] (6L)lithium iodide: 244-572-1 [1] (7L)lithium iodide: 249-952-0 [1]
UNII	S6K2XET783 [1]
InChI Key	HSZCZNFXUDYRKD-UHFFFAOYSA-M [1]

How is Lithium Iodide Prepared

Lithium iodide can be synthesized by combining lithium sulfide and strontium iodide, which can be represented by the double decomposition reaction given below ^[5]:

Li₂S + SrI₂ → SrS + 2LiI

Another method for anhydrous lithium iodide preparation involves the following reaction of lithium aluminum hydride with iodine in a diethyl-ether medium ^[6]:

LiAlH₄ + 2I₂ → 2H₂ + AlI₃ + LiI

When LiI is dissolved in water, the ions are stabilized by water molecules, giving off energy that is greater than the lattice energy of LiI. The dissolution of lithium iodide is thus exothermic.

Properties and Characteristics of Lithium Iodide

General Properties
Molar Mass/Molecular Weight	133.844 g/mol [1]
Physical Properties
Color and Appearance	White crystalline solid [7]
Melting Point	446-469 °C, 834.8-876.2 °F [4, 7]
Boiling Point	1170-1190 °C, 2138-2174 °F [4]
Density	4.08 g cm-3 [7]
State of matter at room temperature (solid/liquid/gas)	Solid [7]
Solubility	Soluble in water, methanol, acetone, and alcohol; very soluble in an aqueous solution of ammonia [4]
Solubility in Water	1510 g/L (at 0 °C), 1670 g/L (at 25 °C), 4330 g/L (at 100 °C)
Heat Capacity (C)	54.4 J/mol K or 0.381 J/g K
Magnetic Susceptibility (χ)	-50 X 10-6 cm3/mol
Chemical Properties
pH	N/A
Acid or base	N/A
Atomic Properties
Crystal Structure	Face-centered cubic lattice

Uses

• Iodide-based electrolytes containing lithium are potentially used in high-temperature batteries and long-life batteries, including artificial pacemakers ^{[8, 9]}.
• Lithium iodide crystals are grown for use as scintillation detectors of neutrons ^[10].
• It can be used for cleaving carbon-oxygen bonds, such as the conversion of methyl esters into carboxylic acid.

Is it Safe

Overexposure or repeated exposure can cause skin irritation ^[1]. Contact with eyes can cause serious eye damage ^[1].

References
1. Lithium Iodide – Pubchem.ncbi.nlm.nih.gov
2. Lithium iodide – Chem.libretexts.org
3. Higher hydrates of lithium chloride, lithium bromide and lithium iodide – Scripts.iucr.org
4. Lithium iodide – Chemspider.com
5. Chemical Equation Balancer – Chemicalaid.com
6. Preparation of anhydrous lithium iodide – Inis.iaea.org
7. Lithium Iodide – Americanelements.com
8. All-Lithium, Iodide-Based, Low-Melting Electrolytes for High-Temperature Batteries – Ecst.ecsdl.org
9. Trends in Cardiac Pacemakers – Ncbi.nlm.ih.gov
10. Some lithium iodide phosphors for slow neutron detection – Iopscience.iop.org