arene c
allenic C [$([CX2](=C)=C)]
vinylic C [$([CX3]=[CX3])]
acetylenic C [$([CX2]#C)]
carbonyl [$([CX3]=[OX1]),$([CX3+]-[OX1-])]
aldeyhde [CX3H1](=O)[#6]
amide [NX3][CX3](=[OX1])[#6]
carboxylic acid [CX3](=O)[OX2H1]
ester [#6][CX3](=O)[OX2H0][#6]
ketone [#6][CX3](=O)[#6]
ether [OD2]([#6])[#6]
azo general [#7]
amine [NX3;H2,H1;!$(NC=O)]
enamine [NX3][CX3]=[CX3]
imine [$([CX3]([#6])[#6]),$([CX3H][#6])]=[$([NX2][#6]),$([NX2H])]
nitrate [$([NX3](=[OX1])(=[OX1])O),$([NX3+]([OX1-])(=[OX1])O)]
nitrile [NX1]#[CX2]
nitro [$([NX3](=O)=O),$([NX3+](=O)[O-])][!#8]
alcohol [#6][OX2H]
enol [OX2H][#6X3]=[#6]
phenol [OX2H][cX3]:[c]