Manganese(II) acetate

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Crystal compoundsSaltsAcetatesManganese(II) acetate


  Manganese(II) acetate   
Names: manganese(II) acetate
manganese diacetate
manganouse acetate

Formula: Mn(CH3COO)2 (anhydrous)
Mn(CH3COO)2 · 4H2O (tetrahydrate)
SMILES: CC([O-])=O.CC([O-])=O.[Mn+2]
Molar mass: 173.026 g/mol (anhydrous)
245.085 g/mol (tetrahydrate)
Density: 1.74 g/cm3 (anhydrous)
1.589 g/cm3 (tetrahydrate)
Crystal system: monoclinic (tetrahydrate)
a=11.1 Å
11.1000 Å
1.1100 nm
, b=17.51 Å
17.5100 Å
1.7510 nm
, c=9.09 Å
9.0900 Å
0.9090 nm
α=90°
90°  
, β=118.62°
118°37′12.0″  
, γ=90°
90°  

Forms:
https://media.crystalls.info/w/uploads/media/Rhombic_pedion.json
https://media.crystalls.info/w/uploads/media/Parallelogram.json
https://media.crystalls.info/w/uploads/media/Rhombic_prism.json

Color: light-pink
Melting point: 80 °C
353.15 K
176 °F
635.67 °R
(tetrahydrate)
Decomposition point: 210 °C
483.15 K
410 °F
869.67 °R
(anhydrous)
Magnetic properties: paramagnetic
Stability: stable (tetrahydrate)
Hardness: very fragile
Toxicity: slightly toxic

Description

Organic compound, salt of bivalent transitional metal manganese and organic acetic acid. From water solutions crystallizes as tetrahydrate.

Precursors

Reaction between manganese(II) hydroxycarbonate, carbonate or hydroxide and excess of acetic acid

Chemical equation:

4CH3COOH + Mn2(CO3)(OH)2 = 2Mn(CH3COO)2 + 3H2O + CO2
2CH3COOH + MnCO3 = Mn(CH3COO)2 + H2O + CO2
2CH3COOH + Mn(OH)2 = Mn(CH3COO)2 + 2H2O

For preparation of 100.00g of manganese(II) acetate tetrahydrate а 41.60g of manganese hydroxycarbonate or 46.90g of carbonate or 36.29g of hydroxide and 70.01g of 70% acetic acid is required.
Add acid to the flask, then add small parts of manganese compound with stirring until it will totally dissolve or, if you use carbonate, until carbon dioxide emission will stop. After reaction will stop, filter the solution and use it for crystal growing.

Reaction between chloride, sulfate or manganese(II) nitrate and excess of concentrated acetic acid

Chemical equation:

2CH3COOH + MnCl2 = Mn(CH3COO)2↓ + 2HCl
2CH3COOH + MnSO4 = Mn(CH3COO)2↓ + H2SO4
2CH3COOH + Mn(NO3)2 = Mn(CH3COO)2↓ + 2HNO3

For preparation of 100.00g of manganese(II) acetate tetrahydrate а 80.75g of manganese(II) chloride tetrahydrate or 113.06g of manganese(II) sulfate heptahydrate or 117.12g of manganese(II) nitrate hexahydrate and 49.00g of glacial acid acetic or 70.01g of 70% acetic acid is required.
Add to the flask with hot manganese compounds solution a acid solution with heating and stirring. Cooling this mixture will cause forming a large amount of crystalline precipitation. Filter precipitate and wash it wish small amount of glacial acetic acid, then filter the solution and use it for crystal growing.

Reaction between manganese(II) nitrate and sodium acetate

Chemical equation:

2NaCH3COO + Mn(NO3)2 = Mn(CH3COO)2↓ + 2NaNO3

For preparation of 100.00g of manganese(II) acetate tetrahydrate а 117.12g of manganese(II) nitrate hexahydrate and 111.05g of sodium acetate trihydrate is required.
Add to the flask with hot manganese(II) nitrate solution a sodium acetate solution with heating and stirring. Cooling this mixture will cause forming a large amount of crystalline precipitation. Filter precipitate and wash it wish small amount of cold water, then filter the solution and use it for crystal growing.

Reaction between manganese(II) sulfate and calcium or lead(II) acetate

You can use manganese(II) chloride instead of sulfate if you use lead salt..
Chemical equation:

Ca(CH3COO)2 + MnSO4 = Mn(CH3COO)2 + CaSO4
Pb(CH3COO)2 + MnSO4 = Mn(CH3COO)2 + PbSO4
Pb(CH3COO)2 + MnCl2 = Mn(CH3COO)2 + PbCl2

For preparation of 100.00g of manganese(II) acetate tetrahydrate а 80.75g of manganese(II) chloride tetrahydrate or 113.06g of manganese(II) sulfate heptahydrate and 71.89g of calcium acetate monohydrate or 154.78g of lead(II) acetate trihydrate is required.
Add to the flask with calcium or lead acetate solution small parts of manganese salt solution and stir. The large amount of poorly soluble precipitate will form. Settle it out and discard, then filter the solution carefully.

Influence of impurities

Water solutions are hydrolytically unstable and rapidly oxidizes by atmospheric oxygen to brown manganese(III) acetate.
So it`s recommended to add excess of acetic acid for stopping the hydrolysis.

Notes

Usually forms a supersaturated solution. Crystallization begins after placing the crystal seed into solution.

Storage conditions

Store in its original form or under several layers of varnish at average humidity and room temperature. Do not store in matchboxes or cotton wool and do not heat.

Solubility

Temperatureгр/100,00 гр waterгр/100,00 гр methanol
(anhydrous)(tetrahydrate)(anhydrous)
0°C
273.15 K
32 °F
491.67 °R
~33
33 g/100g
24.812 %
15°C
288.15 K
59 °F
518.67 °R
4.76
4.76 g/100g
4.544 %
50°C
323.15 K
122 °F
581.67 °R
38.1
38.1 g/100g
27.589 %
64.5
64.5 g/100g
39.21 %
70°C
343.15 K
158 °F
617.67 °R
12.3
12.3 g/100g
10.953 %
Soluble in ethanol and acetic acid. Insoluble in acetone.

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