Abstract
Abstract Using solution evaporation techniques, we succeeded in preparation of new members essentially extending the layered copper hydrogen selenite family, ( AX )[Cu(HSeO 3 ) 2 ] with A = Na, K, Rb, Cs, and NH 4 , and X = Cl and Br. Bromides and chlorides are isostructural in the family of described new compounds crystallizing in three different structure types. (Na X )[Cu(HSeO 3 ) 2 ] and (K X )[Cu(HSeO 3 ) 2 ] ( X = Cl, Br) are monoclinic, whereas ( AX )[Cu(HSeO 3 ) 2 ] ( A = NH 4 , Rb, Cs; X = Cl, Br) are orthorhombic. Upon the enlargement of the A + ionic radii inserted in the interlayer between the neighboring [Cu(HSeO 3 ) 2 ] slabs, the effective distance is increasing and results in essential elongation of the apical Cu- X ( X = Cl, Br) distances. Three different types of CuO 4 X n ( n = 0–2) polyhedra are formed. The observed trend is an interesting example of the chemical tuning of the Cu 2+ coordination environments.