Yttrium oxalate

Yttrium oxalate is an inorganic compound, a salt of yttrium and oxalic acid with the chemical formula YTemplate:Sub(CTemplate:SubOTemplate:Sub)Template:Sub. The compound does not dissolve in water and forms crystalline hydrates—colorless crystals.

Synthesis

Precipitation of soluble yttrium salts with oxalic acid:

$\mathrm{𝟤}𝖸𝖢{𝗅}_{\mathrm{𝟥}}\mathsf{+}\mathrm{𝟥}{𝖧}_{\mathrm{𝟤}}{𝖢}_{\mathrm{𝟤}}{𝖮}_{\mathrm{𝟦}}\stackrel{}{\to }{𝖸}_{\mathrm{𝟤}}\mathsf{(}{𝖢}_{\mathrm{𝟤}}{𝖮}_{\mathrm{𝟦}}{\mathsf{)}}_{\mathrm{𝟥}}\mathsf{\downarrow }\mathsf{+}\mathrm{𝟨}𝖧𝖢𝗅$

Properties

Yttrium oxalate is highly insoluble in water and converts to the oxide when heated. Yttrium oxalate forms crystalline hydrates (colorless crystals) with the formula YTemplate:Sub(CTemplate:SubOTemplate:Sub)Template:Sub•n HTemplate:SubO, where n = 4, 9, and 10.

Decomposes when heated:

${𝖸}_{\mathrm{𝟤}}\mathsf{(}{𝖢}_{\mathrm{𝟤}}{𝖮}_{\mathrm{𝟦}}{\mathsf{)}}_{\mathrm{𝟥}}\stackrel{700^{o}C}{\to }{𝖸}_{\mathrm{𝟤}}{𝖮}_{\mathrm{𝟥}}\mathsf{+}\mathrm{𝟥}𝖢{𝖮}_{\mathrm{𝟤}}\mathsf{+}\mathrm{𝟥}𝖢𝖮$

The solubility product of yttrium oxalate at 25 °C is 5.1 × 10⁻³⁰.

The trihydrate YTemplate:Sub(CTemplate:SubOTemplate:Sub)Template:Sub•3HTemplate:SubO is formed by heating more hydrated varieties at 110 °C.

YTemplate:Sub(CTemplate:SubOTemplate:Sub)Template:Sub•2HTemplate:SubO, which is formed by heating the decahydrate at 210 °C) forms monoclinic crystals with unit cell dimensions a=9.3811 Å, b=11.638 Å, c=5.9726 Å, β=96.079°.

Related

Several yttrium oxalate double salts are known containing additional cations. Also a mixed-anion compound with carbonate is known.

formula	name	formula weight	crystal form	space group	unit cell Å	volume Å3	properties	references
NH4Y(C2O4)2.H2O	Ammonium yttrium oxalate monohydrate		monoclinic	P2/n	a=9.18 b=6.09 c=7.89 β=90.2 Z=2
[C6N2H16]0.5[Y(H2O)(C2O4)2]·2H2O		377.1	triclinic	PTemplate:Overbar	a = 8.229, b = 9.739, c = 9.754, α = 60.74, β = 72.36, γ = 84.67°, Z = 2	648.5	density 1.931
[C5N2H12] [Y(C2O4)2]		365.1	monoclinic	Cc	a = 11.552, b = 17.168, c = 8.719, β = 130.64°, Z = 2	1312.1	density 1.848
C5NH6Y(C2O4)2•3H2O	Pyridinium yttrium oxalate trihydrate
[Y(H2O)]Na(C2O4)2.3H2O	yttrium sodium oxalate tetrahydrate	360.005	monoclinic	Pc	a=8.623 b=8.6310 c=14.896 β=102.848 Z=4	1080.9
YK(C2O4)2.4H2O	Yttrium potassium oxalate tetrahydrate		tetragonal	I41/a	Z = 4 a = 11.4612, c = 8.9040	1169.6
Y(H2O)Cs(C2O4)2	Caesium yttrium oxalate monohydrate		monoclinic	P2/n	a = 8.979, b = 6.2299, c = 8.103, β = 90.05°	453.3
RbLn(C2O4)2•3H2O	Rubidium yttrium oxalate trihydrate
[Y(H2O)]2(C2O4)(CO3)2	yttrium oxalate carbonate	421.876	orthorhombic	C2221	a = 7.8177, b = 14.943, c = 9.4845, Z = 4	1108.0	density 2.526