Question

The axial relationship of a rhombohedral crystal system is given as ___________

(a) a = b = c

(b) a = b ≠ c

(c) a ≠ b = c

(d) a ≠ b ≠ c

This question was posed to me in homework.

This key question is from Types of Solids, Crystal Structures and Lattices topic in portion Solid Solutions & Crystallography of Engineering Material & Metallurgy

Answer 1

Right choice is (a) a = b = c

The explanation is: The crystal system is a format by which crystal structures are classified.  Each crystal system is defined by the relationship between edge lengths a, b, and c. For cubic and rhombohedral systems, the axial relationship is given by a = b = c.