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raees29
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In Material Science, what is a primitive cell when speaking crystals.
Primitive unit cell contains only one lattice point while conventional unit cell have more than one point, and as said by M Quack are usually considered for symmetry purpose.raees29 said:In Material Science, what is a primitive cell when speaking crystals.
hokhani said:Primitive unit cell contains only one lattice point while conventional unit cell have more than one point, and as said by M Quack are usually considered for symmetry purpose.
You can choose a Wigner-Seitz cell that is primitive and has the full symmetry of the lattice. I think one reason of using conventional unit cells is that it sometimes makes simpler the calculations.kaio marques said:That is how is defined in my book. Thus, the disadvantage of using a primitve cell is that how you can only have one lattice point inside of, sometimes you will get a pretty weird shaped cell. If you are more flexible, and if you decide to have more lattice points inside of your unit cell, you can get a better shape. For instance, if you use a cube with for lattice points, you can describe the Bravais lattice of a FCC very nicely. However, if you try to describe this very same lattice with a primitive cell, you will get a very weird thing.
Please, let me know if that helped you. I am also studying this subject, so we could discuss it together in more depth.
A primitive cell is the smallest repeating unit of a crystal lattice, which is the regular pattern of atoms or molecules that make up a crystal. It contains the minimum number of atoms or molecules that can be repeated to create the entire crystal structure.
A unit cell is also a repeating unit of a crystal lattice, but it may contain more than one primitive cell. The primitive cell is the simplest and most basic unit, whereas the unit cell may be composed of several primitive cells depending on the crystal structure.
A primitive cell must have three axes of equal length that intersect at 90-degree angles, as well as three axes of different lengths that also intersect at 90-degree angles. It must also have a unique set of lattice points, which are the positions where atoms or molecules can be placed to form the crystal structure.
Studying primitive cells is important in understanding the structure and properties of different materials. By understanding the arrangement of atoms or molecules in a crystal lattice, scientists can predict the physical, chemical, and mechanical properties of a material, which has implications in fields such as material science, engineering, and medicine.
Primitive cells can be determined experimentally using techniques such as X-ray crystallography, which involves bombarding a crystal with X-rays and analyzing the diffraction pattern to determine the arrangement of atoms or molecules. Other methods include electron microscopy and neutron diffraction. Computational methods, such as density functional theory, can also be used to predict the primitive cell of a material.