Rb3VO(O-2)(2)CO3: A Four-in-One Carbonatoperoxovanadate Exhibiting an Extremely Strong Second-Harmonic Generation Response

A nonlinear optical (NLO) carbonatoperoxovanadate, Rb3VO(O-2)(2)CO3, was synthesized through a simple solution-evaporation method in phase-pure form. Single-crystal X-ray diffraction revealed that the structure of Rb3VO-(O-2)(2)CO3 consists of important noncentrosymmetric (NCS) chromophores, that is, pi-delocalized (CO3)(2-) groups, a second-order Jahn-Teller (SOJT) distortive V5+ cation, and pi-localized distorted O-2(2-) groups, as well as charge-balancing polarizable Rb+ ions. The powder second-harmonic generation (SHG) measurements indicated that Rb3VO(O-2)(2)CO3 is phase-matchable (TypeI) and exhibits a remarkably strong SHG response circa 21.0 times that of potassium dihydrogen phosphate (KDP), which is the largest efficiency observed among carbonate NLO materials. First-principles calculation analysis suggests that the extremely large SHG response of Rb3VO(O-2)(2)CO3 is attributed to the synergistic effect of the cooperation of all the constituting NCS chromophores.