title: Urea as 'deus ex machina' in giant molybdenum blue type cluster synthesis: an unusual hybrid compound with perspectives for related nano, supramolecular and extended structures.
abstract: The reaction of an aqueous solution of ammonium heptamolybdate with sodium dithionite and urea--a glue and cluster hydration shell destructing agent corresponding to its role in inclusion compound chemistry--at low pH value results in the formation of nanosized ring shaped molybdenum-oxide based clusters which in a short time get linked to chains.