Question

Which of the following is not an organometallic compound?
A. Ethyl magnesium bromide
B. Tetraethyl lead
C. Sodium ethoxide
D. Trimethylaluminum

Answer 1

The compounds containing metal and carbon bond are termed to be organometallic compounds. The elements like metalloids i.e. silicon, tin etc. are also known to form organometallic compounds. For example, Grignard reagents, tetracarbonyl nickel etc. The general formula of Grignard reagent is $R - Mg - X$; R can be any alkyl or aryl group and X is a halogen atom.

Complete step by step answer:
Let us discuss the options.
Ethyl magnesium bromide
The structural formula can be written as: $C{H_3}C{H_2} - Mg - Br$
Now, from the structural formula, we can say that it is an example of Grignard reagent as it satisfies the general formula. In this structure, R is an ethyl group and X is a bromine or Bromo group.
It also has metal and carbon bonds i.e. the bond between magnesium and carbon of ethyl group. Thus, it is an organometallic compound.
Tetraethyl lead
The structural formula can be written as: ${(C{H_3}C{H_2})_4}Pb$
Now, we can say that it has a metal and carbon bond i.e. the bond between carbon and lead (a metal). Thus, it is an organometallic compound.
Sodium ethoxide
The structural formula can be written as: ${C_2}{H_5}ONa$
Here, we can see that there is no bond between metal and carbon. It has a negative charge on oxygen. So, it is an example of an ionic compound.
Trimethylaluminum
The structure formula can be written as: $A{l_2}{(C{H_3})_6}$
From the formula, we can say that it exists as a dimer. It has metal and carbon bonds. Thus, it is an organometallic compound.

So, the correct option is C.

Note: Ionic compounds can be defined as the compounds which have the formation of cations and anions. For example, sodium chloride, sodium exists as a cation and chloride as anion and they form an ionic compound. That’s why sodium ethoxide is an ionic compound.