Patent ID: 7387672

Claim:
Oxidation-stable iron oxide pigment having an iron(II) content of at least 5% by weight, calculated as FeO, and having an organic coating, characterized in that the coating is composed of one or more organic compounds of the general formula (I) XO a R 3 b (OR 2 ) c R 1 d (I) Wherein X is Si, Sn, Ti, Zr, P or S; R 3 is Cl, Br, NH 2 , or OM, M being hydrogen, an ammonium compound, an alkali metal or ½ alkaline earth metal or ⅓ Al or ⅓ Fe, and each of R 2 and R 1 are independent of one another, 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 and/or NR 2 and/or OR, or is an alicyclic radical having 4 to 26 carbon atoms or is an aromatic radical having 6 to 26 carbon atoms which is optionally substituted one or more times by halogen and/or NH 2 and/or OH and/or NHR and/or NR 2 and/or OR and/or R, R being a saturated or unsaturated linear or branched 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; a corresponds to a maximum possible oxidation number of element X minus 4; b corresponds to an integer which obeys the condition 0≦b<(8 minus the maximum possible oxidation number of the element X); c and d are integers so that a+b+c+d= 4 and the iron oxide pigment have an oxidation stability, determined by an oxidation stability test, of ≧10° C. as compared with the uncoated iron oxide pigment.