Difference between revisions of "Manganese(II) chloride"

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(Created page with "{{Chembox | Name = Manganese(II) chloride | Reference = | IUPACName = Manganese(II) chloride | PIN = | SystematicName = | OtherNames = Manganese bichloride<br>Manganese dic...")
 
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The double replacement reaction between [[manganese(II) sulfate]] and [[calcium chloride]] will give manganese dichloride, while [[calcium sulfate]] precipitates out of the reaction. Manganese sulfate can be easily obtained by bubbling [[sulfur dioxide]] in an aqueous suspension of manganese dioxide.
 
The double replacement reaction between [[manganese(II) sulfate]] and [[calcium chloride]] will give manganese dichloride, while [[calcium sulfate]] precipitates out of the reaction. Manganese sulfate can be easily obtained by bubbling [[sulfur dioxide]] in an aqueous suspension of manganese dioxide.
  
:MnSO<sub>4</sub> + CaCl<sub>2</sub> → MnCl<sub>2</sub> + CaSO<sub>4</sub>
+
: MnSO<sub>4</sub> + CaCl<sub>2</sub> → MnCl<sub>2</sub> + CaSO<sub>4</sub>
  
Filter the resulting suspension remove the insoluble calcium sulfate and concentrate the MnCl<sub>2</sub> solution, then cool it to obtain the compound as pure crystals. Further recrystallization is required to remove iron.
+
Filter the resulting suspension remove the insoluble calcium sulfate and concentrate the MnCl<sub>2</sub> solution, then cool it to obtain the compound as pure crystals. If the manganese dioxide you use is from batteries, further recrystallization is required to remove iron impurities.
  
All the above procedures will give the hydrated form of this salt. To obtain the anhydrous form, you will need to heat the compound in the absence of air, like under inert gas or an organic solvent like methanol, or in a stream of hydrogen chloride.
+
All the above procedures will give the hydrated form of this salt. To obtain the anhydrous form, you will need to heat the compound in the absence of air, like under inert gas or an organic solvent like methanol, or in a stream of [[hydrogen chloride]].
  
 
A route to obtain the anhydrous form involves reacting manganese metal with dry hydrogen chloride gas, or chlorine at high temperatures.
 
A route to obtain the anhydrous form involves reacting manganese metal with dry hydrogen chloride gas, or chlorine at high temperatures.

Revision as of 21:15, 18 November 2017

Manganese(II) chloride
Names
IUPAC name
Manganese(II) chloride
Other names
Manganese bichloride
Manganese dichloride
Manganous chloride
Scacchite
Properties
MnCl2
Molar mass 125.844 g/mol (anhydrous)
161.874 g/mol (dihydrate)
197.91 g/mol (tetrahydrate)
Appearance Off-white solid (anhydrous)
Pink solid (hydrated)
Odor Odorless
Density 2.977 g/cm3 (anhydrous)
2.27 g/cm3 (dihydrate)
2.01 g/cm3 (tetrahydrate)
Melting point anhydrous
654 °C (1,209 °F; 927 K)
dihydrate
135 °C (275 °F; 408 K) (decomposes)
tetrahydrate
58 °C (136 °F; 331 K) (decomposes)
Boiling point 1,225 °C (2,237 °F; 1,498 K)
63.4 g/100 ml (0 °C)
73.9 g/100 ml (20 °C)
88.5 g/100 ml (40 °C)
123.8 g/100 ml (100 °C)
Solubility Soluble in ethanol, methanol
Slightly soluble in pyridine
Insoluble in ethers, halocarbons, hydrocarbons
Vapor pressure ~0 mmHg
Hazards
Safety data sheet Sigma-Aldrich (anhydrous)
Sigma-Aldrich (tetrahydrate)
Flash point Non-flammable
Lethal dose or concentration (LD, LC):
250-275 mg/kg (rat, oral)
1,715 mg/kg (mouse, oral)
Related compounds
Related compounds
Chromium(III) chloride
Iron(II) chloride
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
Infobox references

Manganese(II) chloride is the chemical compound with the formula MnCl2, a salt of manganese metal. It is available as anhydrous, monohydrate, dihydrate and tetrahydrate.

It occurs in nature as the rare mineral scacchite, first identified in the volcanic fumaroles of Vesuvius.

Properties

Chemical

Manganese(II) chloride is a weak Lewis acid.

Addition of organic ligands to solutions of manganese(II) and oxidation in air will give Mn(III) complexes.

Physical

Manganous chloride is a pink solid, soluble in water.

Availability

Manganese(II) chloride is sold by chemical suppliers.

Preparation

Manganese chloride is produced by treating manganese dioxide with concentrated hydrochloric acid.

MnO2 + 4 HCl → MnCl2 + 2 H2O + Cl2

Since the reaction releases chlorine gas, this must be done outside or in a fumehood.

Chlorine-free routes involve adding the hydrochloric acid to manganese metal or manganese carbonate/hydroxide.

Mn + 2 HCl → MnCl2 + H2
Mn(OH)2 + 2 HCl → MnCl2 + 2 H2O
MnCO3 + 2 HCl → MnCl2 + H2O + CO2

Manganese carbonate can be obtained by reacting manganese dioxide with oxalic acid.

The double replacement reaction between manganese(II) sulfate and calcium chloride will give manganese dichloride, while calcium sulfate precipitates out of the reaction. Manganese sulfate can be easily obtained by bubbling sulfur dioxide in an aqueous suspension of manganese dioxide.

MnSO4 + CaCl2 → MnCl2 + CaSO4

Filter the resulting suspension remove the insoluble calcium sulfate and concentrate the MnCl2 solution, then cool it to obtain the compound as pure crystals. If the manganese dioxide you use is from batteries, further recrystallization is required to remove iron impurities.

All the above procedures will give the hydrated form of this salt. To obtain the anhydrous form, you will need to heat the compound in the absence of air, like under inert gas or an organic solvent like methanol, or in a stream of hydrogen chloride.

A route to obtain the anhydrous form involves reacting manganese metal with dry hydrogen chloride gas, or chlorine at high temperatures.

Projects

  • Make dry cell batteries
  • Make Mn coordination complexes

Handling

Safety

Manganese dichloride is harmful in ingested. Long-term exposure to manganese dust or compounds will lead to manganese poisoning or manganism.

Storage

Manganese(II) chloride should be kept in closed containers.

Disposal

Manganese(II) chloride should be precipitated to manganese dioxide and then sent to waste disposal centers. Waste batteries centers might also pick up manganese waste.

Diluted manganese chloride can be used as source of manganese for plants.

References

Relevant Sciencemadness threads