Procedure

This experiment is about finding the primitive cells or non primitive unit cells for a given lattice. In theory, a lattice is infinite, but here we have a finite lattice for the experiment.

The experiment contains 5 lattices which are :

• Square Planar
• Simple Cubic
• Face Centered Cubic
• Body Centered Cubic
• Hexagonal Packing

The first lattice is a planar lattice, meaning it extends in only two dimensions. The remaining lattices extend in three dimensions and are a mixture of primitive and non-primitive unit cell lattices.

Finding primitive Cells

For simple lattices, primitive cells can be easily identified. In these cases, atoms form distinct shapes or polyhedra, which can be selected as part of the unit cell. The key is to find atoms that share a common reference atom, displaying different surroundings that together form the unit cell.

Steps for the Experiment

• The interface will display a canvas showing the finite lattices.
• Use the dropdown menu to select a lattice.
• Toggle the "Select Atoms" button to begin selecting atoms for the unit cell.
• Use the left-click to select an atom and right-click to de-select it.
• Once the atoms constituting the primitive or non-primitive unit cell are selected, click the Check button to evaluate your selection.
• Repeat this process for each of the five lattices.
• Additionally, there is an option to select the 3D region covered by the selected atoms, which can be toggled as needed.

Note

Some lattices have been showed with an atom radius that is smaller than the mathematically proven one to help with the visibility of the lattice points to the user.