Synthesis and Characterization of High-Energy -Perovskite Compounds Cs[BH] Based on Cesium Dodecahydro--Borate with Molecular Oxoanions ( = [NO], [ClO] and [ClO]).

Three novel -perovskite compounds, formulated as Cs[BH] ( = [NO], [ClO], and [ClO]), were successfully synthesized through the direct mixing of aqueous solutions containing Cs[BH] and Cs (: [NO], [ClO], [ClO]), followed by isothermal evaporation. All three compounds crystallize in the orthorhombic space group , exhibiting relatively similar unit-cell parameters (e.g., Cs[ClO][BH]: = 841.25(5) pm, = 1070.31(6) pm, = 1776.84(9) pm). The crystal structures were determined using single-crystal X-ray diffraction, revealing a distorted hexagonal -perovskite order for each. Thermal analysis indicated that the placing oxidizing anions into the 3 Cs + [BH] blend leads to a reduction in the thermal stability of the resulting -perovskites Cs[BH] as compared to pure Cs[BH], so thermal decomposition commences at lower temperatures, ranging from 320 to 440 °C. Remarkably, the examination of the energy release through DSC studies revealed that these compounds are capable of setting free a substantial amount of energy, up to 2000 J/g, upon their structural collapse under an inert-gas atmosphere (N). These three compounds represent pioneering members of the first ever -perovskite high-energy compounds based on hydro--borates.