Hydrogen bonding in salts of poly-carboxylic acids, crystal structures of ethylenediammonium hydrogen tetrahydrofuran-tetracarboxylatehydrate (1 : 2 : 1 : 1) and ammonium hydrogen tetrahydrofurantetracarboxylate hydrate (3 : 1 : 1 : 2).

Hydrogen bonding in ethylenedidammonium hydrogen tetrahydrofurantetracarboxylate hydrate (1:2:1:1) and ammonium hydrogen tetrahydrofurantetracarboxylate hydrate (3:1:1:2) leads to extended ring structures. The conformations of the anions in the two salts are different because of the formation of a strong internal hydrogen bond in the ethylenediammonium salt whereas the ammonium compound has an anion pair with very short hydrogen bonds.

JOHN C BARNES ,