Strontium iodide
# Strontium iodide

Strontium iodide $(SrI_2)$ is a salt of strontium and iodine. It is an ionic, water-soluble, and deliquescent compound that can be used in medicine as a substitute for potassium iodide . It is also used as a scintillation gamma radiation detector, typically doped with europium, due to its optical clarity, relatively high density, high effective atomic number (Z=48), and high scintillation light yield. In recent years, europium-doped strontium iodide $(SrI_2:Eu^{2+})$ has emerged as a promising scintillation material for gamma-ray spectroscopy with extremely high light yield and proportional response, exceeding that of the widely used high performance commercial scintillator $LaBr_3:Ce^{3+}.$ Large diameter $SrI_2$ crystals can be grown reliably using vertical Bridgman technique and are being commercialized by several companies.

## Reactions

Strontium iodide can be prepared by reacting strontium carbonate with hydroiodic acid:

    $SrCO_3$ + 2 HI → $SrI_2$ + $H_2O$ + $CO_2$

Strontium iodide forms a white powder that slowly changes to a yellowish colour when exposed to air. At high temperatures (in the presence of air) strontium iodide completely decomposes to form strontium oxide and free iodine.

