crystal lattice
In a crystal, all particles—atoms, molecules, or ions—are arranged like rows of oranges on a fruit stand. Each orange sits exactly in its place, and this repeats layer after layer. Thanks to this strict order, crystals form smooth faces and sharp angles, like salt cubes or hexagonal snowflakes.
History
The idea that crystals have a regular internal structure was already suggested by Robert Hooke in the 17th century while examining them under a microscope. The decisive moment came in 1912 when Max von Laue predicted and obtained X-ray diffraction from crystals, and William and Lawrence Bragg derived a simple equation for deciphering the lattice, for which they received the Nobel Prize in 1915.
How it works
When water evaporates from a salty solution, sodium and chloride ions stop floating separately and line up in a strict checkerboard order, but in volume. Each sodium ion is surrounded by six chloride ions, and vice versa—this way the electric forces balance each other, and we get the familiar salt cube.
💡 Snowflakes grow from tiny ice crystals, and their hexagonal symmetry is embedded in how water molecules connect in the lattice. Although all snowflakes share common features, each is unique due to different growth conditions.