Oxalic acid

Oxalic acid ;
Names:	oxalic acid; этандиовая acid; 1,2-этандиовая acid;
Formula:	H2C2O4 (anhydrous); H2C2O4 · 2H2O (dihydrate);
Molar mass:	90.034 g/mol (anhydrous); 126.064 g/mol (dihydrate);
Crystal system:	orthorhombic (α-anhydrous); a=6.548 Å, b=7.844 Å, c=6.086 Åα=90°, β=90°, γ=90°; monoclinic (β-anhydrous); a=5.33 Å, b=6.015 Å, c=5.436 Åα=90°, β=115.83°, γ=90°; monoclinic (dihydrate); a=6.12 Å, b=3.61 Å, c=12.03 Åα=90°, β=106.2°, γ=90°;
Shapes:	https://en.crystalls.info/w/uploads/media/1/12/Trapezoidal_flat_prism.json Trapezoidal flat prism https://en.crystalls.info/w/uploads/media/3/35/Deformed_tetragonal_bipyramid.json Deformed tetragonal bipyramid https://en.crystalls.info/w/uploads/media/5/52/Needle.json Needle ;
Color:	colorless;
Melting point:	189.5 °C462.65 K <br />373.1 °F <br />832.77 °R <br /> (anhydrous); 101.5 °C374.65 K <br />214.7 °F <br />674.37 °R <br /> (dihydrate);
Decomposition point:	157 °C430.15 K <br />314.6 °F <br />774.27 °R <br /> (anhydrous);
Refractive index:	1.9 (α-anhydrous); 1.895 (β-anhydrous); 1.653 (dihydrate);
Magnetic properties:	diamagnetic; χ=-6.01 · 10-5cm³/mol;
Stability:	stable (anhydrous);
Hardness:	fragile

Description

Organic compound, dibasic carbonic acid. From water solutions crystallizes as dihydrate.

Can be bought in автомагазине (как средство от ржавчины).

Keep in its original form or under several layers of varnish at average humidity and room temperature. Do not keep crystals near heaters.

TableGraph

Boric (H₃BO₃) • Disulfozirconium (H₂ZrO(SO₄)₂) • Tetrachlorauric (H[AuCl₄])

4-aminobenzoic (H₂NC₆H₄COOH) • Acetylsalicylic (C₉H₈O₄) • Ascorbic (C₆H₈O₆) • Benzoic (C₆H₅СООН) • Citric (C₃H₅O(COOH)₃) • Cyclamic (C₆H₁₃NO₃S) • Glutamic (C₅H₉NO₄) • Glycine (NH₂CH₂COOH) • Oxalic (HOOCСООН) • Phenol (C₆H₅OH) • Phthalic acid (C₈H₆O₄) • Saccarin (C₇H₅NO₃S) • Salycilic (С6Н4(OH)CООН) • Sulfamic (H₂NSO₃H) • Succinic (НООССН2СН2СООН) • Tartaric (C₄H₆O₆) • Trichloroisocyanuric (C₃Cl₃N₃O₃) • Vanillic (C₈H₈O₄)

Oxalates
Salts	Ammonium oxalate ((NH₄)₂C₂O₄) • Cobalt(II) oxalate (CoC₂O₄) • Diglycine oxalate ((NH₂CH₂COOH)₃ · H₂C₂O₄) • Neodymium oxalate (Nd₂(C₂O₄)₃) • Oxalic acid (H₂C₂O₄) • Sodium oxalate (Na₂C₂O₄) • Tris(ethylenediamine)nickel oxalate ([Ni(H₂NCH₂CH₂NH₂)₃]C₂O₄)
Dioxalatocuprates	Ammonium dioxalatocuprate(II) ((NH₄)₂[Cu(C₂O₄)₂]) • Potassium dioxalatocuprate(II) (K₂[Cu(C₂O₄)₂]) • Sodium dioxalatocuprate(II) (Na₂[Cu(C₂O₄)₂])
Trioxalatoaluminates	Potassium trioxalatoaluminate (K₃[Al(C₂O₄)₃]) • Sodium trioxalatoaluminate (Na₃[Al(C₂O₄)₃])
Trioxalatochromates	Potassium trioxalatochromate(III) (K₃[Cr(C₂O₄)₃]) • Sodium trioxalatochromate(III) (Ns₃[Cr(C₂O₄)₃])
Trioxalatocobaltates	Potassium trioxalatocobaltate(III) (K₃[Co(C₂O₄)₃])
Trioxalatoferrates	Ammonium trioxalatoferrate(III) ((NH₄)₃[Fe(C₂O₄)₃]) • Lithium trioxalatoferrate(III) (Li₃[Fe(C₂O₄)₃]) • Lithium trioxalatoferrate(III)-chloride (Li₄[Fe(C₂O₄)₃]Cl) Potassium trioxalatoferrate(III) (K₃[Fe(C₂O₄)₃]) • Potassium-sodium trioxalatoferrate(III) (K₅Na[Fe(C₂O₄)₃]₂) • Sodium trioxalatoferrate(III) (Na₃[Fe(C₂O₄)₃])
Ethers	Dimethyl oxalate ((CH₃)₂C₂O₄)

Oxalic acid
Names:	oxalic acid этандиовая acid 1,2-этандиовая acid
Formula:	H₂C₂O₄ (anhydrous) H₂C₂O₄ · 2H₂O (dihydrate)
Molar mass:	90.034 g/mol (anhydrous) 126.064 g/mol (dihydrate)
Crystal system:	orthorhombic (α-anhydrous) a=6.548 Å, b=7.844 Å, c=6.086 Åα=90°, β=90°, γ=90° monoclinic (β-anhydrous) a=5.33 Å, b=6.015 Å, c=5.436 Åα=90°, β=115.83°, γ=90° monoclinic (dihydrate) a=6.12 Å, b=3.61 Å, c=12.03 Åα=90°, β=106.2°, γ=90°
Shapes:	Trapezoidal flat prism Deformed tetragonal bipyramid Needle
Color:	colorless
Melting point:	189.5 °C462.65 K <br />373.1 °F <br />832.77 °R <br /> (anhydrous) 101.5 °C374.65 K <br />214.7 °F <br />674.37 °R <br /> (dihydrate)
Decomposition point:	157 °C430.15 K <br />314.6 °F <br />774.27 °R <br /> (anhydrous)
Refractive index:	1.9 (α-anhydrous) 1.895 (β-anhydrous) 1.653 (dihydrate)
Magnetic properties:	diamagnetic χ=-6.01 · 10^-5cm³/mol
Stability:	stable (anhydrous)
Hardness:	fragile