Perfluorodecanethiol stabilized silver (Ag) nanocrystals were synthesized in supercritical (sc)-CO2 through arrested precipitation, by reducing silver acetylacetonate (Ag(acac)) with hydrogen in the presence of fluorinated thiol, The CO2 density used during synthesis controls the particle size and polydispersity. At high solvent densities the ligands provide a strong steric barrier that maintains small particles with similar to20 Angstrom diameter. At lower solvent densities the repulsions between capping ligands are weak, resulting in larger similar to40 Angstrom diameter nanocrystals with higher polydispersity. Conditions effective for steric stabilization, such as long ligands and high solvent density, quench nanocrystal growth at relatively low ligand binding densities, which leads to smaller nanocrystals. Under poor solvent conditions, particles grow to larger sizes before the coverage of capping ligand is sufficient to prevent coagulation of metal particles.