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.

Automated summary

Three polyborates, LiNa11B28O48, Li1.45Na7.55B21O36, and Li2Na4Ca7Sr2B13O27F9, were synthesized via high-temperature solution method. They exhibit high-symmetry [B12O24] units, but differ in dimensions of their anion groups. LiNa11B28O48 has a three-dimensional anionic structure of (3)[B28O48](infinity) framework, composed of [B12O24], [B15O30], and [BO3] units. Li1.45Na7.55B21O36 has a one-dimensional anionic structure of (1)[B21O36](infinity) chain consisting of [B12O24] and [B9O18] units. Li2Na4Ca7Sr2B13O27F9 has a zero-dimensional anionic structure, composed of isolated units of [B12O24] and [BO3]. The anionic groups in these compounds have high polymerization, enhancing the structural diversity of borates. The crystal structure, synthesis, thermal stability, and optical properties are discussed in detail for guiding the synthesis and characterization of novel polyborates.