Manganese oxalate

Manganese oxalate is an inorganic compound with the chemical formula MnC₂O₄.^[3][4] Solid samples are pale pink and insoluble in water. At least two hydrates have been observed.^[5] It occurs naturally as the mineral Lindbergite.^[6]

Manganese oxalate

Portion of manganese(II) oxalate dihydrate crystal (red = O, blue = Mn, white = H)[1]
Names
Other names Manganese(II) oxalate, Manganese(2+) oxalate, Lindbergite
Identifiers
CAS Number	640-67-5 Y
3D model (JSmol)	Interactive image
ChemSpider	62705
ECHA InfoCard	100.010.335
EC Number	211-367-3
PubChem CID	69499
UNII	A8PK5I86G8 Y
CompTox Dashboard (EPA)	DTXSID90894218
InChI InChI=1S/C2H2O4.Mn/c3-1(4)2(5)6;/h(H,3,4)(H,5,6);/q;+2/p-2 Key: RGVLTEMOWXGQOS-UHFFFAOYSA-L
SMILES C(=O)(C(=O)[O-])[O-].[Mn+2]
Properties
Chemical formula	C2MnO4
Molar mass	142.956 g·mol−1
Appearance	Light pink crystals
Density	2.43
Solubility in water	insoluble
Solubility product (Ksp)	1.7×10−7[2]
Hazards
GHS labelling:
Pictograms
Signal word	Warning
Hazard statements	H302, H312
Precautionary statements	P264, P270, P280, P301+P312, P302+P352, P312, P322, P330, P363, P501
Related compounds
Related compounds	Magnesium oxalate Strontium oxalate Barium oxalate Iron(II) oxalate Iron(III) oxalate Praseodymium oxalate
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). Infobox references

Synthesis

Exchange reaction between sodium oxalate and manganese chloride:

MnCl₂ + Na₂C₂O₄ + 2 H₂O → MnC₂O₄·2H₂O + 2 NaCl

The dihydrate can also be prepared hydrothermally.^[1]

Physical properties

Manganese oxalate forms light pink crystals. The crystalline hydrates have the composition MnC₂O₄•n H₂O, where n = 2 and 3.^[7] The dihydrate forms light pink crystals of the orthorhombic system, space group P2₁2₁2₁, cell parameters a = 0.6262 nm, b = 1.3585 nm, c = 0.6091 nm, Z = 4, melts in its own crystallization water at 100 °C.^[8][9]

It does not dissolve in water, pK_sp = 6.8.

Chemical properties

Manganese oxalate is a precursor various manganese oxides, such as MnO, Mn
₂O
₃, and Mn
₃O
₄. it decomposes at 215 °C:^[10]

MnC₂O₄ → MnO + CO₂ + CO

See also

• Iron oxalate