Answer: heptads

AnswerCrossword Clue
HEPTADSThe Dwarfs et al.
HEPTADSWater polo teams, e.g.
HEPTADSDeadly sins and others
HEPTADSGroups of seven
heptadsHEPTAD, a group of seven
heptadsthe number seven
heptadselement, atom, or group having a valence of seven
heptadsgroup of seven