Answer to Question #98756 in Physical Chemistry for Abhishek

Question

Mention the names of crystal system which has

(i) four bravais lattices , and
(ii) unequal sides and unequal angles and no angle equal to 90° .

Answer 1

i Orthorhombic crystal system (4 lattices)

Thesimple orthorhombic is made by deforming the square bases of the tetragonal into rectangles, producing an object with mutually perpendicular sides of three unequal lengths. The base orthorhombic is obtained by adding a lattice point on two opposite sides of one object's face. The body-centered orthorhombic is obtained by adding one lattice point in the center of the object. And the face-centered orthorhombicis obtrained by adding one lattice point in the center of each of the object's faces.

Hemimorphite is the most common mineral with this symmetry.

ii Triclinic crystal system

In the triclinic system, the crystal is described by vectors of unequal length, as in the orthorhombic system. In addition, the angles between these vectors must all be different and may not include 90°.

Examples: Tantite (oxide mineral), Wollastonite (Inosilicate mineral)