Silicon nanocrystals with chemically accessible surfaces are produced in solution in high yield. Silicon tetrahalide such as silicon tetrachloride (SiCl.sub.4) can be reduced in organic solvents, such as 1,2-dimethoxyethane(glyme), with soluble reducing agents, such as sodium naphthalenide, to give halide-terminated (e.g., chloride-terminated) silicon nanocrystals, which can then be easily functionalized with alkyl lithium, Grignard or other reagents to give easily processed silicon nanocrystals with an air and moisture stable surface. The synthesis can be used to prepare alkyl-terminated nanocrystals at ambient temperature and pressure in high yield. The two-step process allows a wide range of surface functionality.