# How many types of 3D packing are possible?

In my book it's said that there are 3 types of unit cubic cell - primitive , face and body centered . But for 3d packing types they have only mentioned FCC and HCP . I know that these 2 concepts- unit cell and packing types are different but it's the packing that determines the type of unit cell , right ? So are there any packing types like primitive packing and body centered packing ? .

• FCC and HCP are the two types that give 3d close packing i.e. packing atoms as densely as possible. There are many more types of unit cell, it's just that they don't achieve close packing. FCC has face-centred cubic unit cell and HCP has hexagonal unit cell. – Shoubhik R Maiti Mar 27 at 10:49
• chemistry.stackexchange.com/questions/35273/… May prove useful. – Jon Custer Mar 27 at 15:17
• Are there any packing types like primitive packing and body centred packing ? – Debodit Ray Mar 28 at 13:59