AMoO3(IO3) (A = Na and K): Two promising optical materials via properly assembling the Λ-shaped basic building units.

• NaMoO 3 (IO 3) is the first example of molybdenum(VI) iodate with 1D chain-like structure featuring a large birefringence (0.208@1064 nm). • Both 1D [MoO 3 (IO 3)]- anionic chain in NaMoO 3 (IO 3) and 3D [MoO 3 (IO 3)]- anionic framework in γ-KMoO 3 (IO 3) are assembled from 0D Λ-shaped cis -MoO 4 (IO 3) 2 units. • The polar 3D γ-KMoO 3 (IO 3) exhibits the largest SHG response (12 × KDP) among AMoO 3 (IO 3) family as well as a high LIDT value (52 × AGS). [Display omitted] Herein, we reported two alkali metal molybdenum(VI) iodates, namely, NaMoO 3 (IO 3) and γ-KMoO 3 (IO 3) with 1D and 3D [MoO 3 (IO 3)]− anionic architectures, respectively. The novel 1D chain in NaMoO 3 (IO 3) and the 3D network in γ-KMoO 3 (IO 3) are constructed by the 0D Λ-shaped cis -[MoO 4 (IO 3) 2 ]4− building units interconnected by bridging IO 3 − anions as well as the corner-sharing of oxo anions. Importantly, the polar γ-KMoO 3 (IO 3) exhibits a very large second-harmonic generation (SHG) effect of 12 × KH 2 PO 4 (KDP) under 1064 nm laser radiation, a high laser-Induced damage threshold value (52 × AgGaS 2), and a moderate birefringence of 0.087@1064 nm, whereas the centrosymmetric NaMoO 3 (IO 3) has a large birefringence of 0.208@1064 nm. This study further proves the useful route of exploring promising optical materials via assembling the 0D basic building units into higher dimensional anionic architectures. [ABSTRACT FROM AUTHOR]