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The reactivity of Bi_n⁻clusters (n= 2 to 30) with O₂is found to display even-odd alternations. The open-shell even-sized Bi_n⁻clusters are more reactive than the closed-shell odd-sized clusters, except Bi₁₈⁻, which exhibits no observable reactivity toward O₂. We have investigated the structure and bonding of Bi₁₈⁻to understand its remarkable resistance to oxidation. We find that the most stable structure of Bi₁₈⁻consists of two Bi₈cages linked by a Bi₂dimer, where each atom is bonded to three neighboring atoms. Chemical bonding analyses reveal that each Bi uses its three 6pelectrons to form three covalent bonds with its neighbors, resulting in a Bi₁₈⁻cluster without any dangling bonds. We find that the robust Bi₁₈framework along with the totally delocalized unpaired electron is responsible for the surprising inertness of Bi₁₈⁻toward O₂. The Bi₁₈framework is similar to that in Hittorf’s phosphorus, suggesting the possibility to create bismuth nanoclusters with interesting structures and properties. 

Abstract Phytoplankton blooms in coastal oceans can be beneficial to coastal fisheries production and ecosystem function, but can also cause major environmental problems 1,2 —yet detailed characterizations of bloom incidence and distribution are not available worldwide. Here we map daily marine coastal algal blooms between 2003 and 2020 using global satellite observations at 1-km spatial resolution. We found that algal blooms occurred in 126 out of the 153 coastal countries examined. Globally, the spatial extent (+13.2%) and frequency (+59.2%) of blooms increased significantly ( P  < 0.05) over the study period, whereas blooms weakened in tropical and subtropical areas of the Northern Hemisphere. We documented the relationship between the bloom trends and ocean circulation, and identified the stimulatory effects of recent increases in sea surface temperature. Our compilation of daily mapped coastal phytoplankton blooms provides the basis for global assessments of bloom risks and benefits, and for the formulation or evaluation of management or policy actions.