Solids


 * Solid state chemistry** is the study of the solid phase of matter.

There are two basic types of solids: crystalline and amorphous.

A crystalline solid has a uniform, organized structure, with particles aligned in what is called a crystal lattice:



An amorphous solid has no patterned or organized structure at the molecular level:



Crystalline solids are further classified into four basic types:


 * __atomic:__ These are solids composed of singular atoms at lattice points. All metals and substitutional alloys are considered atomic solids, and sometimes these solids are generally called metallic solids. Other elements that form this type of solid are the noble gases (when cooled to extremely low temperatures).




 * __molecular:__ These solids are composed of individual covalent molecules at the lattice points. Water ice, dry ice (frozen carbon dioxide), and solidified oxygen gas are all examples of molecular solids.




 * __ionic:__ The lattice points of an ionic solid are occupied by metallic ions and nonmetallic or polyatomic ions. Table salt (sodium chloride), whose crystals are cube-shaped, is an ionic solid (see above).




 * __network atomic:__ As the name implies, lattice points are occupied by atoms, which are networked - connected by covalent bonds. Sometimes these are referred to as covalent solids. Examples include most forms of carbon: diamond, graphite, fullerite; and the silicates (Si-O) such as quartz or mica.