Let's, Calculate the number of atoms per unit cell in the FCC lattice:
In an FCC unit cell, there are 8 corner atoms, each shared by 8 unit cells and 6 face-centered atoms, each shared by 2 unit cells.
Total number of atoms in FCC unit cell: \(8\times\frac{1}{8}+6\times\frac{1}{2}\) = 1+3 = 4
Calculate the number of tetrahedral voids per unit cell in the FCC lattice:
In an FCC unit cell, there are 8 tetrahedral voids. If only alternate tetrahedral voids are occupied, then 4 tetrahedral voids are occupied per unit cell.
Total number of occupied tetrahedral voids = 4
Calculate the total number of atoms in the modified structure:
Total atoms in FCC lattice = 4 and Total atoms in tetrahedral voids = 4
Total number of atoms per unit cell=4+4=8
The relationship between the edge length a and the atomic radius r, since tetrahedral voids forms at \(\frac{1}{4}th\) of body diagonal
\(\frac{a\sqrt{3}}{4}=2r\)
\(a=\frac{8r}{\sqrt{3}}\)
Packing efficiency (PE) is the ratio of the volume occupied by atoms to the volume of the unit cell, multiplied by 100%:
Packing efficiency = \(\frac{8\times\frac{4}{3}\pi r^3}{a^3}\times100\)
\(\frac{8\times\frac{4}{3}\pi r^3}{(\frac{8r}{\sqrt{3}})^3}\times100\simeq35\%\)
So, The correct option is (B): 35
A cubic solid is made up of two elements $X$ and $Y$ Atoms of $X$ are present on every alternate corner and one at the enter of cube $Y$ is at $\frac{1}{3} td$ of the total faces The empirical formula of the compound is
List-I | List-II | ||
(A) | Hexagonal | (I) | ∝ ≠ β ≠ γ ≠ 90° |
(B) | Orthorhombic | (II) | ∝ = γ = 90°, β ≠ 90° |
(C) | Triclinic | (III) | ∝ = β = 90°, γ = 120° |
(D) | Monoclinic | (IV) | ∝ = β = γ = 90° |
Solids are substances that are featured by a definite shape, volume, and high density. In the solid-state, the composed particles are arranged in several manners. Solid-state, in simple terms, means "no moving parts." Thus solid-state electronic devices are the ones inclusive of solid components that don’t change their position. Solid is a state of matter where the composed particles are arranged close to each other. The composed particles can be either atoms, molecules, or ions.
Based on the nature of the order that is present in the arrangement of their constituent particles solids can be divided into two types;