Skeletal formula of methyl chloride Recently in The Periodic Table, there was a short discussion regarding this structure:



At first sight, I couldn't figure out what is the structure. After a quick google search, I came to know it is trichloromethane or chloroform (chemspider).
Now, I thought of the structure of dichloromethane and found out to be:



From the structures, It is observed that these are the skeletal formula of tri- and dichloromethane and generally in these structures, the letter C is not denoted, the C-H bond in not denoted and C-Me is denoted by a dash.

Now, following these rules, I was now curious of the skeletal formula of methyl chloride. Is it just a chlorine protruding a bond??



I couldn't find out this structure on the internet and this means that this formula is not valid although, this formula follow the basic rules. Am I wrong in my argument or are the rules vague?

Further, hydrocarbons are the basic skeleton of organic compounds. To draw really complex organic compound, we first have to figure what are the hydrocarbon chains. But still, methane and ethane cannot be drawn using skeletal formula. From propane onwards, you can represent them in skeletal formula.

So, there are certain ambiguities regarding skeletal formula (some simple and basic compounds cannot be drawn) but they are widely preferred. Why is this so?



I searched hard and eventually found out the structural formula of ethane. It is a dash as expected but still, it is a dash. Who would mind that it is ethane?
It is a valid generalisation of the skeletal formula principle to draw chloromethane as you did; you may also see it drawn in the following way:

$$\ce{-Cl}$$

In a similar vein, ethane can be drawn as a simple horizontal (or $60^\circ$ ascending or descending) line, ethene as an equality sign and ethyne as a triple line.

However, the concept of skeletal formulae, which was primarily invented to simplify drawing large, complex molecules, does not extend well to these very small ones. A chlorine atom with a line can be mistaken as $\ce{Cl-}$, a horizontal line as a dash, a double line as an equality sign and so on. Thus, while formally valid, you will not see this representation used often for very small molecules. Typically, it would be used from three explicit atoms upwards — as is the case in your second example, dichloromethane.