Unprecedented boat-shaped [Mo 2 O 5 (IO 3 ) 4 ] 2- polyanions induced a strong second harmonic generation response.

The first organic-inorganic hybrid guanidine molybdenyl iodate [C(NH 2 ) 3 ] 2 Mo 2 O 5 (IO 3 ) 4 ·2H 2 O was successfully synthesized via an improved moderate hydrothermal method. It features an unprecedented boat-shaped zero-dimensional [Mo 2 O 5 (IO 3 ) 4 ] 2- polyanion cluster, which induces a wide band gap, moderate birefringence and strong second harmonic generation response, indicating that it is a potential nonlinear optical material.