Patent ID: 8754154

Claim:
A compound of the formula (III-1) or of the formula (III-2) [(A-H) + ] m [M m+ (HPO 4 2− ) m ] (III-1) [(A-H) + ] m [M m+ (P 2 O 7 4− ) m/2 ] (III-2) where (A-H) + is a radical of the formula (IV) in which X is H, CN, C(NH)NH 2 , C(O)NH 2 , C(NH)NHCN, or a condensation product thereof; each M is independently Ca, Mg, Zn or Al; and m is 2 or 3, characterized in that the molar ratio of (A-H) + to phosphorus is less than 1.1.