absolutely any chemical substance that exists in nature, formed by a large number of identical particles, which are interconnected.All matter exists in three states of aggregation: gaseous, liquid and solid.When complicated thermal motion (at low temperatures) and of the solids particles strongly oriented in space, which is manifested in their exact structural organization.
crystal lattice of substances - a structure with a geometrically ordered arrangement of particles (atoms, molecules or ions) in certain points of space.The various gratings are distinguished inter-node space directly nodes - the point at which the particles themselves are located.
crystal lattice is of four types: metal, molecular, atomic, ionic.Types of arrays are determined according to the kind of particles located in their nodes, and the character of the bonds between them.
crystal lattice called molecular in if nodes are located in its molecule.They are linked by intermolecular relatively weak forces called van der Waals, but the atoms themselves within the molecule are connected substantially stronger covalent bonds (polar or non-polar).Molecular crystal lattice characteristic of chlorine, solid hydrogen, carbon dioxide and other substances that are gaseous at normal temperature.
crystals which form the noble gases, also have molecular lattice consisting of monohydric molecules.Most organic solids have such a structure exactly.The number of inorganic substances, characteristic molecular structure, is very small.This, for example, solid halogenated, natural sulfur, ice, solid simple substances and others.
When heated relatively weak intermolecular bonds are broken fairly easily, so a substance with such bars have very low melting point and low hardness, they are insoluble or poorly soluble in water, solutions are virtually non-conductive, characterized by considerable volatility.And a minimum boiling point - from substances of nonpolar molecules.
Metal crystal lattice is called such, components of which are formed by atoms and positive ions (cations) with a metal-free valence electrons (unhook of the atoms in the formation of ions), moving randomly in the crystal.However, these electrons are essentially semi-free, because they can move freely only within that limit, this crystal lattice.
Electrostatic electrons and positive ions of metals are mutually attracted, which explains the stability of the metal lattice.The collection of free moving electrons called electron gas - it provides good electrical and thermal conductivity of metals.When an electric voltage electrons rush to the positive particles, participating in the creation of electric current and interacting with ions.
Metal crystal lattice is characterized mainly for basic metals as well as compounds of different metals with each other.The main properties that are inherent in metallic crystals (mechanical strength, volatility, melting point), strongly enough fluctuate.However, the physical properties such as ductility, malleability, high electrical and thermal conductivity, the characteristic metallic luster peculiar only exclusively crystals with metal bars.
