Topic summary
Monoclinic crystal system
In crystallography, the monoclinic crystal system is one of the seven crystal systems. A crystal system is described by three vectors. In the monoclinic system, the crystal is described by vectors of unequal lengths, as in the orthorhombic system. They form a parallelogramprism. Hence two pairs of vectors are perpendicular (meet at right angles), while the third pair makes an angle other than 90°.