Patent ID: 8633128

Claim:
A heteropolycompound constituted by a nickel salt of a lacunary Keggin type heteropolyanion comprising tungsten in its structure, with formula: Ni x+y/2 AW 11−y O 39−(5/2)y , zH 2 O wherein Ni is nickel; A is phosphorus, silicon or boron; W is tungsten; O is oxygen; y=0 or 2; x=3.5 if A is phosphorus; x=4 if A is silicon; x=4.5 if A is boron; and and z is a number in the range 0 to 36, and m equals 3 if A is phosphorus, m equals 4 if A is silicon and m equals 5 is A is boron, in which said heteropolycompound has no nickel atom in substitution for a tungsten atom in its structure, said nickel atoms being placed in the counter-ion position in the structure of said compound.