The interstitial compounds of transition metals are than the metal itself.

Options

A. softer
B. more malleable
C. harder
D. more metallic

Answer

C

Explanation

Interstitial hydrides, borides, carbides and nitrides are ill-defined compounds formed by a number of transition metals in which small atoms H, B, C and N respectively are accommodated in the voids or interstices in the crystal lattice of the transition element. On account of the filling of vacant spaces and formation of extra bonds, interstitial compounds have following proerties:
(i) They are chemically insert
(ii) They retrain metallic conductivity
(iii) They are very hard. Some borides approach diamond in hardness.
(iv) They have high melting points, higher than those of pure metals