A new family of crystalline metal oxide compositions have been synthesized. These compositions are described by the empirical formula: AnMM'xMyOp where A is an alkali metal cation, ammonium ion and mixtures thereof, M is niobium or tantalum, M' is tungsten, molybdenum, or mixtures thereof. M' is vanadium, tantalum, niobium, titanium, tin indium, gallium, aluminum, bismuth, antimony, tellurium and mixtures thereof. M' is an optional metal. These compositions are characterized by having an x-ray diffraction pattern having at least one peak at a d spacing of about 3.9Å. A hydrothermal synthesis procedure as well as hybrocarbon conversion processes using the composition are also disclosed.