Practice portal › Semiconductor Electronics › Crystal Structure and Bonding

For a cubic crystal structure, which one of the following relations indicating the cell characteristics is correct?

Asked in NEET 2007 · Unit cells and lattice parameters

• (1) a e b e c and α=β=γ=90°
• (2) a=b=c and α eβ eγ=90°
• (3) a=b=c and α=β=γ=90°
• (4) a e b e c and α eβ and γ e90°

Step-by-step solution

Why the other options are wrong

• (1) comes from three unequal edges at right angles describe an orthorhombic cell, not a cubic one.
• (2) comes from equal edges with unequal angles describe a rhombohedral cell; and the condition as written is self-contradictory, since α eβ yet γ=90° leaves the cell not cubic either way.
• (4) comes from unequal edges with unequal, non-right angles describe a triclinic cell, the least symmetric of all.

Reading this solution needs no sign-in. You only sign in to practise against the clock and keep your progress.