Text this: Various Sizes and Shapes of Mixed-Anion Fe(NH<sub>2</sub>trz)<sub>3</sub>(BF<sub>4</sub>)<sub>2−x</sub>(SiF<sub>6</sub>)<sub>x/2</sub>@SiO<sub>2</sub> Nanohybrid Particles Undergoing Spin Crossover Just Above Room Temperature