NaVO₂(IO₃)₂(H₂O): A Unique Layered Material Produces A Very Strong SHG Response

Abstract

The synthesis, crystal structure, and characterizations of a new noncentrosymmetric vanadyl iodate NaVO2(IO3)2(H2O), are reported. NaVO2(IO3)2(H2O) crystallizes in the polar monoclinic space group P21 (No. 4) with a = 9.114(1) Å, b = 5.2146(5) Å, c = 9.216(1) Å, and β = 111.298(8)°. It displays a unique layered structure composed of 1D right-handed helical chains of [(VO2)(IO3)2]− anions along the b-axis that are bridged by sodium(I) ions. The polarity in the structure is imparted by the alignment of the stereochemically active lone pairs of the iodate anions along the b-axis. On the basis of the powder second-harmonic generation (SHG) measurements, NaVO2(IO3)2(H2O) belongs to the phase-matchable class with a very large SHG response of approximately 20 × KH2PO4 (KDP) or about 800 × α-quartz, which is in good agreement with the results from the theoretical calculations.