# Carbonate oxalate

The carbonate oxalates are mixed anion compounds that contain both carbonate (CO$_3$) and oxalate (C$_2$O$_4$) anions. Most compounds incorporate large trivalent metal ions, such as the rare earth elements. Some carbonate oxalate compounds of variable composition are formed by heating oxalates.

## Formation

One method to form carbonate oxalates is to heat a metal salt with ascorbic acid, which decomposes to oxalate and carbonate and combines with the metal.

## Reactions

When heated, oxalate carbonates decompose to carbon monoxide and carbonates, which form oxides at higher temperatures.

## List

| formula | name | formula weight | crystal form | space group | unit cell Å | volume Å$^3$ | density | properties |
| Sc | | | | | | | | |
| K$_4$Ti$_2$O$_2$(C$_2$O$_4$)$_3$·CO$_3$ | | | | | | | | |
| [Co*(C$_2$O$_4$)(CO$_3$)]$^{2−}$ | | | | | | | | anionic complex |
| [Co$^{III}$(CO$_3$)(C$_2$O$_4$)(NH$_3$)$_2$]- | | | | | | | | anionic complex |
| Sr[TiO(C2O4)CO$_3$] | | | | | | | | |
| [Y(H$_2$O)]$_2$(C$_2$O$_4$)(CO$_3$)$_2$ | yttrium oxalate carbonate | 421.876 | orthorhombic | C222$_1$ | a = 7.8177, b = 14.943, c = 9.4845, Z = 4 | 1108.0 | 2.526 | |
| Ba[ZrO(C$_2$O$_4$)(CO$_3$)] | | | | | | | | |
| [Ce(H$_2$O)]$_2$[(C$_2$O$_4$)$_2$(CO$_3$)]·2.5H$_2$O | | | triclinic | P1_ | a 6.329 b 8.743 c 13.000, α 105.61° β 90.55° γ 105.10° | | | |
| Pr$_4$(C$_2$O$_4$)$_4$(CO$_3$)$_2$]·3H$_2$O | catena(bis(μ$_4$-Oxalato)-(μ$_3$-oxalato)-(μ$_2$-oxalato)-bis(μ$_6$-carbonato)-bis(μ$_2$-aqua)-diaqua-tetra-praseodymium hydrate) | | triclinic | P1_ | a 6.298 b 8.673 c 12.970, α 105.42° β 90.55° γ 105.01° | | | |
| Pr$_2$(C$_2$O$_4$)(CO$_3$)$_2$ | | | | | | | | |
| Nd$_4$(C$_2$O$_4$)$_4$(CO$_3$)$_2$]·3H$_2$O | catena-[bis(μ$_4$-Oxalato)-(μ$_3$-oxalato)-(μ$_2$-oxalato)-bis(μ$_6$-carbonato)-bis(μ$_2$-aqua)-diaqua-tetra-neodymium hydrate] | | triclinic | P1_ | a 6.273(6)Å b 8.616(7)Å c 12.928(9)Å, α 105.50(6)° β 90.52(7)° γ 105.00(6)° | | | |
