The cyclo-tetraphosphates of the type Co2-xCuxP4O12, where x is-an-ele
ment-of (0, 2), have been synthesized as new binary compounds. The vio
let-greenish products crystallize in the monoclinic system (C2c) group
) and the structural parameters have the values a = 1.2546-1.1799 nm,
b = 0.8092-0.8304 nm, c = 0.9565-0.9887 nm and beta = 118.50-118.70-de
grees. They were examined for potential applications as special thermo
stable pigments.