CHEM.2600: Information Retrieval for Chemists

Hill notation is a standard way of writing the formula for any chemical compound.

Hill notation is NOT unique for a compound.

Examples:

1) H₃C(CH₂)₈CH₂NH₂

First, count all Carbon Atoms and record. C₁₀
Second, count all Hydrogen atoms and record: C₁₀H₂₃
Third, determine all other elements in the compound. Count each and record in alphabetical order. C₁₀H₂₃N. 
When determining counts from a structural drawing, CAREFULLY count H atoms!!

2) [(CH₃)₃Si₂]₂NNa

          Counting all the Carbon atoms: C₆
          Counting all the Hydrogen atoms: C₆H₁₈
          Determining all the other elements in the compound.  Count each and record in alphabetical order.

          C₆H₁₈NNaSi₄

_{In Hill notation, if C is present, it always comes first.  It is followed by H, if there are any. All other elements follow C (and H) in alphabetical order.  If there is no C in the compound, all elements are listed in alphabetical order, including H.}