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This week The Alchemist chills out with a Bose-Einstein condensate (BEC) that defies Newton's second law, learns how fungi can still be a source of relief, sees how NMR corrects the chemical record, and discovers a flashy way to sinter superhard ceramics and a simpler synthesis of olefins (alkenes). Finally, an Italian award for inorganic chemistry.

A Bose-Einstein condensate formed from rubidium atoms held at very close to absolute zero behaves as if it has negative mass according to US scientists. We are all familiar with positive and negative electrical charges, but the notion of a negative counterpart for matter has until now remained a purely theoretical construct. Now, Michael Forbes of Washington State University and his colleagues have demonstrated a material that when "pushed" accelerates towards to direction in which that force is coming rather than moving away. This seems to contradict Newton's second law of motion, but in modern physics is perfectly acceptable given a negative mass as the team has observed.

Fungi have been seen as a major source of natural products for many years, not least bactericidal compounds. Now, a team at Chalmers University in Sweden have sequenced the genomes of nine different types of Penicillium species with a view to find novel antibiotics. We found that the fungi has an enormous, previously untapped, potential for production of new antibiotics and other bio-active compounds, such as cancer medicines, explains team member Jens Christian Nielsen. More than 1000 biosynthetic pathways were discovered, which shows the enormous potential of this approach to searching for bio-active compounds with putative pharmaceutical properties.

The chemical structure of a potentially important marine natural product has been revised based on nuclear magnetic resonance (NMR) spectroscopy and theoretical modeling of the compound. Mary Garson and Gregory Pierens of the University of Queensland, in Brisbane, Australia, and their colleagues in Indonesia and the USA recently reported a stereochemical structural elucidation of the meroterpenoid acremine P from a particular strain of the fungus Acremonium persicinum which was found in the Australian marine sponge Anomoianthella rubra. The revision will not only allow research into this class of compound to move forward it serves as an invaluable reminder that computational studies can help inform structure evaluation and flag up putative incorrect assignments.

Flash spark plasma sintering is a new technique developed by scientists at the US Department of Energy for making ceramics. In this new process, incredibly hard ceramics can be formed without losing microstructural features and so retaining important properties. The technique uses pressure to preclude damaging thermal runaway during sintering and has been shown to work with superhard silicon carbide. The process used sacrificial dies to heat pre-compacted SiC powder specimens to a critical temperature before applying voltage to the powder volume for sintering. Scanning electron microscopy shows how densification takes place almost instantaneously with limited grain growth.

Decarboxylative alkenylation can readily convert carboxylic acids into alkenes, thanks to research by chemists at The Scripps Research Institute in California, USA. Phil Baran's team suggests the simplified method really changes the way he thinks about making molecules. Baran's work displaces the multistep reactions of decades past, including the Wittig reaction invented in 1954. “Organic chemists have endured this burdensome 'analog' process for decades with little complaint,” Baran says. “Now with this new method we’re bringing olefination into the digital era.”

Guy Bertrand of the University of California San Diego is the 2017 recipient of the Luigi Sacconi Medal from the Italian Chemical Society or inorganic chemistry. The medal is given each year for outstanding contributions to the field. Bertrand and his colleagues have worked on making stable carbenes and their non-carbon analogs, including nitrenes and phosphinidenes.