Synthesis and structure of [NH4](4)H[(PMo8V4V2O42)-V-IV-O-V].24H(2)O

[NH4](4)H[(PMo8V4V2O42)-V-IV-O-V] . 24H(2)O has been hydrothermally synthesized from ammonium vanadate and sodium molybdate in aqueous solution by adding phosphorous acid, and its structure determined by single crystal X-ray analysis. The heteropoly molybdovanadophosphate anion is a bicapped 'pseudo-Keggin' polyanion, two vanadium atoms are distributed at two 'capping' metal atom positions and other four vanadium atoms randomly distributed at eight metal atom positions. (C) 1998 Elsevier Science Ltd. All rights reserved.