March 2006 issue
Cover illustration: Surprisingly, the single-crystal structure of ammonium hydrogenselenate(IV) has not hitherto been determined. It is isostructural with KHSeO3 and contains tetrahedral ammonium cations and trigonal-pyramidal HSeO3- anions. The structure is held together by an intricate network of weak hydrogen bonds. See Weil [Acta Cryst. (2006), E62, i38-i40].