Boro-oxalates, bis(oxalato)borates, or oxalatoborates are chemical compounds where an oxalate group is bound to a borate group via oxygen, forming a condensed anion. The oxalatoborates are heterocyclic compounds with a ring containing -O-B-O-C-C-. Bis(oxalato)borates are spiro compounds with two rings joined at the boron atom.
Oxalatoborates are used for research in lithium-ion battery electrolytes and for supercapacitors.
The borate oxalates are chemical compounds containing separate borate and oxalate anions. Compared to oxalatoborates, these are of little importance. Production Oxalatoborates have been produced by heating boric acid, oxalic acid and a metal oxalate, a metal carbonate or an amine in boiling benzene with continuous removal of water via azeotropic distillation.
Properties When heated, oxalatoborates decompose at around 320 °C to yield a metaborate, carbon monoxide, and carbon dioxide.
List NameChemical formulaMolecular weightCrystal systemSpace groupUnit cell (Å)VolumeDensityCommentsReferencesLithium bis(oxalate)borate, LiBOBLiB(C2O4)2193.8orthorhombicPnmaa 6.3635 b 7.5998 c 13.1715lithium difluoro (oxalate) borate, LiDFOBLiBF2(C2O4)143.8orthorhombicCmcma = 6.2623, b = 11.437, c = 6.3002, Z = 4451.22lithium difluoro (oxalate) borate dihydrateLiBF2(C2O4)•2H2OmonoclinicP21/ca = 9.5580, b = 12.7162, c = 5.4387, β =106.247 Z = 4634.63ammonium bis(oxalato)boratetetramethylammonium bis(oxalato)borateN(CH3)4B(C2O4)2triethylammonium bis(oxalato)boratepyridinium bis(oxalato)boratequinolinium bis(oxalato)borate1-ethyl-3-methylimidazolium bis(oxalate)borate (EmimBOB)ionic liquid1-Butyl-1-Methylpyrrolidinium bis(oxalate)borate; Bmpyr BOB(C4H8N+)(CH3)(C4H10)[B(C2O4)2]−ionic liquid[(C2H5)4N][CF3B(OCH3)(C2O4)][(C2H5)4N][CF3CF2B(OCH3)(C2O4)][(C2H5)4N][CF3BF(C2O4)][(C2H5)4N][CF3CF2BF(C2O4)]sodium bis(oxalato)borate, NaBOBNaB(C2O4)2orthorhombicCmcma 8.12756( b 10.3399 c 7.8211Trihexyltetradecylphosphonium bis(oxalate)borate[(C6H5)4P][CF3B(OCH3)(C2O4)]538.24triclinicPa 11.0744 b 11.5314 c 12.2196, α 73.427° β 69.395° γ 61.786° Z=21273.71.403[(C6H5)4P][CF3CF2B(OCH3)(C2O4)][(C6H5)4P][CF3BF(C2O4)][(C6H5)4P][CF3CF2BF(C2O4)]576.22monoclinicC2/ca 16.821 b 7.1612 c 21.519 β 101.981° Z=42535.6 1.509Lithium difluoro(oxalato)borate tetramethylene sulfone disolvateLi+•C2BF2O4−•2C4H8O2SmonoclinicP21/na = 13.9005 b = 5.8917 c = 19.9627 β = 106.010 Z=41571.481.623colourlessrubidium bis(oxalato)boratecaesium bis(oxalato)boratethallium bis(oxalato)borate Borate oxalatespotassium boro-oxalateK(C2O4)(BO2)2•2H2O248.77triclinicP1a=6.3508 b=7.0095 c=10.590 α=93.798 β=101.424 γ=100.196 452.31.827NLO 1.56×KDP; stable to 187 °CPb6O2(BO3)2(C2O4)740.39orthorhombicCmcma=18.0445 b=6.6225 c=11.4682 Z=81370.457.177band gap 3.60 eV
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