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The structural transformation of vanadium phosphate hemihydrate, VOHPO 4 ‚ 1 / 2 H 2 O, into ammonium vanadyl pyrophosphate, (NH 4 ) 2 [(VO) 3 (P 2 O 7 ) 2 ], was studied by XRD and spectroscopic methods such as FTIR and Raman spectroscopy. The reaction was carried out at 673 K in the presence of the ammoxidation feed (toluene, oxygen (air), ammonia, and water vapor), proceeding through an intermediate crystalline phase. The main product of the transformation was R-. Both materials are characterized by the orthorhombic space group Pna2 1 and an intersecting tunnel structure. Apart from R-(NH 4 ) 2 [(VO) 3 (P 2 O 7 ) 2 ], a vanadium-rich phase was formed according to the stoichiometry which is probably a mixed valent vanadium oxide. The structural transformation proceeded also in the same direction without participation of the aromatic substrate. The reaction of VOHPO 4 ‚ 1 / 2 H 2 O carried out only under an ammonia/ oxygen (air) flow led to the generation of R-(NH 4 ) 2 [(VO) 3 (P 2 O 7 ) 2 ] as well, but to a minor degree. An XRD-amorphous material was obtained, being the main phase. The treatment of the hemihydrate with an ammonia/nitrogen flow generated an XRD-amorphous product and a deep reduction of V IV w V III proceeded.

Die Reaktion von Phosphor(V)‐sulfid mit überschüssigem Pyridin führt zum Pentathiodiphosphorsäure‐P, P'‐bis(pyrididiumbetain), [2 Py · P2S5], das in pyridinischer Lösung mit Phosphoroxidchlorid zum Monothiophosphorsäurechlorid‐pyrididiumbetain, [Py · POSCl], und mit Phosphorsulfidchlorid zum Dithiophosphorsäurechlorid‐pyrididiumbetain [Py · PS2Cl], reagiert. Bei der in Gegenwart von Pyridin durchgeführten Reorganisationsreaktion zwischen P4S10 und POCl3, die zu kondensierten Thio‐oxo‐phosphorylchloriden führt, treten [2 Py · P2S5] und [Py · POSCl] offenbar als reaktionsfähige Zwischenprodukte auf.

A new and simple preparation method for fluoride-templated tetranuclear vanadium phosphonate cage compounds, M(n+)[(V2O3)2(RPO3)4

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