How do you calculate theoretical density of compound?

p = n x Mr / Vc x NA

where n is the atoms/unit cell e.g. fcc packing n = 4 and for bcc packing n = 2

Mr is the Atomic Mass in g/mol

Vc is the volume/unit cell cm3 = a3 where a can be found by the radius of the atom and the packing used. e.g in bcc packing it is "a = 4r/1.732" . In Fcc packing it is "a= sin (4r)" or "a = cos (4r)"

NA is avorgados constant, = 6.023 x1023