Types of crystal lattices of various substances

In nature there are two types of solid bodies thatdiffer significantly in their properties. These are amorphous and crystalline bodies. And the amorphous bodies do not have an exact melting point, they gradually soften during heating, and then go into a fluid state. An example of such substances is a resin or conventional clay. But the situation is completely different with crystalline substances. They remain in a solid state to a certain temperature, and only after reaching it, these substances melt.

Here the whole thing is in the structure of such substances. In crystalline bodies, the particles from which they are composed are located at certain points. And if you connect them with straight lines, you get an imaginary frame, which is called - the crystal lattice. And the types of crystal lattices can be very different. And according to the kind of particles from which they are "built", the gratings are divided into four types. It is an ionic, atomic, molecular and metal lattice.

And at the sites of ionic crystal lattices,accordingly, ions are located, and there is an ionic bond between them. These ions can be either simple (Cl-, Na +) or complex (OH-, SO2-). And such types of crystal lattices can contain some hydroxides and metal oxides, salts and other similar substances. Take, for example, normal sodium chloride. It alternates negative ions of chlorine and positive ions of sodium, which form a cubic crystal lattice. The ionic bonds in such a lattice are very stable and the substances "constructed" by this principle have rather high strength and hardness.

There are also types of crystal lattices,called atomic. Here at the nodes there are atoms, between which there is a strong covalent bond. Atomic lattice have not so many substances. These include diamond, as well as crystalline germanium, silicon and boron. There are still some complex substances that contain silicon oxide and have, respectively, an atomic crystal lattice. It is sand, quartz, rock crystal and silica. And in most cases such substances are very strong, solid and refractory. They are also practically insoluble.

And molecular types of crystal lattices havethe most diverse substances. These include frozen water, that is, ordinary ice, "dry ice" - solidified carbon monoxide, as well as solid hydrogen sulphide and hydrogen chloride. Yet molecular lattices have many solid organic compounds. These include sugar, glucose, naphthalene and other similar substances. And the molecules that are in the nodes of such a lattice are connected with each other by polar and nonpolar chemical bonds. And despite the fact that inside the molecules between the atoms there are strong covalent bonds, these molecules themselves are kept in the lattice due to very weak intermolecular bonds. Therefore, such substances are sufficiently volatile, easily melt and do not have a great hardness.

Well and metals have the most different kindscrystal lattices. And in their nodes can be both atoms and ions. At the same time, atoms can easily be converted into ions, giving their electrons to "common use". In the same way, ions, "capturing" a free electron, can become atoms. And such a structure of the metal crystal lattice determines such properties of metals as plasticity, ductility, heat and electrical conductivity.

Also types of crystal lattices of metals, andother substances, are divided into seven basic systems in the form of elementary lattice cells. The simplest is a cubic cell. There are also rhombic, tetragonal, hexagonal, rhombohedral, monoclinic and triclinic unit cells, which determine the shape of the entire crystal lattice. But in most cases, crystal lattices are more complex than those listed above. This is due to the fact that elementary particles can be located not only in the lattice sites themselves, but also at its center or on its faces. And among metals the most common are three complex crystal lattices: face-centered cubic, body-centered cubic and hexagonal close-packed. Even the physical characteristics of metals depend not only on the shape of their crystal lattice, but also on the interatomic distance and on other parameters.