F. Albert Cotton and his coworkers at Texas A&M University surprised chemists in 1964 with evidence that the [Re2Cl8]2 ion contained the first known multiple bond between two metal atoms. Not only was it a multiple bond, it was an unprecedented quadruple bond. Cotton convinced the world that he was right, and inorganic chemistry hasn't been the same since. Now, Philip P. Power at the University of California, Davis, and his coworkers report evidence for the first "quintuple" bond between two metal atoms in the dichromium complex, RCrCrR, where R is a bulky terphenyl ligand (Science, published online Sept. 22,...