Four new noncentrosymmetric salt-inclusion vanadates: (AX)2Mn(VO3)2 (A/X = Rb/Cl, Cs/Cl, Cs/Br) and (CsCl)2Cu(VO3)2

Hybrid solids, made of chem. dissimilar components, have drawn much interest in advanced materials synthesis due to their structural versatility and multifunctional properties. For example, metal-org. frameworks (MOFs) have been extensively explored for their potential applications in technol. important areas including heterogeneous catalysis, gas storage, and sensors. A newly emerging area of hybrid materials includes salt-inclusion solids (SISs). These fully-inorg. SISs have structural chem. complementary to MOFs where bonding at the interface of the dissimilar lattices is directional. Recent endeavors in the area of salt-inclusion chem. have been mostly focused on creating mixed framework solids contg. transition metal phosphates, arsenates, and silicates. We have substituted previously used (XO4)3- oxyanions (X = P, As), with the fully oxidized (VO4)3- anion unveiling extremely rich structural chem. Mixed-transition-metal systems are particularly attractive because they have more potential applications in the areas coupled to catalysis, batteries, or magnetism. This is in part due to variable oxidn. states of the added transition metals as well as the unique frameworks created by the salt. Here we report 4 new noncentrosym. (NCS) salt inclusion vanadates synthesized using high temp. molten salt methods, namely (RbCl)2Mn(VO3), 1, (CsCl)2Mn(VO3)2, 2, (CsBr)2Mn(VO3)2, 3, and (CsCl)2Cu(VO3)2, 4. The structures contain ReO3-type slabs of single M-X (M = Mn, Cu, and X = Cl, Br) sheets interlinked by metavanadate chains. These compds. are isomorphous adopting two different NCS structure types where their difference becomes evident only in the propagation directions of the metavanadate chains. The acentricity of these materials is attributed to the acentric Cl-centered salt units and oriented noncentrosym. VO4 units whose polar axes point in one direction. Here we will report the synthesis and structure characterization of this family of NCS salt-inclusion vanadates.