Hydrothermal synthesis and characterization of (enH₂)_3.5[As₈V₁₄O₄₂ (PO₄)]·.2H₂O

The compound (enH₂)_3.5[As₈V₁₄O₄₂ (PO₄)]·2H₂O 1 (en = ethylenediamine) has been synthesized and characterized by means of elemental analysis, IR spectrum, ESR spectrum, XPS spectrum, TG analysis and single crystal X-ray diffraction analysis. The compound 1 crystallizes in monoclinic system, space group C2/c, a = 44.280(9) Å, b = 11.963(2) Å, c = 20.939(4) Å, β = 105.59(3), V = 10683(4) ų, Z = 8 and R₁(wR₂) = 0.0398(0.0885). The compound 1 is constructed from [As₈V₁₄O₄₂(PO₄)]^7- anions and H₂en cations linked through hydrogen bonds into a network. The [As₈V₁₄O₄₂(PO₄)]^7- cluster consists of 14 VO₅ square pyramids linked by 4 As₂O₅ handle-like units, and includes at its center an ordered PO^3-₄ anion.