Cesium iodide

Crystal structure
	__ Cs + __ I -
Crystal system	cubic
Space group	Pm 3 m (No. 221)
Lattice parameters	a = 4.5679 Å
Coordination numbers	Cs [8], I [8]
General
Surname	Cesium iodide
other names	Cesium iodide
Ratio formula	CsI
Brief description	colorless and odorless solid
External identifiers / databases
EC number	232-145-2
ECHA InfoCard	100.029.223
PubChem	24601
ChemSpider	23003
Wikidata	Q50703
properties
Molar mass	259.83 g mol −1
Physical state	firmly
density	4.51 g cm −3
Melting point	626 ° C
boiling point	1280 ° C
solubility	good in water (440 g l −1 at 20 ° C)
Refractive index	1.7873
safety instructions
H and P phrases	H: 361-400
	P: 201-281-308 + 313-260-273
Toxicological data	2386 mg kg −1 ( LD 50 , rat , oral )
Thermodynamic properties
ΔH f 0	−347 kJ mol −1
	As far as possible and customary, SI units are used. Unless otherwise noted, the data given apply to standard conditions . Refractive index: Na-D line , 20 ° C

Cesium iodide (also cesium iodide) is a white, crystalline salt with the empirical formula Cs I , which is used in IR , UV and X-ray spectroscopy . It is a salt of hydriodic acid . The material is very soft, difficult to polish and sensitive to humidity . The maximum application temperature is 200 ° C.

properties

Cesium iodide has a refractive index of 1.73916 and a reflection loss of 13.6% at a wavelength of 10.0 µm. It is translucent in the range 0.24–70 µm. The thermal conductivity is 1.13 W / (m · K) and the specific heat capacity is 201 J / (kg · K).

Cesium iodide is heat-stable up to approx. 600 ° C; thermal decomposition begins at 670–800 ° C.

The standard enthalpy of formation of cesium iodide is Δ H _f⁰ = −347 kJ / mol.

CsI (Tl) for scintillator

Cesium iodide can be used as a transparent scintillation material in scintillation counters. The high-energy radiation creates a so-called electromagnetic shower in the crystal , the photons of which are then converted into a measurable electrical signal with a photomultiplier . It can be used undoped or doped with thallium (Tl) or sodium (Na) as a scintillation material.

As an undoped material, it is also used as a beam splitter in IR spectroscopy .

↑ ^a ^b ^c ^d data sheet cesium iodide from AlfaAesar, accessed on February 16, 2010 ( PDF )(JavaScript required) .
↑ Entry on cesium compounds. In: Römpp Online . Georg Thieme Verlag, accessed on September 29, 2014.
^ CRC: Handbook of Chemistry and Physics . 55th edition. CRC-Press, 1974, ISBN 0-87819-454-1 .
↑ David R. Lide (Ed.): CRC Handbook of Chemistry and Physics . 90th edition. (Internet version: 2010), CRC Press / Taylor and Francis, Boca Raton, FL, Index of Refraction of Inorganic Crystals, pp. 10-246.
↑ ^a ^b Entry on cesium iodide in the GESTIS substance database of the IFA , accessed on January 10, 2017(JavaScript required) .
^ ^A ^b A. F. Holleman , E. Wiberg , N. Wiberg : Textbook of Inorganic Chemistry . 101st edition. Walter de Gruyter, Berlin 1995, ISBN 3-11-012641-9 , p. 1170.
^ IA Kulikov, ML Malyshev: Radiation-chemical decomposition of CsI . In: Atomic Energy 1983 , 55 (5), pp. 316-318. doi : 10.1007 / BF01123994
↑ E. Riedel: Inorganic Chemistry . 8th edition, de Gruyter, Berlin 2011, ISBN 9783110225679 . P. 624.