Misplaced Pages

This is an old revision of this page, as edited by Beetstra (talk | contribs) at 10:59, 6 December 2010 (Script assisted update of identifiers from ChemSpider, CommonChemistry and FDA for the Chem/Drugbox validation project - Updated: InChI1->InChI StdInChI StdInChIKey.). The present address (URL) is a permanent link to this revision, which may differ significantly from the current revision.

Manganese(II) chloride

Names
IUPAC names Manganese(II) chloride Manganese dichloride
Other names Manganous chloride
Identifiers
CAS Number	7773-01-5 38639-72-4 (dihydrate) 13446-34-9 (tetrahydrate)
3D model (JSmol)	Interactive image
ChemSpider	22888
ECHA InfoCard	100.028.972
PubChem CID	24480
RTECS number	OO9625000
UNII	6YB4901Y90
CompTox Dashboard (EPA)	DTXSID9040681
InChI InChI=1S/2ClH.Mn/h2*1H;/q;;+2/p-2Key: GLFNIEUTAYBVOC-UHFFFAOYSA-L Key: GLFNIEUTAYBVOC-NUQVWONBAP
SMILES ClCl
Properties
Chemical formula	MnCl2
Molar mass	125.844 g/mol (anhydrous) 161.874 g/mol (dihydrate) 197.91 g/mol (tetrahydrate)
Appearance	pink solid (tetrahydrate)
Density	2.98 g/cm (anhydrous) 2.27 g/cm (dihydrate) 2.01 g/cm (tetrahydrate)
Melting point	654 °C (anhydrous) 135 °C (dihydrate) 58 °C (tetrahydrate)
Boiling point	1225 °C
Solubility in water	high
Structure
Crystal structure	CdCl2
Coordination geometry	octahedral
Hazards
NFPA 704 (fire diamond)	2 0 0
Flash point	Non-flammable
Related compounds
Other anions	Manganese(II) fluoride Manganese(II) bromide Manganese(II) iodide
Other cations	Manganese(III) chloride Technetium(IV) chloride Rhenium(III) chloride Rhenium(IV) chloride Rhenium(V) chloride Rhenium(VI) chloride
Except where otherwise noted, data are given for materials in their standard state (at 25 °C , 100 kPa). Y verify (what is  ?) Infobox references

Manganese(II) chloride describes a series of compounds with the formula MnCl₂(H₂O)_x, where the value of x can be 0, 2, or 4. The tetrahydrate is the most common form of "manganese(II) chloride". MnCl₂·4H₂O, but the anhydrous form and dihydrate MnCl₂·2H₂O are also known. Like many Mn(II) species, these salts are pink, the paleness of the color being characteristic of transition metal complexes with high spin d configurations.

Preparation

Manganese chloride is produced by treating manganese(IV) oxide with concentrated hydrochloric acid.

MnO₂ + 4 HCl → MnCl₂ + 2 H₂O + Cl₂

This reaction was once used for the manufacture of chlorine. By carefully neutralizing the resulting solution with MnCO₃, one can selectively precipitate iron salts, which are common impurities in manganese dioxide.

In the laboratory, manganese chloride can be prepared by treating manganese metal or manganese(II) carbonate and hydrochloric acid:

Mn + 2 HCl → MnCl₂ + H₂

MnCO₃ + 2 HCl → MnCl₂ + H₂O + CO₂

Chemical properties

Anhydrous MnCl₂ is a polymeric solid, which adopts a layered cadmium chloride-like structure. The tetrahydrate consists of octahedral trans-Mn(H₂O)₄Cl₂ molecules The hydrates dissolve in water to give mildly acidic solutions with a pH of around 4.

It is a weak Lewis acid, reacting with chloride ions to produce a series of solids containing the following ions , , and . Both and are polymeric.

Upon treatment with typical organic ligands, manganese(II) undergoes oxidation by air to give Mn(III) complexes. Examples include , , and . Triphenylphosphine forms a labile 2:1 adduct:

MnCl₂ + 2 Ph₃P →

Anhydrous manganese(II) chloride serves as a starting point for the synthesis of a variety of manganese compounds. For example, manganocene is prepared by reaction of MnCl₂ with a solution of sodium cyclopentadienide in THF.

MnCl₂ + 2 NaC₅H₅ → Mn(C₅H₅)₂ + 2 NaCl

Applications

The main application is used in the production of dry cell batteries. It is the precursor to the antiknock compound methylcyclopentadienyl manganese tricarbonyl.

Vesicle characterization with P-NMR

MnCl₂ is used in P-NMR to determine the size and lamellarity of phospholipid vesicles. When manganese chloride is added to a vesicular solution, Mn paramagnetic ions are released, perturbing the relaxation time of the phospholipids' phosphate groups and broadening the resulting P resonance signal. Only phospholipids located in the outermost monolayer exposed to Mn experience this broadening. The effect is negligle for multilamellar vesicles, but for large unilamellar vesicles, a ~50% reduction in signal intensity is observed.

Precautions

Manganism, or manganese poisoning, can be caused by long-term exposure to manganese dust or fumes.

References

1. N. N. Greenwood, A. Earnshaw, Chemistry of the Elements, 2nd ed., Butterworth-Heinemann, Oxford, UK, 1997.
2. ^ Reidies, Arno H. (2002), "Manganese Compounds", Ullmann's Encyclopedia of Industrial Chemistry, Weinheim: Wiley-VCH, doi:10.1002/14356007.a16_123, ISBN 3-527-30385-5.
3. ' A. F. Wells, Structural Inorganic Chemistry, 5th ed., Oxford University Press, Oxford, UK, 1984.
4. Frohlich, Margret; Brecht, Volker; Peschka-Suss, Regine (January 2001), "Parameters influencing the determination of liposome lamellarity by -NMR", Chemistry and Physics of Lipids, 109 (1): 103–112 {{citation}}: Unknown parameter |month= ignored (help)CS1 maint: date and year (link)
5. Hope; Bally; Webb; Cullis (1985), "Production of large unilamellar vesicles by a rapid extrusion procedure. Characterization of size distribution, trapped volume and ability to maintain a membrane potential" (PDF), Biochimica et Biophysica Acta, 812: 55–65 {{citation}}: Unknown parameter |date received= ignored (help)

External links

• National Pollutant Inventory: Manganese and compounds Fact Sheet

• Chlorides
• Manganese compounds
• Metal halides