Three Polyborates with High-Symmetry [B12O24] Units Featuring Different Dimensions of Anion Groups

Three polyborates, namely, LiNa11B28O48, Li1.45Na7.55B21O36, and Li2Na4Ca7Sr2B13O27F9, were synthesized via thehigh-temperaturesolution method. All of them feature high-symmetry [B12O24] units, yet their anion groups exhibit distinct dimensions.LiNa11B28O48 features a three-dimensionalanionic structure of (3)[B28O48](infinity) framework, which is composed of three units: [B12O24], [B15O30], and [BO3]. Li1.45Na7.55B21O36 possesses a one-dimensional anionic structure of (1)[B21O36](infinity) chain consisting of [B12O24] and [B9O18] units.The anionic structure of Li2Na4Ca7Sr2B13O27F9 is composedof two zero-dimensional isolated units, namely, [B12O24] and [BO3]. The novel FBBs [B15O30] and [B21O39] are present in LiNa11B28O48 and Li1.45Na7.55B21O36, respectively. The anionicgroups in these compounds exhibit a high degree of polymerization,thereby augmenting the structural diversity of borates. And the crystalstructure, synthesis, thermal stability, and optical properties weremeticulously discussed to guide the synthesis and characterizationof novel polyborates.