Manganese(II) chloride

Manganese(II) chloride ;
Names:	manganese chloride; manganese(II) chloride;
Formula:	MnCl2 (anhydrous); MnCl2 · H2O (monohydrate); MnCl2 · 2H2O (dihydrate); MnCl2 · 4H2O (tetrahydrate);
Molar mass:	125.844 g/mol (anhydrous); 143.859 g/mol (monohydrate); 161.874 g/mol (dihydrate); 197.904 g/mol (tetrahydrate);
Density:	2.01 g/cm3 (tetrahydrate); 2.27 g/cm3 (dihydrate); 2.52 g/cm3 (monohydrate); 2.98 g/cm3 (anhydrous);
Crystal system:	monoclinic (tetrahydrate); a=6.19 Å, b=9.52 Å, c=11.19 Åα=90°, γ=90°; monoclinic (dihydrate); α=90°, γ=90°; orthorhombic (monohydrate); α=90°, β=90°, γ=90°; orthorhombic (anhydrous); α=90°, β=90°, γ=90°;
Shapes:	https://en.crystalls.info/w/uploads/media/3/36/Oblique_rhombic_prism.json Oblique rhombic prism https://en.crystalls.info/w/uploads/media/b/bc/Rhombic_prism.json Rhombic prism https://en.crystalls.info/w/uploads/media/5/51/Rhombic_pedion.json Rhombic pedion ;
Color:	pink; pale pink;
Decomposition point:	58 °C331.15 K <br />136.4 °F <br />596.07 °R <br /> (tetrahydrate); 135 °C408.15 K <br />275 °F <br />734.67 °R <br /> (dihydrate); 228 °C501.15 K <br />442.4 °F <br />902.07 °R <br /> (monohydrate);
Stability:	erodes (tetrahydrate)

Description

Inorganic compound, salt of transitional metal manganese and inorganic hydrochloric acid. From water solutions crystallizes as tetrahydrate, dihydrate and monohydrate.

Precursors

Reaction between manganese dioxide (black paste inside alkaline batteries) with Hydrochloric acid

Chemical equation:

MnO₂ + 4HCl = MnCl₂ + Cl₂ + 2H₂O↑

For preparation of 100.00g of manganese(II) chloride

tetrahydratetetrahydrate
dihydrate
monohydrate
anhydrous

а 43.93g of dioxide and 73.69g of hydrochloric acid is required.

Influence of pH level

Addition of hydrochloric acid prevents hydrolysis.

Notes

Solubility is on anhydrous terms. If MnO2 is heat treated, there may be no reaction, like most metal oxides. Battery grade contains copious amounts of iron, so high grade is obtained by multiple recrystallisations, as FeClx is highly soluble. Also react any manganese base like carbonate, hydroxide inc. metal (powder) with HCl works; Simple displacement will work on copper chloride with Mn metal, but other chlorides are unlikely to work reasonably rapidly as other transition metals too close in reactivity (even if Mn is the more reactive of them).

Storage conditions

For crystal storing use hermetic vessel with wadding moistened with such solution near the crystal. You can use such alternatives as vessel with vaseline or vegetable oil, organic non-hygroscopic solvent (kerosene or liquid paraffin). Also you can use acrylate polymer or another kinds of solidifying plastic.

Solubility

TableGraph

Temperature	g/`100,00` g water
0°C273.15 K <br />32 °F <br />491.67 °R <br />	`63.4`
10°C283.15 K <br />50 °F <br />509.67 °R <br />	`68.1`
20°C293.15 K <br />68 °F <br />527.67 °R <br />	`73.9`
25°C298.15 K <br />77 °F <br />536.67 °R <br />	`75.1`
30°C303.15 K <br />86 °F <br />545.67 °R <br />	`80.8`
40°C313.15 K <br />104 °F <br />563.67 °R <br />	`88.5`
60°C333.15 K <br />140 °F <br />599.67 °R <br />	`109.3`
80°C353.15 K <br />176 °F <br />635.67 °R <br />	`112.8`
90°C363.15 K <br />194 °F <br />653.67 °R <br />	`114.1`
100°C373.15 K <br />212 °F <br />671.67 °R <br />	`116.3`

