What are electron-deficient compounds? Are $BCl_3$ and $SiCl_4$ electron-deficient species?

(N/A) Electron-deficient compounds are those in which the central atom has an incomplete octet,meaning it has fewer than $8$ electrons in its valence shell.
$(i)$ $BCl_3$:
Boron $(B)$ has $3$ valence electrons. Upon forming $3$ covalent bonds with chlorine atoms,the total number of electrons around the boron atom becomes $6$. Since it has fewer than $8$ electrons,$BCl_3$ is an electron-deficient species.
$(ii)$ $SiCl_4$:
Silicon $(Si)$ has $4$ valence electrons. Upon forming $4$ covalent bonds with $4$ chlorine atoms,the total number of electrons around the silicon atom becomes $8$. Since it has a complete octet,$SiCl_4$ is not an electron-deficient species.