Borate oxalate

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.

Production

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]

Properties

When heated, oxalaotoborates decompose at around 320 °C to yield a metaborate, carbon monoxide, and carbon dioxide.^[1]

List

name	chemical formula	mw	crystal system	space group	unit cell Å	volume	density	comment	CAS no	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				[4]
ammonium bis(oxalato)borate										[1]
tetramethylammonium bis(oxalato)borate	N(CH3)4B(C2O4)2									[5]
triethylammonium bis(oxalato)borate										[1]
pyridinium bis(oxalato)borate										[1]
quinolinium bis(oxalato)borate										[1]
1-ethyl-3-methylimidazolium bis(oxalate)borate (EmimBOB)								ionic liquid		[6]
1-Butyl-1-Methylpyrrolidinium bis(oxalate)borate; Bmpyr BOB	(C4H8N+)(CH3)(C4H10)[B(C2O4)2]−							ionic liquid
	[(C2H5)4N][CF3B(OCH3)(C2O4)]									[7]
	[(C2H5)4N][CF3CF2B(OCH3)(C2O4)]									[7]
	[(C2H5)4N][CF3BF(C2O4)]									[7]
	[(C2H5)4N][CF3CF2BF(C2O4)]									[7]
sodium bis(oxalato)borate, NaBOB	NaB(C2O4)2		orthorhombic	Cmcm	a 8.12756( b 10.3399 c 7.8211					[8][2]
Trihexyltetradecylphosphonium bis(oxalate)borate										[9]
	[(C6H5)4P][CF3B(OCH3)(C2O4)]	538.24	triclinic	P1	a 11.0744 b 11.5314 c 12.2196, α 73.427° β 69.395° γ 61.786° Z=2	1273.7	1.403			[7]
	[(C6H5)4P][CF3CF2B(OCH3)(C2O4)]									[7]
	[(C6H5)4P][CF3BF(C2O4)]									[7]
	[(C6H5)4P][CF3CF2BF(C2O4)]	576.22	monoclinic	C2/c	a 16.821 b 7.1612 c 21.519 β 101.981° Z=4	2535.6	1.509			[7]
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										[1]
caesium bis(oxalato)borate										[1]
thallium bis(oxalato)borate										[1]
	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]