In severe cases of poison ivy, poison oak, or poison sumac, it is a good idea to see a doctor. Sometimes large blisters need to be drained and sometimes an oral steroid such as prednisone may be useful. Systemic steroids produce rapid resolution of both the itching and the rash.
Crystalline solids have a highly ordered arrangement of constituent atoms, ions or molecules in a three-dimensional layer or lattice giving rise to distinct geometrical shapes. Thee are two important types of crystalline solids. 1  Ionic solids (represented by sodium chloride).
Solids can be divided into three categories on the basis of how the particles that form the solid pack. 1  Crystalline solids are three-dimensional analogs of a brick wall. They have a regular structure, in which the particles pack in a repeating pattern from one edge of the solid to the other.