Question

why is the volume of the primitive unit cell smaller than the conventional unit cell? What are the primitive vectors of the fcc (face centered cubic)

Answer #1

The primitive unit cell is constructed in such a way that there exists only one Bravais lattice point. This results in the increase in density of the number of points thereby decreasing the volume as it is inversely proportional to the number of point density.

----------------------------------------------------------------------------------------------------------------

If a be the lattice parameter and denotes the unit cell vectors then the primitive vectors of the FCC is given by

a) A monochromatic x-ray beam gives diffraction of a 18 °C
degree cubic crystal at an angle of 2θ = 150.8 °. When the same
experiment is repeated at a temperature of 318 degrees, the
diffraction angle is 141.6 °. What is the linear expansion
coefficient of this crystal? Calculate.
b) Find the lattice vectors and the angles between the lattice
vectors of conventional and primitive unit cells for surface
centered cubic (FCC) lattice. Find the volume of the unit...

a) Generally, the crystals are expected to expand by
temperature. What are the reasons for this? In which cases, it can
be expected to decrease the size of the objects whose temperature
increases.
b) Explain the reasons for the formation of the forbidden
band.
c) Explain the source of diamagnetism (Paul Langevin 1905).
d) Find the mesh vectors and the angles between the mesh vectors of
conventional and primitive brim cells for volume centered cubic
(BCC) mesh. Find the volume...

Inorganic Chemistry: Show that the atoms occupy only 52.4% of
the total volume in a primitive or simple cubic unit cell.(By
contrast, in a closest-packed structure like fcc, the atoms occupy
74% of the total volume)

For a given primitive cell volume V, which monoatomic crystal
will have its nearest neighbours furthest away, between simple
cubic, BCC, and FCC?

Find the volume
of the primitive unit cell in a crystal of Chromium.

1. Unit Cells
i. A certain metal crystallizes in a face-centered cubic unit
cell. If the atomic radius is 150 pm, calculate the edge length
(cm) and volume of the unit cell (cm3)?
ii. If said metal is Gold (Au), calculate the density.

What is the relation between atomic radius r and lattice
constant a in the case of face- centered cubic (FCC) structure?
State the number of atoms in a unit cell for FCC structure and
hence deduce the atomic packing factor.

Gold is a face-centered cubic structure that has a unit cell
edge length of 4.08 Å. There are four gold atoms per unit cell.
How many gold atoms are there in a sphere that is 13 nm in
diameter? Recall that the volume of a sphere is
4/3πr^3.

Aluminum metal crystallizes in a face-centered cubic unit cell.
If the atomic radius of an Al is 1.43Angstroms, what is the density
of aluminum (in g/cm^3)

Calculate the density of Ca (s) in a face centered cubic unit
cell. (The atomic radius of Ca is 1.97 Å)

ADVERTISEMENT

Get Answers For Free

Most questions answered within 1 hours.

ADVERTISEMENT

asked 21 minutes ago

asked 50 minutes ago

asked 1 hour ago

asked 1 hour ago

asked 1 hour ago

asked 1 hour ago

asked 1 hour ago

asked 1 hour ago

asked 2 hours ago

asked 2 hours ago

asked 2 hours ago

asked 2 hours ago