We Value Your Privacy

We and our partners use technology such as cookies on our site to personalise content and ads, provide social media features, and analyse our traffic. Click below to consent to the use of this technology across the web. You can change your mind and change your consent choices at anytime by returning to this site.

Update Consent
Loading ...

How to calculate the packing fraction of diamond lattice

Updated May 25, 2017

Atoms within solids are arranged in one of several periodic structures known as a lattice. There are seven lattice systems in total. Examples of these include the face-centred cubic, body centred cubic and simple cubic arrangements. The proportion of volume that the atoms take up with in a given lattice is known as the packing fraction. You can calculate the packing fraction of a material such as diamond with some material parameters and simple mathematics.

Loading ...
  1. Write down the equation for packing fraction. The equation is:

  2. Packing fraction = Natoms x Vatom / Vunitcell

  3. Where Natoms is the number of atoms in a unit cell, Vatom is the volume of the atom, and Vunitcell is the volume of a unit cell.

  4. Substitute the number of atoms per unit cell into the equation. Diamond has eight atoms per unit cell so the formula now becomes:

  5. Packing fraction = 8 x Vatom / Vunitcell

  6. Substitute the volume of the atom into the equation. Assuming atoms are spherical, the volume is:

  7. V = 4/3 x pi x r^3

  8. The equation for packing fraction now becomes:

  9. Packing fraction = 8 x 4/3 x pi x r^3 / Vunitcell

  10. Substitute the value for the unit cell volume. Since the unit cell is cubic, the volume is

  11. Vunitcell = a^3

  12. The formula for packing fraction then becomes:

  13. Packing fraction = 8 x 4/3 x pi x r^3 / a^3

  14. The radius of an atom r is equal to sqrt(3) x a / 8

  15. The equation is then simplified to : sqrt(3) x pi / 16 = 0.3401

Loading ...

Things You'll Need

  • paper

About the Author

Samuel Markings has been writing for scientific publications for more than 10 years, and has published articles in journals such as "Nature." He is an expert in solid-state physics, and during the day is a researcher at a Russell Group U.K. university.

Loading ...