| Abstract: | Reactions at the Metallic Substrate: Single Crystals of Ni(NH3)2V2F8 Except for the main product (NH4)2TaF7] and some Ni(NH3)6]TaF6]2, the new light green Ni(NH3)2V2F8 is obtained by the reaction of (NH4)F with tantalum and vanadium (molar ratio of (NH4)F : Ta : V = 36 : 6 : 1) at 400 °C in a sealed Monel ampoule (Cu32Ni68). The crystal structure (orthorhombic, Fmmm, Z = 4, a = 752.9(1), b = 762.9(1), c = 1307.6(2) pm) is related to that of (NH4)VF4]. According to {Ni(NH3)2}0,5VF4], corrugated layers of vertex-connected octahedra VF4/2F2/1] are stacked in the 001] direction. Between these layers trans-{Ni(NH3)2} units are inserted so that Ni2+ enhances its coordination number to 6 by two times two F– from the layers above and below. |
