Dear Dr. Arash Motevalian 

Have a nice day

Already, You can calculate the density theoretically using a simple equation. But you must know the the ratio of the presence of each element and the density of each element participate in your composition.

Good luck

Prof. Hassanien

Do you mean that theoretical density has linear equation with mole fraction of each element?

Dear Dr. Arash Motevalian 

Absolutely, Yes the theoretical value of the density has a linear equation with mole fraction (or atomic weight percent) of each participated element in the compound. The equation is given as follows:

The volumetric mass density (ρ) = ∑(Pi/ρi )(-1)

Where p is the element percentage, ρ is the density of the element.

Good luck