Which crystal system is the most symmetrical?

Which crystal system is the most symmetrical?

• A. Tetragonal
• B. Monoclinic
• C. Hexagonal
• D. Isometric or Cubic

Answer: (D)

Symmetry in crystals is about how many rotations or reflections leave the form unchanged. The cubic, or isometric, system has equal lengths along all three axes and right-angle intersections, which allows a large set of symmetry operations. You can rotate a cube by 90 degrees around any axis and it still looks the same; there are also 120-degree rotations about the body diagonals and many mirror planes. This abundance of symmetry operations makes a cubic crystal look identical from many directions, more than any other crystal system. Other systems have unequal axes or tilted angles, which limits the number of symmetry operations and reduces overall symmetry. So, the cubic (isometric) system is the most symmetrical.

Symmetry in crystals is about how many rotations or reflections leave the form unchanged. The cubic, or isometric, system has equal lengths along all three axes and right-angle intersections, which allows a large set of symmetry operations. You can rotate a cube by 90 degrees around any axis and it still looks the same; there are also 120-degree rotations about the body diagonals and many mirror planes. This abundance of symmetry operations makes a cubic crystal look identical from many directions, more than any other crystal system. Other systems have unequal axes or tilted angles, which limits the number of symmetry operations and reduces overall symmetry. So, the cubic (isometric) system is the most symmetrical.