Where the oxalate group is bound to the borate via oxygen, a more condensed anion is formed that balances less cations.
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.