pentru un compus CaHbOcNdXe
avem
N.E. = (2a+2-b+d-e)/2
S.C. = 4a+b+2c+3d+e
a)
N.E. = (2x3+2-6-2)/2 = 0
S.C. = 3x4+6+2x1 = 20
=> compus real
CH3-CH2-CH2-CHCl
b)
N.E. = (2x4+2-10)/2 = 0
S.C. = 4x4+10x1 = 26
=> compus real
CH3-CH2-CH2-CH3
c)
N.E. = (2x4+2-9-1)/2 = 0
S.C. = 4x4+9x1+1x1 = 26
=> compus real
CH3-CH2-CH2-CH2-Br
d)
N.E. = (2x2+2-7+1)/2 = -1
S.C. = 2x4+7x1+1x3 = 18
=> compusul NU exista