| (NH$_4$)$_2$[Nd$_2$(CO$_3$)(C$_2$O$_4$)$_3$(H$_2$O)]·H$_2$O | diammonium aqua—carbonato-tri—oxalato-dineodymium(III) hydrate | | triclinic | P1_ | a=8.706 b=9.530 c=10.327 α = 73.35° β = 86.90° γ = 80.50° Z=2 | 809.69 | 2.808 | |
| Eu$_4$(C$_2$O$_4$)$_4$(CO$_3$)$_2$·3H$_2$O | catena(bis(μ$_4$-Oxalato)-(μ$_3$-oxalato)-(μ$_2$-oxalato)-bis(μ$_6$-carbonato)-bis(μ$_2$-aqua)-diaqua-tetra-europium hydrate) | | triclinic | P1_ | a 6.179 b 8.464 c 12.856, α 105.13° β 90.46° γ 104.86° | | | |
| [Eu(H$_2$O)]$_2$(C$_2$O$_4$)(CO$_3$)$_2$ | | | | | | | | |
| [Gd(H$_2$O)]$_2$(C$_2$O$_4$)(CO$_3$)$_2$ | | | | | | | | |
| [Tb(H$_2$O)]$_2$(C$_2$O$_4$)(CO$_3$)$_2$ | | | | | | | | |
| [Dy(H$_2$O)]$_2$(C$_2$O$_4$)(CO$_3$)$_2$ | | | | | | | | |
| [Ho(H$_2$O)]$_2$(C$_2$O$_4$)(CO$_3$)$_2$ | | | | | | | | |
| Er$_2$(CO$_3$)$_2$(C$_2$O$_4$)(H$_2$O)$_2$ | | | monoclinic | Cm | a = 7.773, b = 14.920, c = 4.7309, β = 90.12° Z = 2 | | | |
| Pb[ZrО(C$_2$O$_4$)CO$_3$] | | | | | | | | |
| Pb$_4$(CO$_3$)$_2$(C$_2$O$_4$)(OH)$_2$ | | 535.41 | monoclinic | P2$_1$/c | a=11.8593 b=5.2486 c=9.0997 β =96.669 Z=4 | 562.58 | 6.321 | colourless |
| (NH$_4$)$_4$[Th(CO$_3$)$_2$(C$_2$O$_4$)$_2$]•0.5Н$_2$O | | | | | | | | |
| (NH$_4$)$_4$[Th(CO$_3$)$_2$(C$_2$O$_4$)$_2$]•10Н$_2$O | | | | | | | | |
| (CN$_3$H$_6$)$_3$(NH$_4$)[Th(CO$_3$)$_2$(C$_2$O$_4$)$_2$]•3Н$_2$O | | | | | | | | |
| (CN$_3$H$_6$)$_3$(NH$_4$)[Th(CO$_3$)$_3$(C$_2$O$_4$)]•1.5Н$_2$O | | | | | | | | |
| (CN$_3$H$_6$)$_3$(NH$_4$)[Th(CO$_3$)$_3$(C$_2$O$_4$)]•3Н$_2$O | | | | | | | | |
| (CN$_3$H$_6$)$_6$[Th$_2$(CO$_3$)$_5$(C$_2$O$_4$)] | hexaguandinium pentacarbonatooxalato dithorium | | | | | | | |
| (CN$_3$H$_6$)$_6$[Th$_2$(CO$_3$)$_5$(C$_2$O$_4$)$_2$]•4Н$_2$O | | | | | | | | |
| (CN$_3$H$_6$)$_6$[Th$_2$(CO$_3$)$_5$(C$_2$O$_4$)$_2$]•8Н$_2$O | | | | | | | | |
| (CN$_3$H$_6$)$_6$[Th$_2$(CO$_3$)$_4$(C$_2$O$_4$)$_3$]•14Н$_2$O | | | | | | | | |
| (CN$_3$H$_6$)$_8$[Th$_2$(CO$_3$)$_7$(C$_2$O$_4$)] | | | | | | | | |
| (CN$_3$H$_6$)$_8$[Th$_2$(CO$_3$)$_7$(C$_2$O$_4$)]•5Н$_2$O | | | | | | | | |
| (CN$_3$H$_6$)$_8$[Th$_2$(CO$_3$)$_7$(C$_2$O$_4$)]•6Н$_2$O | | | | | | | | |
