# Synthesis of Copper(I) Iodide

Copper(I) iodide is usually made by the reduction of copper(II) salts. An example of using potassium iodide and copper(I) sulphate is shown below.

$$\ce{2CuSO4 + 4KI + 2Na2S2O3 -> 2CuI + 2K2SO4 + Na2S4O6 +2NaI}$$

I did another method of synthesising $\ce{CuI}$ by preparing it directly from its elements, with $\ce{NaI}$ as the solvent for solid $\ce{I2}$: $$\ce{2Cu + I2 -> 2CuI}$$

May I know why the 2nd method (direct synthesis) is better than the 1st in terms of green chemistry?