Formulations based on water soluble gold compounds suitable for coloring ceramic manufactured articles

Composition for colouring ceramic manufactured articles at their surface and to a depth of at least 1 mm in shades from pink to purple to violet, said composition consisting of a solution in water or in mixture of water with a water soluble organic solvent of a monovalent gold thiolate that during the ceramic firing cycle releases corrosive vapours in quantity not higher than 2gSO2/g Au deposited, comprised in the formulas Au—S—R—X and Au—S—R—H where R stands for a linear or branched bivalent radical of aliphatic or aromatic or cycloaliphatic or heterocyclic class, optionally with substituents, selected from the group consisting of aminic, amidic, hydroxylic, carboxylic, hydrocarbylico and carbonylic groups or CONH—, in the chain;

• X stands for a monovalent group selected from, the group consisting of —COOH, SO2OH, —OH, —CONH2, —NH2 and —O—P(O) (OH)2, in which H atoms may be replaced by alkyl groups and wherein acid groups may optionally be salified with amines or alkaline or alkaline earth metals and basic groups may optionally be salified with organic acids.