Bravais Lattices
Fourteen distinct three-dimensional lattice types.
Practise States of Matter & Solutions All States of Matter & Solutions topics
Fourteen distinct three-dimensional lattice types.
Practise States of Matter & Solutions All States of Matter & Solutions topics
A Bravais lattice is one of the fourteen distinct three-dimensional arrangements of lattice points, each describing a unique translational symmetry. The fourteen lattice types arise by combining the seven crystal systems with the centring options of primitive, body-centred, face-centred and base-centred. Every point in a Bravais lattice has an identical environment, so every crystal structure is built on one of these lattices. Knowing which lattice applies is the first step in determining a crystal structure from diffraction data. The fact that only fourteen lattice types exist shows that the number of possible lattice arrangements is limited.
Key ideas: Count: cubic 3, tetragonal 2, orthorhombic 4, monoclinic 2, triclinic 1, hexagonal 1, rhombohedral 1, total 14. Centering types P, I, F, C. Some combinations are redundant, for instance base-centred tetragonal is equivalent to primitive tetragonal with a smaller cell. Lattice points are mathematical, not necessarily atoms.
Common mistakes and connections: Students think each lattice point is one atom, but a point may represent a group of atoms called the basis. Another mistake is thinking diamond is a Bravais lattice; it is fcc with a two-atom basis. Also, hcp is not a Bravais lattice by itself. Links to crystal systems, unit cell and structures of real solids.
The seven crystal systems contain 14 Bravais lattices in total (P, I, F and C variants): cubic 3, tetragonal 2, orthorhombic 4, monoclinic 2 and others 1. The interactive lesson shows this as a live animation or chart.
The cubic system has three Bravais lattices: primitive cubic, body-centred cubic and face-centred cubic.
Fourteen distinct three-dimensional lattice types.
Bravais Lattices is a advanced topic in States of Matter & Solutions. It builds on beginner and intermediate topics, so review those first if needed.
Study these earlier topics in States of Matter & Solutions first: Packing Efficiency, Tetrahedral and Octahedral Voids, Crystal Systems.
The next topics in States of Matter & Solutions are X-ray Diffraction and Bragg's Law and Crystal Defects.
Yes. The interactive lesson includes a self-check question on Bravais Lattices, and the States of Matter & Solutions quiz draws on every topic in this area.
Bravais Lattices is topic 65 of 109 in States of Matter & Solutions.