Chemistry 130 course documents archive
Molecular formula search tips
To search by molecular formula, first summarize the line formula and then arrange elements in Hill System Order.
| Line formula | Summarized formula | Hill System order |
|---|---|---|
| BrCH2COOH | C2H3O2Br | C2H3BrO2 |
Definition of Hill System order
- Carbon first, Hydrogen second, and all remaining elements, including deuterium and tritium, in alphabetical order
- If no carbon is present, put all elements in alphabetical order
- Indicate the number after each element (ignore the fact that the numbers are subscripts)
Case-sensitivity of element symbols
- While the molecular formulas of most resources on campus are not case-sensitive (element symbols may be typed in
either upper or lower case letters), the element symbols ARE case-sensitive in:
- Chapman and Hall Chemical Dictionaries on CD-ROM (Organic Compounds, Natural Products, and Inorganic & Organometallic Compounds)
- INSPEC (molecular formulas are put in the Chemical or CH Index)
- For example, in the formula above, Bromine would need to be searched as Br.