Electron-deficient compounds are chemical compounds with incomplete octets that tend to acquire 1 or more electrons to complete their octet configurations.
Silicon has 4 valence electrons (its electronic configuration is 2s2 2p2). Its octet is completed after forming four single bonds with four different chlorine atoms. Therefore, SiCl4 is not an electron-deficient compound.
BCl3 is a good example of an electron-deficient compound. Since boron has three valence electrons, it forms 3 single bonds with chlorine, giving the boron atom a total of 6 electrons in the outermost shell.However, it is still short of 2 electrons to complete its octet