The preparation, properties, and oxidation of potassium methyl to hexyl mono-thiocarbonates and of dipotassium butyl bis(monothiocarbonate) are reported. The oxidation product of the latter is a dimer. Some nickel, lead, copper, and silver complexes were isolated. The ability of monothiocarbonates to form metal complexes lies between alkyl carbonates and dithiocarbonates. Copper(I) ethyl monothiocarbonate is a tetramer.