[kino]

I'm doing gold reduction by using sodium borohydrate as the reducing agent.

Under room temperature, the 20ml 1.0mM HAuCl4 is placed on the stir plate, 0.5ml of 1% NaBH4 is added into it.

It showed a little dark violet for 1 second, then the solution turns into clear light yellow color in the end.

Is this correct, or it should be like the citrate reduction, in dark ruby red color?

Please help.

[DevaDevil]

gold (I) chloride is yellow, so you most likely have a partial reduction

only gold nanoparticles in solution are red; it gets more yellow for particles larger than ~100 nm