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Lead(II) oxalate

Identifiers
CAS Number	814-93-7
3D model (JSmol)	Interactive image
ChemSpider	55161
ECHA InfoCard	100.011.284
EC Number	212-413-5
PubChem CID	61218
UNII	642NGP7E5U
UN number	2291
CompTox Dashboard (EPA)	DTXSID70883589
InChI InChI=1S/C2H2O4.Pb/c3-1(4)2(5)6;/h(H,3,4)(H,5,6);/q;+2/p-2
SMILES C(=O)(C(=O)).
Properties
Chemical formula	PbC2O4
Molar mass	295.219
Appearance	White Powder
Density	5.28 g/cm
Melting point	327.4 °C (621.3 °F; 600.5 K)
Boiling point	1,740 °C (3,160 °F; 2,010 K)
Solubility in water	0.0091 g/100 ml (25 °C)
Thermochemistry
Std molar entropy (S298)	146.0216 J
Std enthalpy of formation (ΔfH298)	-851.444 kJ/mol
Hazards
Occupational safety and health (OHS/OSH):
Main hazards	Nephrotoxin, Reproductive Toxin, Neurotoxin, IARC Carcinogen, Birth Defects, Highly Toxic
GHS labelling:
Pictograms
Signal word	Danger
Hazard statements	H302, H332, H360, H373, H410
Precautionary statements	P201, P202, P260, P261, P264, P270, P271, P273, P281, P301+P312, P304+P312, P304+P340, P308+P313, P312, P314, P330, P391, P405, P501
NIOSH (US health exposure limits):
PEL (Permissible)	0.05 mg/m3, as Pb
Except where otherwise noted, data are given for materials in their standard state (at 25 °C , 100 kPa). Infobox references

Lead(II) oxalate is an organic compound with the formula PbC₂O₄. It is naturally found as a heavy white solid.

Preparation

This compound is commercially available. It may be prepared by the metathesis reaction between lead(II) nitrate and sodium oxalate:

Pb(aq) + C₂O₄ → PbC₂O₄ (s)

A dihydrate may be formed with water solutions. But the dihydrate dehydrates in air:

(PbC₂O₄•2H₂O (s) → (PbC₂O₄ (s) + 2H₂O (g)

The trihydrate (PbC₂O₄•3H₂O) can be made by reacting a solution of lead(II) carbonate in perchloric acid with oxalylhydroxamic acid.

Properties

As well as an anhydrous form, a monohydrate (PbC₂O₄•H₂O), a dihydrate (PbC₂O₄•2H₂O) and a trihydrate (PbC₂O₄•3H₂O) are known. The dihydrate is from the orthorhombic crystal system, with space group Pnam (number 62), with unit cell dimensions: a = 9.053 Å b = 8.036 Å and c = 7.834 Å. The unit cell volume is 569.8 Å with four formula per cell, giving a density of 3.860 g/cm

The trihydrate has triclinic crystals with space group P1 and unit cell dimensions and angles: a = 6.008 Å, b=6.671 Å, c=8.493 Å, α=74.70°, β=74.33°, and γ=80.98°. The unit cell volume is 314.41 Å with two formula per unit cell. Density is 3.69 g/cm.

Solubility

Lead(II) oxalate is insoluble in water. Its solubility is increased in presence of excess oxalate anions, due to the formation of the Pb(C₂O₄)₂ complex ion.

References

1. "Lead(II) Oxalate". Chemistry Reference. http://www.chemistry-reference.com/q_compounds.asp?CAS=814-93-7.
2. "Lead Oxalate". American Elements: The World's Manufacturer of Engineered & Advanced Materials http://www.americanelements.com/pboxl.html.
3. Grases, F.; Ruiz, J.; Costa-Bauzá, A. (1993). "Studies on Lead Oxalate Crystalline Growth". Journal of Colloid and Interface Science. 155 (2): 265–270. doi:10.1006/jcis.1993.1035.
4. ^ Boldyreva, E. V.; Naumov, D. Y.; Podberezskaya, N. V.; Virovets, A. V. (15 November 1993). "Structure of lead(II) oxalate dihydrate". Acta Crystallographica Section C: Crystal Structure Communications. 49 (11): 1882–1884. doi:10.1107/S0108270193004652.
5. ^ Sheng-Hua, Huang; Ru-Ji, Wang; Mak, Thomas C. W. (April 1990). "Crystal structures of isomorphous cadmium(II) and lead(II) oxalate trihydrates". Journal of Crystallographic and Spectroscopic Research. 20 (2): 99–104. doi:10.1007/BF01160959.
6. Kolthoff, I.M.; Perlich, R. W.; Weiblen, D. (1942). "The Solubility of lead Sulfate and of Lead Oxalate in Various Media". Journal of Physical Chemistry. 46 (5): 561. doi:10.1021/j150419a004.

• Lead(II) compounds
• Oxalates