Abstract: An improved process for the preparation of bismuth vanadate pigments and solid solutions based on bismuth vanadate by a) mixing a solution of a bismuth (III) salt containing, if required, one or more further metal salts or a mixture thereof with the aqueous solution of a vanadate salt containing, if required, a molybdate, tungstate or sulfate salt or a mixture thereof and b) subjecting the suspension thus obtained to a subsequent aftertreatment to convert the particles first precipitated in amorphous form into crystalline compounds, wherein during the mixing and/or during the subsequent aftertreatment step fluoride ions are used.

Abstract: A process for the preparation of lead molybdate pigments containing lead chromate, lead sulfate and lead molybdate, which comprises preparing the lead molybdate pigments by reacting an aqueous solution of a lead salt with an aqueous solution containing chromate, molybdate and sulfate salts or with an aqueous solution of each of said salts using 2 to 5 mol % of lead molybdate seed crystals, based on the total molar amount of lead chromate, lead sulfate and lead molybdate. The lead molybdate pigments so obtained are strong and are highly suitable for coloring organic materials of high molecular weight.

Abstract: The invention relates to orthorhombic lead chromate pigments of greenish hue, which contain lead chromate and lead sulfate in the weight ratio of 60:40 to 100:0, and which are characterized by a tinctorial strength of 0.067 to 0.103 at a standard depth of shade of 1/25 in accordance with DIN 53 235 and by an opacity factor Y.sub.black /Y.sub.white of 0.78 to 0.87. These pigments are obtainable by mixing an aqueous solution of a chromate and, if necessary, of a sulfate, under high turbulence.