Patent ID: 7410536

Claim:
An oxidation-stable iron oxide pigment comprising Fe(II), said FE(II) having a content of at least 5% by weight calculated as FeO; and a coating, said coating consists of an organic coating composed of one or more compounds of the general formula (I) R—(COOX) n (1) wherein R is a saturated or unsaturated linear or branched aliphatic radical having 1 to 15 carbon atoms which is optionally substituted one or more times by halogen and/or NH 2 and/or OH and/or NHR 1 and/or NR 1 2 and/or OR 1 , or is an alicyclic or aromatic radical having 4 to 26 carbon atoms which is optionally substituted one or more times by halogen and/or NH 2 and/or OH and/or NHR 1 and/or NR 1 2 and/or OR 1 and/or R 1 , R 1 being a saturated or unsaturated linear or branched optionally substituted aliphatic radical having in each case 1 to 10 carbon atoms or an optionally substituted alicyclic or aromatic radical having in each case 6 to 10 carbon atoms; X is hydrogen, alkali metal, NR 2 4 , R 2 being H or a linear or branched aliphatic, alicyclic or aromatic radical, or ½ alkaline earth metal, ⅓ Al or ⅓ Fe and n is an integer from 1 to 10; wherein the iron oxide pigment has an oxidation stability in the oxidation stability test of ≧10° C. as compared with an uncoated iron oxide pigment.