ACS sesquicentennial

Welcome to this month’s crossword, constructed by George Barany, professor emeritus of chemistry at the University of Minnesota Twin Cities, and Irene Cesa, retired chemist from Wheaton, Illinois. They thank Marcia Brott, Michael Hanko, and Eric Block for test solving and editorial suggestions. C&EN thinks that American Chemical Society members who solve the puzzle will appreciate anew the living legacy of service and contributions of ACS as it celebrates its 150-year anniversary. ACS-themed clues are bolded, and an accompanying article online gives background information to these and some other clues.