Why is salt a crystal?

Question

Why is salt a crystal?

Answer 1

When it is dry, salt forms a crystal because that gives it an energy advantage.  In general, if something melts because you heat it, it will form a crystal if you cool it.  That's why ICE is a crystal.  When you cool it, it crystallizes to give up energy, called the "heat of crystallization."  For ice, that is on the order of 80 calories per gram per degree or something close to that.

Answer 2

"Sodium chloride forms crystals with cubic symmetry. In these, the larger chloride ions, shown to the right as green spheres, are arranged in a cubic close-packing, while the smaller sodium ions, shown to the right as silver spheres, fill the octahedral gaps between them.

Each ion is surrounded by six ions of the other kind. This same basic structure is found in many other minerals, and is known as the halite structure. This arrangement is known as cubic close packed (ccp). It can be represented as two interpenetrating face-centered cubic (fcc) lattices, or one fcc lattice with a two atom basis. It is most commonly known as the rocksalt crystal structure.

It is held together with an ionic bond and electrostatic forces."

—The crystal structure of sodium chloride: http://en.wikipedia.org/wiki/Sodium_chlo...

See also:

Ionic bond: http://en.wikipedia.org/wiki/Ionic_bond

Cubic crystal system: http://en.wikipedia.org/wiki/Cubic_cryst...

Answer 3

Salt is made up of sodium and chlorine and the way they bond together makes a crystal lattice structure, that looks like a cube. NaCl sodium chloride. One sodium for every chloride. Think of two different colored tennis balls stacked into a cube shape. :)