Quadruple bond electrons (σπδδ*) has an Os–Os triple bond and a staggered geometry. Many other compounds with quadruple bonds between transition metal atoms have been described, often by Cotton and his coworkers. Isoelectronic with the dirhenium compound is the salt K[MoCl] (potassium octachlorodimolybdate). An example of a ditungsten compound with a quadruple bond is ditungsten tetra(hpp). Quadruple bonds between atoms of main group elements are unknown. Molecular orbital theory shows that there are two sets of paired electrons in the sigma system (one bonding, one antibonding), and two sets of paired electrons in a degenerate π-bonding set of orbitals. This adds up
Owned-and-operated television stations in the United States opened up a new spectrum of frequencies on the UHF dial (channels 14–83) for terrestrial television. As an incentive for companies to operate UHF stations, the FCC relaxed the ownership limit for a given entity from five to seven stations, provided that no more than five were on the VHF dial. With this opportunity to expand its roster of O&Os, NBC bought WBUF-TV (channel 17) in Buffalo in 1955 and WKNB-TV (channel 30) in New Britain, Connecticut (near Hartford) in 1957, and changed WKNB's call letters to WNBC-TV (the present-day WNBC in New York City used the WRCA-TV callsign from