Manganese(II) chloride is the dichloride salt of manganese, MnCl2. This inorganic chemical exists in the anhydrous form, as well as the dihydrate (MnCl2·2H2O) and tetrahydrate (MnCl2·4H2O), with the tetrahydrate being the most common form. Like many Mn(II) species, these salts are pink, with the paleness of the color being characteristic of transition metal complexes with high spin d5 configurations. It is a paramagnetic salt.
hyperchloride of manganese
3D model (JSmol)
CompTox Dashboard (EPA)
|Molar mass||125.844 g/mol (anhydrous)|
161.874 g/mol (dihydrate)
197.91 g/mol (tetrahydrate)
|Appearance||pink solid (tetrahydrate)|
|Density||2.977 g/cm3 (anhydrous) |
2.27 g/cm3 (dihydrate)
2.01 g/cm3 (tetrahydrate)
|Melting point|| 654 °C (1,209 °F; 927 K) (anhydrous) |
dihydrate dehydrates at 135 °C
tetrahydrate dehydrates at 58 °C
|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||slightly soluble in pyridine, soluble in ethanol |
insoluble in ether
|NFPA 704 (fire diamond)|
|Lethal dose or concentration (LD, LC):|
LD50 (median dose)
|250-275 mg/kg (rat, oral)|
1715 mg/kg (mouse, oral)
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
(what is ?)
Manganese chloride is produced by treating manganese(IV) oxide with concentrated hydrochloric acid.
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.
Anhydrous MnCl2 adopts a layered cadmium chloride-like structure. The tetrahydrate consists of octahedral cis-Mn(H2O)4Cl2 molecules. The trans isomer, which is metastable, is also known. The dihydrate MnCl2(H2O)2 is a coordination polymer. Each Mn center is coordinated to four doubly bridging chloride ligands. The octahedron is completed by a pair of mutually trans aquo ligands.
Upon treatment with typical organic ligands, manganese(II) undergoes oxidation by air to give Mn(III) complexes. Examples include [Mn(EDTA)]−, [Mn(CN)6]3−, and [Mn(acetylacetonate)3]. Triphenylphosphine forms a labile 2:1 adduct:
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 tetrahydrofuran (THF).
Aqueous solutions of manganese(II) chloride are used in 31P-NMR to determine the size and lamellarity of phospholipid vesicles. When manganese chloride is added to a vesicular solution, Mn2+ paramagnetic ions are released, perturbing the relaxation time of the phospholipids' phosphate groups and broadening the resulting 31P resonance signal. Only phospholipids located in the outermost monolayer exposed to Mn2+ experience this broadening. The effect is negligible for multilamellar vesicles, but for large unilamellar vesicles, a ~50% reduction in signal intensity is observed.
Scacchite is the natural, anhydrous form of manganese(II) chloride. The only other currently known mineral systematized as manganese chloride is kempite - a representative of the atacamite group, a group of hydroxide-chlorides.
Manganism, or manganese poisoning, can be caused by long-term exposure to manganese dust or fumes.
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