Crystal structures: identify elements with HCP (hexagonal close-packed) lattice Select the correct set for HCP among the given choices. Choose the correct option.
Mechanical Engineering
Engineering Materials
Difficulty: Medium
Choose an option
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AZinc, magnesium, cobalt, cadmium, antimony, bismuth
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BGamma-iron, aluminium, copper, lead, silver, nickel
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CAlpha-iron, tungsten, chromium, molybdenum
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DNone of the above
Answer
Correct Answer: None of the above
Explanation
ConceptTypical HCP metals: Zn, Mg, Cd, Co, Ti, Zr, etc. However, antimony (Sb) and bismuth (Bi) are rhombohedral, not HCP. The other sets list FCC (option b) and BCC (option c) metals.
Option check• (a) includes HCP members (Zn, Mg, Cd, Co) but incorrectly adds Sb and Bi → set is not purely HCP.• (b) FCC set (γ-Fe, Al, Cu, Pb, Ag, Ni).• (c) BCC set (α-Fe, W, Cr, Mo).Thus, the only correct choice is “None of the above.”
Final AnswerNone of the above