The phase structure, thermodynamic properties, and dissolution behavior of Ca <sub>5</sub> Mg <sub>4</sub> V <sub>6</sub> O <sub>24</sub>
Guishang Pei, Junyi Xiang, In‐Ho Jung, Mengjiao Jiao, Zhuoyang Li, Xuewei Lv
Abstract
Abstract A Ca 5 Mg 4 V 6 O 24 compound was synthesized through solid‐state roasting routes under an air atmosphere, and its crystal structure and thermodynamic properties were determined using various methods. The cell parameters of Ca 5 Mg 4 V 6 O 24 indicate that it crystallizes in cubic space group Ia 3 d with the unit cell parameters a = 12.442 ± 0.001 Å. X‐ray photoelectron spectroscopy also confirmed that the vanadium element in the Ca 5 Mg 4 V 6 O 24 sample is present in the +5 state. The melting of Ca 5 Mg 4 V 6 O 24 was detected at 1442 K. The molar heat capacity (374 J mol K −1 ) and entropy (688.2 J mol K −1 ) of Ca 5 Mg 4 V 6 O 24 at 298.15 K were determined using physical properties measurement system, and simultaneous thermal analyzer for the first time. The solubility of Ca 5 Mg 4 V 6 O 24 in water at different temperatures was measured and its dissolution behavior in sulfuric acid and kinetics was experimentally established.