| (CN$_3$H$_6$)$_8$[Th$_2$(CO$_3$)$_5$(C$_2$O$_4$)$_3$]•Н$_2$O | | | | | | | | |
| (CN$_3$H$_6$)$_{10}$[Th$_2$(CO$_3$)$_8$(C$_2$O$_4$)]•8Н$_2$O | | | | | | | | |
| Na$_4$[Th$_2$(OH)$_2$(CO$_3$)$_4$(C$_2$O$_4$)]•4Н$_2$O | | | | | | | | |
| Na$_4$[Th$_2$(OH)$_6$(CO$_3$)$_2$(C$_2$O$_4$)]•2Н$_2$O | | | | | | | | |
| Na$_8$Th(C$_2$O$_4$)$_2$(CO$_3$)$_4$ •11Н$_2$O | | | | | | | | |
| Na$_8$[Th(CO$_3$)$_5$(C$_2$O$_4$)]•11Н$_2$O | | | | | | | | |
| Na$_{10}$[Th(CO$_3$)$_5$(C$_2$O$_4$)$_2$]•11Н$_2$O | | | | | | | | |
| Na$_{10}$[Th(CO$_3$)$_5$(C$_2$O$_4$)$_2$]•16Н$_2$O | | | | | | | | |
| Na$_{10}$[Th(OH)$_2$(CO$_3$)$_3$(C$_2$O$_4$)$_3$]•8Н$_2$O | | | | | | | | |
| Na$_{10}$[Th(OH)$_2$(CO$_3$)$_3$(C$_2$O$_4$)$_3$] | | | | | | | | |
| Na$_{12}$[Th(CO$_3$)$_6$(C$_2$O$_4$)$_2$]•11Н$_2$O | | | | | | | | |
| K$_2$[Th$_2$(OH)$_2$(CO$_3$)$_3$(C$_2$O$_4$)]•2Н$_2$O | | | | | | | | |
| K$_2$[Th$_2$(OH)$_2$(CO$_3$)$_3$(C$_2$O$_4$)] | | | | | | | | |
| K$_4$[Th(CO$_3$)$_3$(C$_2$O$_4$)]•6Н$_2$O | | | | | | | | |
| K$_5$[Th$_2$(OH)(CO$_3$)$_4$(C$_2$O$_4$)2]•2Н$_2$O | | | | | | | | |
| K$_6$[Th(CO$_3$)$_4$(C$_2$O$_4$)]•8Н$_2$O | | | | | | | | |
| K$_6$[Th(CO$_3$)$_3$(C$_2$O$_4$)$_2$]•4Н$_2$O | | | | | | | | |
| K$_6$[Th$_2$(CO$_3$)$_5$(C$_2$O$_4$)$_2$]•2Н$_2$O | | | | | | | | |
| K$_6$[Th$_2$(CO$_3$)$_4$(C$_2$O$_4$)$_3$]•6Н$_2$O | | | | | | | | |
| K$_8$[Th$_2$(CO$_3$)$_5$(C$_2$O$_4$)$_3$]•13Н$_2$O | | | | | | | | |
| K$_8$[Th$_2$(CO$_3$)$_5$(C$_2$O$_4$)$_3$]•16Н$_2$O | | | | | | | | |
| K$_{10}$[Th$_2$(CO$_3$)$_7$(C$_2$O$_4$)$_2$]•8Н$_2$O | | | | | | | | |
| K$_{10}$[Th$_2$(CO$_3$)$_7$(C$_2$O$_4$)$_2$]•12Н$_2$O | | | | | | | | |
| K$_{10}$[Th$_2$(CO$_3$)$_7$(C$_2$O$_4$)$_2$]•14Н$_2$O | | | | | | | | |
| K$_{10}$[Th$_2$(CO$_3$)5(C$_2$O$_4$)4]•5Н$_2$O | | | | | | | | |
| K$_{10}$[Th$_2$(CO$_3$)5(C$_2$O$_4$)4]•7Н$_2$O | | | | | | | | |
| (NH$_4$)(CN$_3$H$_6$)$_3$[(UO$_2$)$_2$(CO$_3$)(C$_2$O$_4$)$_2$(C$_3$H$_4$N$_2$O$_2$)] · H$_2$O | | | | | | | | |
