Chromium (II) chloride

Crystal structure
__ Cr 2+      __ Cl -
General
Surname	Chromium (II) chloride
Ratio formula	CrCl 2
Brief description	moisture-sensitive, air-sensitive, hygroscopic, gray odorless solid
External identifiers / databases
CAS number 10049-05-5 EC number 233-163-3 ECHA InfoCard 100.030.136 PubChem 24871 Wikidata Q416894
properties
Molar mass	122.90 g mol −1
Physical state	firmly
density	2.88 g cm −3
Melting point	823-825 ° C
solubility	soluble in water
safety instructions
GHS labeling of hazardous substances Caution H and P phrases H: 302-315-319-335 P: 280-301 + 330 + 331-302 + 352-304 + 340-332 + 313-337 + 313
Toxicological data	1870 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 .

Chromium (II) chloride is a chemical compound from the group of chromium compounds and chlorides .

Extraction and presentation

Chromium (II) chloride is obtained by reducing chromium (III) chloride with hydrogen at 500 ° C:

${\displaystyle \mathrm {2\ CrCl_{3}+H_{2}\longrightarrow 2\ CrCl_{2}+2\ HCl} }$

To a lesser extent, lithium aluminum hydride LiAlH ₄ or the like can also be used for the reduction

${\displaystyle \mathrm {4\ CrCl_{3}+LiAlH_{4}\longrightarrow 4\ CrCl_{2}+LiCl+AlCl_{3}+2\ H_{2}} }$

Reduction by zinc is also possible.

${\displaystyle \mathrm {2\ CrCl_{3}+Zn\longrightarrow 2\ CrCl_{2}+ZnCl_{2}} }$

properties

Chromium (II) chloride is a moisture-sensitive, air-sensitive, hygroscopic , gray, odorless solid. It has an orthorhombic crystal structure (distorted rutile type, space group Pnnm (space group no. 58) ) similar to that of calcium chloride with a = 664, b = 598 and c = 348  pm .

use

Chromium (II) chloride is used as a catalyst , reducing agent and absorbent for oxygen . It is also used in the Nozaki-Hiyama-Kishi reaction .

Individual evidence

1. ↑ ^{a b c d e f g h i} Entry on chromium (II) chloride in the GESTIS substance database of the IFA , accessed on January 8, 2018(JavaScript required) .
2. ^ Burg, AB: Anhydrous Chromium (II) Chloride . In: Inorganic Syntheses . 3, 1950, pp. 150-153. doi : 10.1002 / 9780470132340 .
3. ↑ JW Tracy, NW Gregory et al. a .: The crystal structure of chromium (II) chloride. In: Acta Crystallographica. 14, p. 927, doi : 10.1107 / S0365110X61002710 .