Gallery

Manganese(II) chlorideRostislav DolgikhRostislav Dolgikh

Sources

R.A.Kiper Properties of compounds. Handbook

Chlorides
Salts	Ammonium chloride (NH₄Cl) • Barium chloride (BaCl₂) • Calcium chloride (CaCl₂) • Cadmium chloride (CdCl₂) • Cobalt(II) chloride (CoCl₂) • Copper(II) chloride (CuCl₂) • Iron(II) chloride (FeCl₂) • Iron(III) chloride (FeCl₃) • Lead(II) chloride (PbCl) • Manganese(II) chloride (MnCl₂) • Potassium chloride (KCl) • Sodium chloride (NaCl) • Strontium chloride (SrCl₂) • Tin(II) chloride (SnCl₂) • Zirconyl chloride (ZrOCl₂)
Double salts	Rubidium-gold(III)-palladium(II) chloride (2RbCl · AuCl₃ · PdCl₂)
Adducts	Diglycine hydrochloride (2NH₂CH₂COOH · HCl) • Glutamic acid hydrochloride (C₅H₉NO₄ · HCl) • Glucose and sodium chloride adduct (2C₆H₁₂O₆ · NaCl) • Hydroxylammonium chloride (NH₂OH · HCl) • P-nitroaniline hydrochloride (C₆H₆N₂O₂ · HCl) • Urea and sodium chloride adduct (CO(NH₄)₂ · NaCl)
Complexes	Ammonium pentachloroferrate(III) ((NH₄)₂[FeCl₅]) • Ammonium tetrachlorocuprate(II) ((NH₄)₂[CuCl₄]) • Lithium trioxalatoferrate(III)-chloride (Li₄[Fe(C₂O₄)₃]Cl) • Hexamminecobalt(III) chloride ([Co(NH₃)₆]Cl₂) • Hexaamminenickel chloride ([Ni(NH₃)₆]Cl₂) • Potassium hexachlororhodate(III) (K₃[RhCl₆])

Manganese compounds
Salts	Manganese(II) acetate (Mn(CH₃COO)₂) • Manganese(II) chloride (MnCl₂) • Manganese(II) formate (Mn(COOH)₂) • Manganese(II) sulfate (MnSO₄)
Double salts	Cerium(III)-cobalt-manganese nitrate (3(Co,Mn)(NO₃)₂ · 2Ce(NO₃)₃) • Cerium(III)-manganese nitrate (3Mn(NO₃)₂ · 2Ce(NO₃)₃) • Manganese(II)-ammonium sulfate ((NH₄)₂Mn(SO₄)₂) • Manganese(III)-ammonium sulfate (NH₄Mn(SO₄)₂) • Manganese(II)-potassium sulfate (K₂Mn(SO₄)₂)

Manganese(II) chloride
Names:	manganese chloride manganese(II) chloride
Formula:	MnCl₂ (anhydrous) MnCl₂ · H₂O (monohydrate) MnCl₂ · 2H₂O (dihydrate) MnCl₂ · 4H₂O (tetrahydrate)
Molar mass:	125.844 g/mol (anhydrous) 143.859 g/mol (monohydrate) 161.874 g/mol (dihydrate) 197.904 g/mol (tetrahydrate)
Density:	2.01 g/cm³ (tetrahydrate) 2.27 g/cm³ (dihydrate) 2.52 g/cm³ (monohydrate) 2.98 g/cm³ (anhydrous)
Crystal system:	monoclinic (tetrahydrate) a=6.19 Å, b=9.52 Å, c=11.19 Åα=90°, γ=90° monoclinic (dihydrate) α=90°, γ=90° orthorhombic (monohydrate) α=90°, β=90°, γ=90° orthorhombic (anhydrous) α=90°, β=90°, γ=90°
Shapes:	Oblique rhombic prism Rhombic prism Rhombic pedion
Color:	pink pale pink
Decomposition point:	58 °C331.15 K <br />136.4 °F <br />596.07 °R <br /> (tetrahydrate) 135 °C408.15 K <br />275 °F <br />734.67 °R <br /> (dihydrate) 228 °C501.15 K <br />442.4 °F <br />902.07 °R <br /> (monohydrate)
Stability:	erodes (tetrahydrate)