Synthesis, Crystal Structure and Electrochemical Properties of a new methylammonium sodium decavanate salt Na3(CH6N)3[V10O28].(CH5N).14H2O

A new hybrid decavanadate Na3(CH3NH3)3[V10O28].(CH3NH2).14H2O was obtained by a simple synthesis in solution and the crystal structure was determined by single-crystal X-ray diffraction. The compound consists of decavanadate anions [V10O28]6- isolated between sodium and methylammonium cations. The UV–Visible absorption, IR spectroscopy as well as electrochemical properties were characterized. The compound crystalizes in a triclinic system (space group P-1) with the unit cell parameters: a = 10.1584(11) Å, b = 10.8123(5) Å, c = 11.1582(7) Å, α = 107.723(4)°, β = 106.811(5)°, γ = 94.238(7)°. UV–Visible absorption spectroscopy shows a strong absorption band at 300 nm. The main IR absorption bands appear at: 954 cm-1, 800 cm-1, 732 cm-1 and 580 cm-1. The electrochemical measurement of this compound shows two reversible one-electron redox process -105 mV (I-I’) and 335mV(II-II’), which was attributed to two consecutive one-electron VV → VIV reductions.