Which substance has vibrating particles in regular fixed position?

Answer 1

Brief Answer: A crystal is a regular arrangement of atoms or molecules but a solid may have a regular arrangement or a more random positioning of its constituents. All crystals are solids but not all solids are crystals. One normally makes the distinction clear with the terms crystalline solid and noncrystalline solid.

All solids are a collection of atoms and molecules, but not all solids have these atoms and molecules in a regular arrangement. When such regularity is present, it is properly called a crystal.

In solids the particles are in a fixed position, though vibration is present as a result of thermal motion. In a liquid or gas, particles move as a consequence of the thermal motion. In a solid, the forces between particles are strong enough to hold them in place.

The obvious examples of crystals one normally has experience with include simple table salt, diamonds and ice. (These normally have a highly regular atomic arrangement, but of course there is some distinction between an ideal perfect crystal and one with impurities and cracks. Nonetheless, at the atomic level, the crystalline arrangement is highly regular.)

The obvious examples of noncrystalline solids includes such things as glass, wood, bone and plastic. Actually, most everyday solids are noncrystalline. It is often true that apparently amorphous things like rock actually contain some microscopic crystals so one can not say always from outer appearances that something has no crystals at all inside.

Like most broad classifications, there are exceptions and special cases. Quasicrystals and liquid crystals are two examples of materials which have unusual structures and are the subject of scientific study.

Answer 2

All known substances in the universe when they are above Absolute Zero. However, no known substance has ever reached absolute zero and been recorded.