Centrosymmetric (NH4)2SbCl(SO4)2 and Non-centrosymmetric (NH4)SbCl2(SO4): Synergistic Effect of Hydrogen-Bonding Interactions and Lone-Pair Cations on the Framework Structures and Macroscopic Centricities

Two new antimony sulfate chlorides named (NH4)2SbCl(SO4)2 and (NH4)SbCl2(SO4) were successfully synthesized through solvent-free synthesis method. (NH4)2SbCl(SO4)2 exhibits a three-dimensional framework constructed of [SbCl(SO4)2]2– chains and NH4+ ions. And the NH4+ cations play the role of charge balance and provide the hydrogen bond constructed with oxygen atoms. (NH4)SbCl2(SO4) shows a two-dimensional layer structure that is composed of the regularly stacked [SbCl2(SO4)]− chains via hydrogen-bonding interactions. Both of the titled compounds possess the same chemical composition and the similar Sb–Cl–SO4 chains, while hydrogen-bonding interactions and lone-pair cations play the synergistic effect on the framework structures and macroscopic centricities resulting in that the (NH4)2SbCl(SO4)2 is centrosymmetric and the (NH4)SbCl2(SO4) is non-centrosymmetric (NCS). Powder second harmonic generation (SHG) measurements indicated that the NCS compound (NH4)SbCl2(SO4) is type I phase-matchable and exhibits SHG responses of ∼1.7 times that of KH2PO4.