Crystal Form Flashcards
How many crystal systems are there, and what are they?
There are seven crystal systems, which are:
- Cubic (Isometric)
- Tetragonal
- Orthorhombic
- Hexagonal
- Trigonal (Rhombohedral)
- Monoclinic
- Triclinic
all three axes are of equal length and intersect at right angles (90 degrees)
cubic (isometric) crystal system
How many crystal classes are there?
32
has four axes, three of which are of equal length and lie in a plane, forming 120-degree angles, while the fourth axis is perpendicular to this plane
hexagonal system
has three axes of equal length, but they intersect at angles that are not necessarily 90 degrees, creating a rhombohedral shape
trigonal
two axes are of unequal length and intersect at an oblique angle, while the third axis is perpendicular to the other two
Monoclinic
A form in a particular crystal class that contains faces that intersect all crystallographic axes at different lengths. It has the form symbol {hkl}.
General Form
General form: {111}
Monoclinic, Triclinic, Orthorhombic
General form: {121}
Tetragonal
General form: {123}
Isometric
a set of crystal faces that completely enclose space
Close
one or more crystal faces that do not completely enclose space
Open
Found in the cubic (isometric) crystal system.
Isotropic
Found in all other crystal systems (e.g., tetragonal, orthorhombic, hexagonal, monoclinic, triclinic).
Anisotropic
