Rubidium iodide

Crystal structure
__ Rb +      __ I -
Crystal system	cubic
Space group	Fm 3 m (No. 225)
Lattice parameters	a 0 = 7.342 Å
General
Surname	Rubidium iodide
other names	Rubidium iodatum
Ratio formula	RbI
Brief description	white solid
External identifiers / databases
CAS number 7790-29-6 EC number 232-198-1 ECHA InfoCard 100.029.271 PubChem 3423208 Wikidata Q426446
properties
Molar mass	212.37 g mol −1
Physical state	firmly
density	3.11 g cm −3
Melting point	642-647 ° C
boiling point	1300 ° C
solubility	soluble in water (1520 g l −1 at 17 ° C)
Refractive index	1.647
safety instructions
GHS labeling of hazardous substances no GHS pictograms H and P phrases H: no H-phrases P: no P-phrases
Toxicological data	4708 mg kg −1 ( LD 50 ,  rat ,  oral )
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

Rubidium iodide is the rubidium salt of the hydroiodic acid HI.

presentation

Rubidium iodide can be produced from rubidium hydroxide by the salt formation reaction with hydriodic acid :

${\displaystyle \mathrm {\ RbOH+HI\ \rightarrow \ \ RbI+H_{2}O} }$

Also the synthesis of the elements is possible - metallic rubidium burns with elemental iodine in a violent reaction to rubidium iodide.

${\displaystyle \mathrm {2\ Rb(s)+I_{2}\ \rightarrow \ 2\ RbI} }$

properties

Rubidium iodide forms colorless crystals and is easily soluble in water. It has a red-violet flame color . The refractive index of the crystals is n _D  = 1.6474.

Rubidium iodide is only sparingly soluble in various organic solvents:

Solubility of RbI in organic solvents (given in g RbI in 100 cm 3 saturated solution)
solvent	0 ° C	25 ° C
Acetonitrile	1.478	1,350
Propionitrile	0.274	0.305
Nitromethane	0.567	0.518
acetone	0.960	0.674
Furfural		4.930

The standard enthalpy of formation of rubidium iodide is Δ _f H ⁰ ₂₉₈  = −328.7 kJ mol ⁻¹ , the standard free enthalpy of formation ΔG ⁰ ₂₉₈  = −325.7 kJ mol ⁻¹ , and the standard molar entropy S ⁰ ₂₉₈  = 118.11 J. K ⁻¹ mol ⁻¹ .

use

Rubidium iodide, along with other rubidium halides such as rubidium chloride and rubidium bromide, is used in medicine as a pain reliever , sedative and as an antidepressant . It is particularly used as a component of eye drops in which it is on the market under the names Rubjovit ^® (contains 8 mg / ml RbI) and Polijodurato ^® . However, there are studies that show that rubidium iodide has side effects that trigger allergies and cause inflammation . Homeopathic products containing rubidium iodide are available under the name 'Rubidium iodatum'.

Individual evidence

1. ↑ ^{a b c} Korth crystals: rubidium iodide
2. ↑ ^{a b c d e} data sheet Rubidium iodide, 99.8% (metals basis) from AlfaAesar, accessed on December 7, 2019 ( PDF )(JavaScript required) .
3. ↑ Web elements: Rubidium iodide
4. ↑ 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. 10-248.
5. ^ Jean D'Ans, Ellen Lax: Pocket book for chemists and physicists. 3. Elements, inorganic compounds and materials, minerals, Volume 3. 4. Edition, Springer, 1997, ISBN 978-3-5406-0035-0 , p. 688 ( limited preview in the Google book search).
6. ↑ Aterton Seidell: Solubilities Of Organic Compounds Vol - I , p. 1438. Full text
7. ↑ ^{a b c} R. E. Dickerson, HB Gray, H.-W. Sighting, MY Darensbourg: Principles of Chemistry , Verlag Walter de Gruyter 1988, ISBN 9783110099690 , p. 976. ( limited preview in Google book search)
8. ↑ Rubidium as an allergy reliever
9. ↑ N. Cameli, F. Bardazzi, R. Morelli, A. Tosti: Contact dermatitis from rubidium iodide in eyedrops. In: Contact Dermatitis. 23, 1990, p. 377, doi : 10.1111 / j.1600-0536.1990.tb05182.x .