A student performed the Beilstein test within a chemical fume hood by inserting a looped end of a copper wire into the hottest part of a flame on a Bunsen burner so the copper loop glowed. Once it glowed, they removed the copper loop and allowed it to cool. Finally, they dipped the copper loop into a test tube containing the unknown liquid and quickly placed the wet loop into the tip of the flame. The student observed an intense green flash within the flame. What compound is most likely the unknown