(3Q) Solids Flashcards
Atoms or molecules have no long range order. Glass, rubber, many
plastics
Amorphous solids
Atoms or molecules are arranged in a well-ordered three dimensional array
Crystalline Solids
are composed of huge number of small crystals with definite geometric shape that makes them RIGID and INCOMPRESSIBLE.
Crystalline Solids
Why are Crystalline Solids considered true solids?
sharp melting point and definite heat of fusion
basic repeating structural unit of crystalline solids
unit cell
atoms or molecules are represented by each sphere and are identically arranged are called?
lattice point
This unit cell has EQUAL edge lengths and angles, and the atoms are located at the corners of the cube and at the center of each face.
Cubic
3 types of cubic unit cells
simple cubic, body-centered cubic, and face-centered cubic.
This unit cell has TWO different edge lengths and EQUAL angles, with the atoms located at the corners of the parallelepiped.
Tetragonal
This unit cell has THREE different edge lengths and EQUAL angles, with the atoms located at the corners of the parallelepiped.
Orthorhombic
This unit cell has THREE different edge lengths and TWO different angles, with the atoms located at the corners of the parallelepiped
Monoclinic
This unit cell has THREE different edge lengths and THREE different angles, with the atoms located at the corners of the parallelepiped
Triclinic
This unit cell has EQUAL edge lengths and angles, but the parallelogram faces are not perpendicular to each other.
Rhombohedral
This unit cell has EQUAL edge lengths and angles, but the atoms are located at the corners of a hexagon, and the top and bottom faces are hexagons as well
Hexagonal
- Held together by weak IMFs
- Fairly low melting points
Molecular Solids