NEW POLYOXOTANTALATE SALT Na<sub>8</sub>[Ta<sub>6</sub>O<sub>19</sub>]·24.5H<sub>2</sub>O and its properties
The interaction of Ta2O5 with sodium hydroxide at 400°C yields Na8[Ta6O19], which can be recrystallized from an aqueous solution in the form of Na8[Ta6O19]·24.5H2O. The complex is characterized by IR spectroscopy, thermogravimetry, powder XRD, and single crystal XRD: hexagonal system, P63 space group, a = 12.3622(2) Å, c = 31.4305(7) Å, V = 4159.81(13) Å3, dx = 3.217 g/cm3, R = 0.0195.