Strontium iodide (SrI₂) is a

salt Salt is a mineral composed primarily of sodium chloride (NaCl), a chemical compound belonging to the larger class of salts; salt in the form of a natural crystalline mineral is known as rock salt or halite. Salt is present in vast quant ...

strontium Strontium is the chemical element with the symbol Sr and atomic number 38. An alkaline earth metal, strontium is a soft silver-white yellowish metallic element that is highly chemically reactive. The metal forms a dark oxide layer when it is e ...

and

iodine Iodine is a chemical element with the Symbol (chemistry), symbol I and atomic number 53. The heaviest of the stable halogens, it exists as a semi-lustrous, non-metallic solid at standard conditions that melts to form a deep violet liquid at , ...

. It is an ionic, water-soluble, and

deliquescent Hygroscopy is the phenomenon of attracting and holding water molecules via either absorption or adsorption from the surrounding environment, which is usually at normal or room temperature. If water molecules become suspended among the substance' ...

compound that can be used in medicine as a substitute for

potassium iodide Potassium iodide is a chemical compound, medication, and dietary supplement. It is a medication used for treating hyperthyroidism, in radiation emergencies, and for protecting the thyroid gland when certain types of radiopharmaceuticals are u ...

. It is also used as a scintillation

gamma radiation A gamma ray, also known as gamma radiation (symbol γ or \gamma), is a penetrating form of electromagnetic radiation arising from the radioactive decay of atomic nuclei. It consists of the shortest wavelength electromagnetic waves, typically s ...

detector, typically doped with

europium Europium is a chemical element with the symbol Eu and atomic number 63. Europium is the most reactive lanthanide by far, having to be stored under an inert fluid to protect it from atmospheric oxygen or moisture. Europium is also the softest lan ...

, 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 (SrI₂:Eu²⁺) 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 LaBr₃:Ce³⁺. Large diameter SrI₂ 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 Hydroiodic acid (or hydriodic acid) is an aqueous solution of hydrogen iodide (HI). It is a strong acid, one that is ionized completely in an aqueous solution. It is colorless. Concentrated solutions are usually 48% to 57% HI. Reactions Hy ...

: : SrCO₃ + 2 HI → SrI₂ + H₂O + CO₂ 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 Strontium oxide or strontia, SrO, is formed when strontium reacts with oxygen. Burning strontium in air results in a mixture of strontium oxide and strontium nitride. It also forms from the decomposition of strontium carbonate SrCO3. It is a stro ...

and free

References

{{Iodides Iodides Strontium compounds Alkaline earth metal halides