How many letters does the top answer for “a compound containing two chlorine atoms per molecule” have?

The most common answer is dichloride (10 letters).

Crossword clue: a compound containing two chlorine atoms per molecule

1 answer found in Letterora's clue database (Wikidata facts, Open Trivia DB, WordNet and Webster definitions — all licensed sources).

dichloride 10 letters wn-def

a compound containing two chlorine atoms per molecule

any compound containing a chlorine atom 50% similar → chloride

containing two carboxyls per molecule 50% similar → dicarboxylic