NE = 2+4*(4-2)-8*(1-2)+2*(2-2)]/2 = 2+8-8)/2 = 1
CH3CH2CH2COOH acid butanoic
CH3-CH-COOH acid 2-metilpropanoic
CH3
HCO-O-CH2-CH2-CH3 formiat de propil
HCO-O-CH-CH3 formiat de izopropil
CH3
CH3-CO-O-CH2-CH3 acetat de etil
CH3-CH2-CO-O-CH3 propionat de metil