Patent ID: 7022469

Claim:
A method for preparing a gold sulfide colloid comprising reacting a solution of an Au(I) complex represented by formula (2) with a solution containing a sulfur compound in a protective colloid solution: [L 1 -Au(I)-(L 2 ) m]X n (2) wherein L 1 represents a compound represented by formula (1), L 2 represents a compound represented by formula (1) or a halogen atom, provided that L 1 and L 2 may be the same or different or may be combined, X represents a counter salt necessary for neutralizing the electric charge of the compound, m represents 0 or 1, and n represents a value of 0 to 1 and may be a decimal; R 1 —Ch—R 2 (1) wherein R 1 and R 2 each independently represents an alkyl group, an alkenyl group, an alkynyl group, an aryl group or a heterocyclic group, R 1 and R 2 may combine with each other to form a 3-, 4-, 5-, 6- or 7-membered ring, and Ch represents a sulfur atom, a selenium atom or a tellurium atom.