The formation of mixed monolayers of hydridospherosilsesquioxane clusters (H8Si8O12) and alkylsilanes (H2n+1Cn-SiH3) on Au has been investigated using X-ray photoelectron and reflection-absorption infrared spectroscopies and scanning tunneling microscopy. All of the techniques indicate the displacement of the majority of the siloxane clusters from the surface in favor of the alkylsilane.