Question

Which of the following conditions are applied to the orthorhombic crystal structure?

(a) a1=a2=a3 and α=β=\(\ddot{\gamma}\)=90

(b) a1=a2≠a3 and α=β=\(\ddot{\gamma}\)=90

(c) a1≠a2≠a3 and α=β=\(\ddot{\gamma}\)=90

(d) a1≠a2≠a3 and α=β=\(\ddot{\gamma}\)≠90

The question was asked at a job interview.

The above asked question is from Principles topic in section Corrosion Principles of Corrosion Engineering

Answer 1

The correct option is (c) a1≠a2≠a3 and α=β=\(\ddot{\gamma}\)=90

Explanation: Crystal structures are divided into 14 different types based on the structure of the unit cell and arrangement of atoms in it. These 14 different types are called Bravais lattice. And the conditions for orthorhombic crystal structure is a1≠a2≠a3 and α=β=γ̈=90

, where a1, a2, a­3 are unit vectors in three directions and α, β, γ̈ are angles between them.