Which of the following is correct for d-block metals ?

Options

A. They form exclusively covalent compounds
B. They exclusively form coordination compounds but no simple compounds
C. They may form either ionic or covalent compounds depending on the condition.
D. They form only ionic compounds.

Answer

C

Explanation

The ionization enthalpies of d-block metals are greater than those of s-block metals but are lower than those of p-block elements. This implies that the d-block elements are less electropositive than s-block elements but are more electropositive than p-block elements but are more electropositive than p-block elements. Consequently, they may for either ionic or covalent bonds depending on the condition. Generally, the compounds formed in lower valence states are ionic but those in higher valence states are convalent. The first row (3d) elements have many more ionic compounds (on account of relatively low ionization enthalpies) than elements in the second (4d) and third (5d) rows.