The borate oxalates are chemical compounds containing borate and oxalate anions. Where the oxalate group is bound to the borate via oxygen, a more condensed anion is formed that balances less cations. These can be termed boro-oxalates, bis(oxalato)borates, or oxalatoborates or oxalate borates. The oxalatoborates are heterocyclic compounds with a ring containing -O-B-O-. Bis(oxalato)borates are spiro compounds with rings joined at the boron atom.
Oxalatoborates are used or for research in lithium-ion battery electrolytes and for supercapacitors.
Oxalatoborates have been produced by heating boric acid, oxalic acid and one of a metal oxalate, a metal carbonate or an amine in boiling benzene.[1]
When heated, oxalaotoborates decompose at around 320 °C to yield a metaborate, carbon monoxide, and carbon dioxide.
| name | chemical formula | mw | crystal system | space group | unit cell Å | volume | density | comment | CASno | references |
|---|---|---|---|---|---|---|---|---|---|---|
| Lithium bis(oxalate)borate, LiBOB | LiB(C2O4)2 | 193.8 | orthorhombic | Pnma | a 6.3635 b 7.5998 c 13.1715 | 244761-29-3 | [2] | |||
| lithium difluoro (oxalate) borate, LiDFOB | LiBF2(C2O4) | 143.8 | orthorhombic | Cmcm | a = 6.2623, b = 11.437, c = 6.3002, Z = 4 | 451.22 | 409071-16-5 | [3] [4] | ||
| lithium difluoro (oxalate) borate dihydrate | LiBF2(C2O4)•2H2O | monoclinic | P21/c | a = 9.5580, b = 12.7162, c = 5.4387, β =106.247 Z = 4 | 634.63 | |||||
| ammonium bis(oxalato)borate | ||||||||||
| tetramethylammonium bis(oxalato)borate | N(CH3)4B(C2O4)2 | [5] | ||||||||
| triethylammonium bis(oxalato)borate | ||||||||||
| pyridinium bis(oxalato)borate | ||||||||||
| quinolinium bis(oxalato)borate | ||||||||||
| 1-ethyl-3-methylimidazolium bis(oxalate)borate (EmimBOB) | ionic liquid | [6] | ||||||||
| 1-Butyl-1-Methylpyrrolidinium bis(oxalate)borate; Bmpyr BOB | (C4H8N+)(CH3)(C4H10)[B(C<sub>2</sub>O<sub>4</sub>)<sub>2</sub>]− | ionic liquid | ||||||||
| [(C<sub>2</sub>H<sub>5</sub>)<sub>4</sub>N][CF<sub>3</sub>B(OCH<sub>3</sub>)(C<sub>2</sub>O<sub>4</sub>)] | [7] | |||||||||
| [(C<sub>2</sub>H<sub>5</sub>)<sub>4</sub>N][CF<sub>3</sub>CF<sub>2</sub>B(OCH<sub>3</sub>)(C<sub>2</sub>O<sub>4</sub>)] | ||||||||||
| [(C<sub>2</sub>H<sub>5</sub>)<sub>4</sub>N][CF<sub>3</sub>BF(C<sub>2</sub>O<sub>4</sub>)] | ||||||||||
| [(C<sub>2</sub>H<sub>5</sub>)<sub>4</sub>N][CF<sub>3</sub>CF<sub>2</sub>BF(C<sub>2</sub>O<sub>4</sub>)] | ||||||||||
| sodium bis(oxalato)borate, NaBOB | NaB(C2O4)2 | orthorhombic | Cmcm | a 8.12756(b 10.3399 c 7.8211 | [8] | |||||
| Trihexyltetradecylphosphonium bis(oxalate)borate | [9] | |||||||||
| [(C<sub>6</sub>H<sub>5</sub>)<sub>4</sub>P][CF<sub>3</sub>B(OCH<sub>3</sub>)(C<sub>2</sub>O<sub>4</sub>)] | 538.24 | triclinic | P | a 11.0744 b 11.5314 c 12.2196, α 73.427° β 69.395° γ 61.786° Z=2 | 1273.7 | 1.403 | ||||
| [(C<sub>6</sub>H<sub>5</sub>)<sub>4</sub>P][CF<sub>3</sub>CF<sub>2</sub>B(OCH<sub>3</sub>)(C<sub>2</sub>O<sub>4</sub>)] | ||||||||||
| [(C<sub>6</sub>H<sub>5</sub>)<sub>4</sub>P][CF<sub>3</sub>BF(C<sub>2</sub>O<sub>4</sub>)] | ||||||||||
| [(C<sub>6</sub>H<sub>5</sub>)<sub>4</sub>P][CF<sub>3</sub>CF<sub>2</sub>BF(C<sub>2</sub>O<sub>4</sub>)] | 576.22 | monoclinic | C2/c | a 16.821 b 7.1612 c 21.519 β 101.981° Z=4 | 2535.6 | 1.509 | ||||
| Lithium difluoro(oxalato)borate tetramethylene sulfone disolvate | Li+•C2BF2O4−•2C4H8O2S | monoclinic | P21/n | a = 13.9005 b = 5.8917 c = 19.9627 β = 106.010 Z=4 | 1571.48 | 1.623 | colourless | [10] | ||
| potassium boro-oxalate | K(C2O4)(BO2)2•2H2O | 248.77 | triclinic | P1 | a=6.3508 b=7.0095 c=10.590 α=93.798 β=101.424 γ=100.196 | 452.3 | 1.827 | NLO 1×KDP; stable to 187 °C | [11] | |
| rubidium bis(oxalato)borate | ||||||||||
| caesium bis(oxalato)borate | ||||||||||
| thallium bis(oxalato)borate | ||||||||||
| Pb6O2(BO3)2(C2O4) | 740.39 | orthorhombic | Cmcm | a=18.0445 b=6.6225 c=11.4682 Z=8 | 1370.45 | 7.177 | band gap 3.60 eV | [12] | ||