• # question_answer 17) What are electron deficient compounds? Are $BC{{l}_{3}}$and $SiC{{l}_{4}}$ electron deficient species? Explain.

The compounds in which the central element possesses incomplete octet, i.e., less than 8 electrons in the valence shell are termed electron deficient compounds. $BC{{l}_{3}}$ Is an electron deficient compound as the central boron atom has six electrons in its valence shell. It can accept two more electrons to complete its octets It reacts with $_{\centerdot }^{\centerdot }N{{H}_{3}}$ to form an addition compound. $C{{l}_{3}}B+N{{H}_{3}}\to C{{l}_{3}}B\leftarrow N{{H}_{3}}$ $SiC{{l}_{4}}$is not an electron deficient compound as silicon atom has complete octet in its valence shell. However, due to the presence of d-orbitals, it can expand its octet and forms species like${{[SiC{{l}_{6}}]}^{2-}}$.