hexagonal crystal system

The Seven Crystal System - Crystals along with suitable examples are listed in the table. System Axial distances Axial angles Examples Cubic a = b = c α = β = γ = 90° NaCl,KCl, Diamond, Cu, Ag Tetragonal a = b ≠ c α = β = &g..

Calculation of Number of Particles per Unit Cell of a Cubic Crystal System - Calculation of Number of Particles per Unit Cell of a Cubic Crystal System. Keeping the following points in mind we can calculate the number of atoms in a unit cell. An atom at the c..

Another type of microphone, widely used in public-address systems, depends for its action on the piezoelectric effect possessed by certain crystals, for example Rochelle salt. The term piezoelectric effect refers to the fact that when pressure is applied on the crystal..

Keeping the following points in mind we can calculate the number of atoms in a unit cell. * An atom at the corner is shared by eight unit cells. Hence an atom at the corner contributes 1/8 to the unit cell * An atom at the face is a shared by two unit cells Contribution of each atom..

Any system where there is a constant exchange of matter and energy from the surrounding environment is called as open system. All living organisms represent open systems. Any state of a system where the rate of input of energy and matter is equal to the ra..

A characteristic property of the elements of groups 14 is that these show allotropy. Allotropy is the existence of an element in two or more forms, which are significantly different in physical properties but have similar chemical properties. The difference may be due to difference in crystal..

In addition to the particles at the corner of the cube, there is one present at the body centre position of the unit cell. Another type of unit cell, called end centered unit cell, is possible for orthorhombic and monoclinic crystal types. In an end centered unit cell, there are lattice ..

After taking into account account the above observed facts, Kekule (1865) suggested a ring structure for benzene. According to him, six carbon atoms occupied six corners of a regular hexagon in benzene and each carbon carried one hydrogen atom. To satisfy the tetravalency of carbon, the ..

The smallest three-dimensional portion of a complete space lattice, which when repeated over and again in different directions produces the complete space lattice. The size and shape of a unit cell is determined by the lengths of the edges of the unit cell (a, b and c) and by the angles a , b a..

. It is the hardest natural substance known. It has high relative density (about 3.5). It is transparent and has high refractive index (2.45). It is non-conductor of heat and electricity. It burns in air at 900C to give CO 2 . It occurs as octahedral crystals. It is insoluble in all solve..