Aqueous electroless plating solutions

It has now been found that one or more metals selected from the group consisting of tin, lead, bismuth, indium, gallium and germanium may be deposited onto a metal surface utilizing an aqueous electroless plating solution which comprises (A) at least one solution-soluble metal salt selected from the group consisting of a stannous salt, a lead salt, a bismuth salt, an indium salt, a gallium salt and a germanium salt; (B) at least one acid selected from the group consisting of fluoboric acid, alkane sulfonic acids, alkanol sulfonic acids, and mixtures thereof; (C) a complexing agent which is an imidazole-2-thione compound of the Formula III (III) wherein A and B are the same or different -RY groups wherein R is a linear, branched or cyclic hydrocarbylene group containing up to 12 carbon atoms, and Y is a hydrogen, halogen, cyano, vinyl, phenyl, or ether moiety; and (D) water. Optionally, the aqueous plating solutions may contain one or more surfactants.