Ionic crystals are crystals that formed on the basis of an ionic bond, ie its constituent particles of give and take of electrons resulting in the force of attraction between positive ions and negative ions.Examples of this crystal is NaCl and CsCl.Ionic crystals have properties, among others; hard and stable, poor conductors, high melting point, translucent, menyerapradiasi infrared, and easily soluble in polar liquids such as water.
Covalent Bond
Covalent crystals are crystals that are formed by covalent bonds, namely sharing of electrons and atoms. An example is the diamond crystal, silicon, germanium, and silicon carbide (SiC). In the diamond crystal, a carbon atom covalently linked to four other carbon atoms in a tetrahedral shape.Kristalkovalen have among other properties, very loud, very high melting point, translucent, semi-conductors, and difficult to dissolve in ordinary liquids.
Metal Bond
Metal bonded crystals are crystals that formed on the metal bond, which is the bond between the electron gas with positive ions making up the metal. In a metal, the valence electrons of each atom is easy to move from one atom to another atom so that the valence electrons become the common property of all metal atoms. These crystals have properties, among others; good conductor, opaque, shiny and can be mixed with other metal crystals..
Molekuler Bond ( van der Waals's Bond)
Crystalline molecular bond is formed is a crystal based on van der Waals bond, namely the bond between the molecules which have no permanent electric dipole. Examples of this crystal is He, Ne, Ar, CH4, and GeCl4 in solid form. Example He, Ne, Ar, CH4, and GeCl4 in solid form..
Hydrogen Bond
Hydrogen bonded crystals are crystals that form hydrogen bonds based on those. Examples of this crystal is H2O or ice crystals. In an H2O molecule, the atoms H and O atoms covalently bonded to molecules of H2O is neutral.
CRYSTAL VIBRATION
Phonons
Phonons
Phonons in quantum physics is quantum mode of vibration on the rigid crystal lattice, such as crystal lattice in solids. Crystals can be formed from solution, vapor, melt or a combination of all three.The formation is strongly influenced by the rate of crystal nucleation and growth. When growth is slow, crystals formed will be quite big, along with the arrangement of atoms or molecules with repeated regularly so that the minimum potential energy. Solid-state physics are intimately associated with the crystal and the electrons in it.
Crystal Vibrations monatomic
There are two modes of vibration of atoms in a crystal:Longitudinal vibration is the vibration mode of the vibration in the direction of propagation.Transverse vibration is a vibration mode vibration direction perpendicular to propagation direction
There are two modes of vibration of atoms in a crystal:Longitudinal vibration is the vibration mode of the vibration in the direction of propagation.Transverse vibration is a vibration mode vibration direction perpendicular to propagation direction
A monatomic simple cubic crystal [100], [110], and [111] which have vibrating frequency elastic waves, in terms of vector wave will propagate in parallel and perpendicular to the direction of wave vector.Each displacement field (S) from its equilibrium position will have vekktor wave with three shape modes: one longitudinal polarization and two transverse polarization.
There are two types of phonons in the crystal lattice:optical and acoustic
Crystal Vibrations diatomic
The spread of phonons to crystal simple diatomic or more will give a different direction than the spread of monatomic crystals. Each polarization will provide direction for distributing connection ω on k with the pattern of two branches: the acoustic and optical. So that would be obtained by LA and TA (transverse acoustic and longitudinal acoustic), and the LO and TO (longitudinal optical and optical tranversal). Simple cell with the P atom has a branch with 3 branches 3P 3P-3 acoustic optical branches, number of branches hereinafter referred to as degrees of freedom. For diatomic cubic crystal with the M1 and M2 are different. The equation of motion by assuming each field interacts only with the nearest neighbor atoms and the same force constant, is obtained:
The spread of phonons to crystal simple diatomic or more will give a different direction than the spread of monatomic crystals. Each polarization will provide direction for distributing connection ω on k with the pattern of two branches: the acoustic and optical. So that would be obtained by LA and TA (transverse acoustic and longitudinal acoustic), and the LO and TO (longitudinal optical and optical tranversal). Simple cell with the P atom has a branch with 3 branches 3P 3P-3 acoustic optical branches, number of branches hereinafter referred to as degrees of freedom. For diatomic cubic crystal with the M1 and M2 are different. The equation of motion by assuming each field interacts only with the nearest neighbor atoms and the same force constant, is obtained:
M1 . d2Us/dt2 = C(sup>Vs< + Vs-1 - 2Us
M2 . d2Vs/dt2 = C(Us+1 + Us - 2Vs
The equation above can be completed in the current waveform amplitude scale both U and V:
Us = 
dan Vs = 
dan Vs = So with mengsubtitusikan equation above:
-ω2M1.U= CV[1 + 
-2 CU
-2 CU-ω2M2.V= CU[1 + 
-2 CV
-2 CV