Crossword puzzle clue "molecular link with two pairs of electrons shared by two atoms"

OCTET, a composition for eight players, also OCTETT, OCTETTE

ION, an electrically-charged particle formed by loss or gain of electrons by an atom

ORBITAL, an orbit

DUO, two people considered a pair for a specific reason

a practice or belief passed on other than by genes

a film with two molecular layers

of acids, having two replaceable hydrogen atoms