In triclinic crystal system, we observe all sides and angle to unequal to each or (a ? b ? c and ? ? ? ? ? ? 90^o), thus giving least symmetry (1-fold symmetry) among all 7 Bravais Lattices.

r=(?3)/4×a and APF = (volume of effective number of atoms/volume of unit cell).

A crystalline structure has very close packing of atoms thus giving rise to high density to material it possesses when compared to its non-crystalline form. For example, quartz being crystalline form of silica has a density of about 2.65 gm/cm³, whereas its ally?non-crystalline form silica glass has a density of 2.20 gm/cm³. For reference, or properties being differentiated between crystalline and non-crystalline forms are tabulated below.

In an FCC unit cell, re are eight atoms: one at each corner of cube and six face centered atoms of six planes of cube. As corner atoms are shared by eight adjacent cubes and face centered atoms by two adjacent unit cells, total effective number of atoms in an FCC unit cell will be 4.

In triclinic crystal system, we observe all sides and angle to equal to each or (a = b = c and ? = ? = ? = 90^o), thus giving highest symmetry (four 3-fold symmetry) among all 7 Bravais Lattices.

Rhombohedra have all sides equal and all angles equal but not 90^o.

For any corner atom of BCC unit cell, nearest atoms are body centred atoms. There are eight-unit cells in neighbours with body-centered atoms. Hence, coordination number for a BCC cubic unit cell is 8.

a=2?2×r and APF = (volume of effective number of atoms/volume of unit cell).

In non-crystalline structure, re is no definite packing of atoms, which makes m to possess any random shape, furr se atoms are being bonded by weak secondary bonds with Van der Wall?s forces, thus giving a low density to material.

Monoclinic have all sides unequal and two angles equal to 90^o.