Two novel aluminium double salts, [Al(H2O)6](SO4)NO3·2H2O, hexa-qua-alumin-ium sulfate nitrate dihydrate, (1), and [Al(H2O)6](SO4)Cl·H2O, hexaqua-aluminium sulfate chloride hydrate, (2), were obtained in the form of single crystals. Their crystal structures are each based on an octa-hedral [Al(H2O)6]3+ unit and both structures have in common one charge-balancing SO4 2- anion. The final positive charge from the aluminium(III) cation is balanced by an NO3 - or a Cl- anion for (1) and (2), respectively. Compound (1) further contains two unligated water mol-ecules while compound (2) only contains one unligated water mol-ecule. In the crystal structures, all components are spatially separated and inter-actions are mediated via medium-strong hydrogen bonding, compared to many other reported aluminium sulfates where corner-sharing of the building units is common. The two compounds represent rare cases where one aluminium(III) cation is charge-balanced by two different anions.
Keywords: aluminium; crystal structure; double salt; hydrogen bonding.
© Fredric G. Svensson 2021.