.H+

Increase number of total hydrogens (total number of hydrogen substituents)

.H-

Decrease number of total hydrogens (total number of hydrogen substituents)

.v+

Increase number of valence (total bond order)

.v-

Decrease number of valence (total bond order)

.X+

Increase number of connections (number of substituents including hydrogens)

.X-

Decrease number of connections (number of substituents including hydrogens)

.R-

Increase number of rings (number of rings the atom is a member of)

.R+

Decrease number of rings (number of rings the atom is a member of)

.r+

Increase smallest ring size (size of the smallest ring the atom is a member of)

.r-

Decrease smallest ring size (size of the smallest ring the atom is a member of)

.rb+

Increase ring bond count (number of ring bonds next to the atom)

.rb-

Decrease ring bond count (number of ring bonds next to the atom)

.s+

Increase substitution count (number of non-hydrogen and isotopic hydrogen substituents)

.s-

Decrease substitution count (number of non-hydrogen and isotopic hydrogen substituents)

.h+

Increase number of implicit hydrogens (number of implicit hydrogen substituents)

.h-

Decrease number of implicit hydrogens (number of implicit hydrogen substituents)

.D+

Increase degree (equivalent to substitution count: number of non-hydrogen and isotopic hydrogen substituents)

.D-

Decrease degree (equivalent to substitution count: number of non-hydrogen and isotopic hydrogen substituents)

.u

Mark as unsaturated atom (atom has double, triple or aromatic bond)

.a/A

Mark as aromatic/aliphatic (has aromatic bond)