Manganese (II) chloride

Crystal structure
	__ Mn 2+ __ Cl -
General
Surname	Manganese (II) chloride
other names	Manganese dichloride
Ratio formula	MnCl 2 (anhydrous); MnCl 2 2 H 2 O (dihydrate); MnCl 2 4 H 2 O (tetrahydrate);
Brief description	white to light purple (anhydrous) or pale pink (tetrahydrate), odorless solid
External identifiers / databases
EC number	231-869-6
ECHA InfoCard	100,028,972
PubChem	24480
ChemSpider	22888
Wikidata	Q421071
properties
Molar mass	125.84 g · mol -1 (anhydrous); 161.87 g / mol −1 (dihydrate); 197.91 g mol −1 (tetrahydrate);
Physical state	firmly
density	2.98 g cm −3 (25 ° C, anhydrous); 2.27 g cm −3 (20 ° C, dihydrate); 2.01 g cm −3 (20 ° C, tetrahydrate);
Melting point	650 ° C (anhydrous); 58 ° C (tetrahydrate);
boiling point	1190 ° C
solubility	in water: * 723 g l −1 (anhydrous, 20 ° C) * 1200 g l −1 (dihydrate, 20 ° C) * 1980 g l −1 (tetrahydrate, 20 ° C)
safety instructions
H and P phrases	H: 302-318-373-411
	P: 260-264-270-280-305 + 351 + 338-310
MAK	0.5 mg m −3
	As far as possible and customary, SI units are used. Unless otherwise noted, the data given apply to standard conditions .

Manganese (II) chloride is a pale pink-red powder. The compound consists of manganese and chlorine and is usually present as a tetrahydrate or in anhydrous form.

Extraction and presentation

Manganese (II) chloride tetrahydrate can be produced by reacting manganese , manganese (II) carbonate or manganese dioxide with concentrated hydrochloric acid:

{\ displaystyle \ mathrm {1) \ Mn + 2 \ HCl \ longrightarrow \ MnCl_ {2} + H_ {2}}}

{\ displaystyle \ mathrm {2) \ MnCO_ {3} +2 \ HCl \ longrightarrow \ MnCl_ {2} + CO_ {2} + H_ {2} O}}

{\ displaystyle \ mathrm {3) \ MnO_ {2} +4 \ HCl \ longrightarrow \ MnCl_ {2} +2 \ H_ {2} O + Cl_ {2}}}

The anhydrous MnCl ₂ can be obtained from the tetrahydrate on heating in a stream of dry hydrogen chloride .

properties

Manganese (II) chloride tetrahydrate

Manganese (II) chloride forms pale pink hygroscopic crystals. It is very soluble in water and ethanol . In solution, the color is due to the hexaquamanganese (II) cation, [Mn (H ₂ O) ₆ ] ²⁺ . The tetrahydrate is in the form of an octahedral complex in which the two chloride ligands are in the cis position. With an excess of chloride ions, the complex anions MnCl ₄²⁻ (tetrachloromanganate (II), tetrahedral ) or MnCl ₆⁴⁻ (hexachloromanganate (II), octahedral) are formed.

use

Manganese (II) chloride is used to produce manganese brown Mn (O) OH and as a starting material for the synthesis of manganese-containing catalysts .

Individual evidence

↑ ^a ^b ^c ^d ^e ^f ^g ^h ⁱ ^j ^k ^l ^m Entry on manganese (II) chloride in the GESTIS substance database of the IFA , accessed on January 8, 2020(JavaScript required) .

[GESTIS-1] ↑ ^a ^b ^c ^d ^e ^f ^g ^h ⁱ ^j ^k ^l ^m Entry on manganese (II) chloride in the GESTIS substance database of the IFA , accessed on January 8, 2020(JavaScript required) .