Strontium iodide

Crystal structure
__ Sr 2+      __ I -
Crystal system	orthorhombic
General
Surname	Strontium iodide
other names	Strontium (II) iodide Strontium diiodide
Ratio formula	SrI 2
Brief description	colorless, crystalline solid
External identifiers / databases
CAS number 10476-86-5 EC number 233-972-1 ECHA InfoCard 100.030.871 PubChem 25304 Wikidata Q417992
properties
Molar mass	341.43 g mol −1
Physical state	firmly
density	4.55 g cm −3
Melting point	507-645 ° C
boiling point	1773 ° C (decomposition)
solubility	in water: 4550 g l −1 (25 ° C) in ethanol : 31 g / l −1 (4 ° C)
safety instructions
GHS labeling of hazardous substances danger H and P phrases H: 314 P: 280-305 + 351 + 338-310
Toxicological data	800 mg kg −1 ( LD 50 ,  rat ,  ip )
As far as possible and customary, SI units are used. Unless otherwise noted, the data given apply to standard conditions .

Strontium iodide (also strontium (II) iodide) is the iodide of the alkaline earth metal strontium . The empirical formula is SrI ₂ .

presentation

Strontium iodide can be prepared by reacting strontium carbonate with hydrogen iodide .

${\displaystyle \mathrm {SrCO_{3}+2\ HI\longrightarrow SrI_{2}\ +H_{2}O+CO_{2}\uparrow } }$

properties

It is a white, crystalline, readily water-soluble solid that liquefies in a range of 507 to 645 ° C and decomposes at 1773 ° C. The compound is hygroscopic and turns yellowish in air. At high temperatures and in the presence of air, the compound breaks down completely to form strontium oxide and elemental iodine .

${\displaystyle \mathrm {2\ SrI_{2}+O_{2}\longrightarrow 2\ SrO+2\ I_{2}} }$

Various hydrates of strontium iodide exist. The hexahydrate SrI ₂  · 6 H ₂ O gives off four molecules of water of crystallization at 383  K in a nitrogen stream and changes into the dihydrate SrI ₂  · 2 H ₂ O.

Crystal structure and lattice constants of the hydrates of strontium iodide
designation	formula	Crystal system	Space group	a [pm]	b [pm]	c [pm]	β	Z
Anhydrate	SrI 2	orthorhombic	Pbca (No. 61)	1522	822	790	-	8th
Dihydrate	SrI 2  • 2 H 2 O	orthorhombic	Pcmn (No. 62, position 4)	1558.05	434.03	988.14	-	4th
Hexahydrate	SrI 2  • 6 H 2 O	trigonal	P 3 (No. 147)	851	-	429	-	2

use

Strontium iodide has been used for scintillator crystals for some time . The properties of such strontium iodide scintillators are desirable for medical purposes and also for safety-relevant applications in order to be able to identify and differentiate isotopes with them.

Web links

• Information at Webelements

Individual evidence

1. ↑ ^{a b c} data sheet strontium iodide from AlfaAesar, accessed on May 8, 2010 ( PDF )(JavaScript required) .
2. ^ Francis Turner: The Condensed Chemical Dictionary , New York, The Chemical Catalog Company, p. 449.
3. ↑ ^{a b c} Data sheet Strontium iodide from Sigma-Aldrich , accessed on April 23, 2011 ( PDF ).
4. ↑ Atherton Seidell: Solubilities Of Inorganic And Organic Substances: A Handbook Of The Most Reliable Quantitative Solubility Determinations , Kessinger Publishing, 2008, ISBN 1-4372-6497-2 .
5. ↑ Entry on strontium iodide in the ChemIDplus database of the United States National Library of Medicine (NLM)
6. ↑ Georg Brauer (Ed.), With the collaboration of Marianne Baudler a . a .: Handbook of Preparative Inorganic Chemistry. 3rd, revised edition. Volume II, Ferdinand Enke, Stuttgart 1978, ISBN 3-432-87813-3 , p. 923.
7. ↑ E. Bartley: Text-book of Medical and Pharmaceutical Chemistry , 5th Edition, Philadelphia, pp. 267-268.
8. ^ ^{A b} W. Buchmeier, HD Lutz: Structure of strontium iodide dihydrate in Acta Cryst. 1986 , C42 , pp. 651-653 doi: 10.1107 / S0108270186095045
9. ↑ E. Th. Rietschel, H. Bärnighausen: The crystal structure of strontium iodide SrI ₂ . In: Journal for inorganic and general chemistry , 368, 1969, pp. 62-72, doi: 10.1002 / zaac.19693680110 .
10. ↑ A metastable phase with the space group Pnma (No. 62) is also known (G. Liu, HA Eick: The Structure of a Metastable Form of SrI ₂ By the X-Ray Rietveld Procedure. In: Journal of the Less-Common Metals , 156, 1989, pp. 237-245, doi: 10.1016 / 0022-5088 (89) 90422-0 ).
11. ↑ Z. Herrmann: About the structures of strontium iodide, calcium chloride and calcium bromide hexahydrates in Zeitschrift für inorganic und Allgemeine Chemie 1931 , 197 (1), pp. 212-218. doi: 10.1002 / zaac.19311970118
12. ↑ LLNL Industrial Partnerships Office (IPO): Strontium Iodide Scintillator Detector ( Memento of February 16, 2013 in the Internet Archive ).