Analysis of a Structural Formula for Rings Plus Double Bonds

 

rings plus double bonds =

= (number of carbon) – ((number of hydrogen) / 2) + ((number of nitrogen) / 2) + 1

 

with oxygen not factored into the equation.

 

Additional elements:

(1) halogens: count as hydrogen

(2) silicon: count as carbon

(3) ulfur: count as oxygen

(4) phosphorus: count as nitrogen

 

Interpretation:

• If the resulting number is an integer, then it is an odd-electron species and it is probably the molecular ion.

• If the resulting number has a fractional number, then the ion is an even-electron species and it is probably a fragment ion.