| (CN$_3$H$_6$)$_4$[(UO$_2$)$_2$(CO$_3$)(C$_2$O$_4$)$_2$(C$_5$H$_8$N$_2$O$_2$)] · 1.5H$_2$O | guanidonium μ-carbonate μ-ethylmethylgyoximatedioxylatediuranylate sesquihydrate | | monoclinic | P2$_1$ | a=6.909 b=15.794 c=30.064 β=96.720° Z=4 | 3258 | 2.383 | red plates |
| (CN$_3$H$_6$)$_4$[(UO$_2$)$_2$(CO$_3$)(C$_2$O$_4$)$_2$(C$_6$H$_8$N$_2$O$_2$)] · 3H$_2$O | | | | | | | | |
| (NH$_4$)(CN$_3$H$_6$)$_4$[(UO$_2$)$_2$(CO$_3$)(C$_2$O$_4$)$_2$(C$_6$H$_4$N$_2$O$_2$)] · H$_2$O | | | | | | | | |
| (CN$_3$H$_6$)$_4$[(UO$_2$)$_2$(C$_6$H$_8$N$_2$O$_2$)(CO$_3$)(C$_2$O$_4$)$_2$] · (C$_6$H$_{10}$N$_2$O$_2$) · 2H$_2$O | guanidinium (3-methyl-1,2-cyclopenadionedioxime)dioxalato (μ-3-methyl-1,2-cyclopenadionedioxato) μ-carbonatodiuranylate dihydrate | | triclinic | P1_ | a=9.2474 b=14.8562 c=16.8917 α = 68.504° β = 77.721° γ = 89.792° Z=2 | 2102.7 | 2.108 | red |
| (CN$_3$H$_6$)$_4$[(UO$_2$)$_2$(CO$_3$)(C$_2$O$_4$)$_2$(C$_7$H$_{10}$N$_2$O$_2$)] · H$_2$O | | | | | | | | |
| NH$_4$(CN$_3$H$_6$)$_3$[(UO$_2$)$_2$(C$_7$H$_{10}$N$_2$O$_2$)(CO$_3$)(C$_2$O$_4$)$_2$] · 2H$_2$O | ammonium guanidinium dioxalato (μ-3-methyl-1,2-cyclopenadionedioxato) μ-carbonatodiuranylate dihydrate | | orthorhombic | P2$_1$2$_1$2$_1$ | a=9.904 b=17.400 c=18.757 Z=4 | 3232.2 | 2.393 | red |
| (CN$_3$H$_6$)$_4$[(UO$_2$)$_2$(CO$_3$)(C$_2$O$_4$)$_2$(C$_6$H$_{10}$N$_2$O$_2$)] · H$_2$O | guanidinium dioxalato μ-diethylglyoximato μ-carbonatodiuranylate monohydrate | 1176.59 | monoclinic | P2$_1$/n | a=7.6140 b=15.4388 c=28.010 β=95.99° Z=4 | 3274.6 | 2.387 | orange |
| (CN$_3$H$_6$)$_2$(C$_2$H$_2$N$_2$)[(UO$_2$)$_2$(CO$_3$)(C$_2$O$_4$)$_2$(C$_6$H$_{10}$N$_2$O$_2$)] · 3H$_2$O | guanidinium ethylenediammonium dioxalato μ-diethylglyoximato μ-carbonatodiuranylate monohydrate | | | | | | | orange |
| [C(NH$_2$)$_3$]$_{10}$[(UO$_2$)$_6$(μ3-O)$_2$(μ2-OH)$_2$(C$_2$O$_4$)$_4$(CO$_3$)$_4$]· 2H$_2$O | | 2913.21 | triclinic | P1_ | a=11.5919 b=11.7868 c=13.3545 α = 102.637° β = 93.278° γ = 95.273° Z=1 | 1759.7 | 2.749 | yellow |
| Pu | Plutonium(III) oxalate carbonate | | | | | | | |