What is the relationship between crystal symmetry (point group) and lattice symm

Question

What is the relationship between crystal symmetry (point group) and lattice symmetry? What is the fundamental difference between point group operators and space group operators? Why do we need space group operators to describe the symmetry of crystal structures? What is the relationship between crystal form and crystal structure? How do they both relate to crystal habit? If you examine a crystal and see lots of symmetry, what can you infer about the crystal's atomic structure? On the other hand, if you examine a crystal and see no symmetry, what can you infer about the crystal's atomic structure?

Explanation / Answer

1.Crystal symmetry and lattice symmetry - every crystal consists of certain atom or groups of atoms arranged in 3D pattern which is reported throughout the crystal and smallest complete unit of atom is called unit cell whereas lattice is arrangements of atoms in crystal.Crystal faces develop along planes defined by the points in the lattice.

2.Point group and space group - In point group we can do symmetry operations in two dimension or three dimensions,combining proper and improper rotation gives the point groups (crystal classes)

32 posible combination in 3 D and 32 crystal classes 7 crystal system

But in SPACE GROUPS- its include the translation operations gives the space groups.

17 two dimensional space groups

230 three dimensional space groups

3.Crystal structure is a description of the ordered arrangement of atoms, ions or molecules in a crystalline material.

Forms- is group of crystal faces all of which have the same rotation to the element of symmetry

Related Questions

Navigate

• Browse (All)
• Browse W
• Subjects

---

---

Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.