Question

Which of the following is NOT a physical or chemical characteristic of interstitial compounds?

• A. They have high melting points, higher than those of pure metals.
• B. They are very soft and ionic in nature.
• C. They retain metallic conductivity.
• D. They are chemically inert and usually non-stoichiometric.

Answer 1

The Correct Option is B

Step 1: Understanding the Question:
The question asks to identify the incorrect property of interstitial compounds formed by transition metals.
Step 2: Detailed Explanation:
Interstitial compounds are formed when small atoms like H, C, or N are trapped inside the crystal lattices of transition metals.
- They have very high melting points, typically higher than the parent metals. Statement (A) is correct.
- They are usually extremely hard (some approach diamond in hardness). They are not ionic; the bonding is typically metallic or covalent in nature. Statement (B) is incorrect.
- The inclusion of small atoms does not destroy the metallic lattice's ability to conduct electricity. Statement (C) is correct.
- They are generally chemically inert and do not follow definite valence/stoichiometry rules (e.g., \(TiC, Mn_4N\)). Statement (D) is correct.
Step 3: Final Answer:
Option (B) is the incorrect characteristic.