A solid object is in the
states of mattercharacterized by resistance to deformationand changes of volume. At the microscopic scale, a solid has these properties :
atoms or molecules that compose the solid are packed closely together.
* These constituent elements have fixed
positions in spacerelative to each other. This accounts for the solid's rigidity. In mineralogy and crystallography, a crystal structure is a unique arrangement of atoms in a crystal. A crystal structure is composed of a unit cell, a set of atoms arranged in a particular way; which is periodically repeated in three dimensions on a lattice. The spacing between unit cells in various directions is called its lattice parameters. The symmetry properties of the crystal are embodied in its space group. A crystal's structure and symmetry play a role in determining many of its properties, such as cleavage, electronic band structure, and optical properties.
** If sufficient force is applied, either of these properties can be disrupted, causing permanent deformation.
* Because solids have
thermal energy, their atoms vibrate. However, this movement is very small, and cannot be observed or felt under ordinary conditions.
The branch of
physicsthat deals with solids is called solid-state physics, and is a type of condensed matter physics. Materials scienceis primarily concerned with properties of solids such as strength and phase transformations. It overlaps strongly with solid-state physics. Solid-state chemistryoverlaps both of these fields, but is especially concerned with the synthesis of novel materials.
The lightest known solids are
aerogels. The lightest aerogel produced has a density of 1.9 mg/cm³ or 1.9 kg/m³ (1/530 the density of water).Fact|date=July 2008
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