Question

What are electron deficient compounds? Are BCl₃ and SiCl₄ electron deficient species? Explain

Answer 1

In an electron-deficient compound, the octet of electrons is not complete, i.e., the central metal atom has an incomplete octet. Therefore, it needs electrons to complete its octet.

1. BCl₃
   BCl₃ is an appropriate example of an electron-deficient compound. B has 3 valence electrons. After forming three covalent bonds with chlorine, the number of electrons around it increases to 6. However, it is still short of two electrons to complete its octet.
2. SiCl₄
   The electronic configuration of silicon is ns² np². This indicates that it has four valence electrons. After it forms four covalent bonds with four chlorine atoms, its electron count increases to eight. Thus, SiCl₄ is not an electron-deficient compound.