Seven crystal systems with 14 Bravais points

P= simple, C= base centered , I= body centered, F= face centered

Atomic radius (r) –

The atomic radius is defined as the half the distance between neighboring atoms in a crystal of pure element.

Co-ordination number-defined as the no: of equidistant neighbors that an atom has the given structure .Greater the co-ordination no: the atom are said to be closely packed.

Packing factor (PF)-It is the ratio of volume occupied by the atoms or molecule in unit cell to the total volume of the unit cell

Simple crystal structure

1. Simple cubic structure (SC)

2. Body centered structure (BCC)

3. Face centered structure (FCC)

Packing factor of SC.BCC, FCC

1. Simple cubic