The title hepta­nuclear alkoxido(oxido)vanadium(V) oxide cluster complex, [V7(C10H19O)O17(C18H24N2)3]·CH3CN, was obtained by the reaction of [V8O20(C18H24N2)4] with 4-tert-butyl­cyclo­hexa­nol (mixture of cis and trans) in a mixed CHCl3/CH3CN solvent. The complex has a V7O18N6 core with approximately Cs symmetry, which is composed of two VO4 tetra­hedra, two VO6 octa­hedra and three VO4N2 octa­hedra. In the crystal, these complexes are linked together by weak inter­molecular C—H⋯O hydrogen bonds between the 4,4'-di-tert-butyl-2,2'-bi­pyridine ligand and the V7O18N6 core, forming a one-dimensional network along the c-axis direction. Besides the complex, the asymmetric unit contains one CH3CN solvent mol­ecule. The contribution of other disordered solvent mol­ecules to the scattering was removed using the SQUEEZE option in PLATON [Spek (2015). Acta Cryst. C71, 9–18]. The unknown solvent mol­ecules are not considered in the chemical formula and other crystal data.

The title hydrated mol­ecular salt (systematic name: tetra-n-butyl­ammonium 2,6-dioxo-1,2,3,6-tetra­hydro­pyrimidine-4-carboxyl­ate monohydrate), C16H36N+·C5H3N2O4−·H2O, crystallizes with N—H⋯O and O—H⋯O hydrogen-bonded double-stranded anti­parallel ribbons consisting of the hydro­philic orotate monoanions and water mol­ecules, separated by the bulky hydro­phobic cations. The hydro­phobic and hydro­philic regions of the structure are joined by weaker non-classical C—H⋯O hydrogen bonds. An accurate structure analysis conducted at T = 100 K is compared to a lower-resolution less accurate determination using data measured at T = 295 K. The results of both analyses are evaluated using a knowledge-based approach, and it is found that the less accurate room-temperature structure analysis provides geometric data that are similar to those derived from the accurate low-temperature analysis, with both sets of results consistent with previously analyzed structures. A minor disorder of one methyl group in the cation at low temperature was found to be slightly more complex at room temperature; while still involving a minor fraction of the structure, the disorder at room temperature was found to require a non-routine treatment, which is described in detail.

Silicon nanowire-based sensors find many applications in micro- and nano-electromechanical systems, thanks to their unique characteristics of flexibility and strength that emerge at the nanoscale. This work is the first study of this class of micro- and nano-fabricated silicon-based structures adopting the scanning X-ray diffraction microscopy technique for mapping the in-plane crystalline strain (∊044) and tilt of a device which includes pillars with suspended nanowires on a substrate. It is shown how the micro- and nanostructures of this new type of nanowire system are influenced by critical steps of the fabrication process, such as electron-beam lithography and deep reactive ion etching. X-ray analysis performed on the 044 reflection shows a very low level of lattice strain (<0.00025 Δd/d) but a significant degree of lattice tilt (up to 0.214°). This work imparts new insights into the crystal structure of micro- and nanomaterial-based sensors, and their relationship with critical steps of the fabrication process.

Determining the locations of future highways and roads in countries with tropical rainforests will be the greatest single factor in influencing future forest loss, fragmentation and degradation. In broad terms, roads can be thought of as the enemies of rainforests. By spreading people out across the forest, roads inherently promote rapid and widespread deforestation.

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Snowflake Study through Photomicrography, 1890 Wilson A. Bentley became fascinated with the crystalline structure of individual snowflakes on his parent’s Vermont farm. By adapting a […]

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To prevent the loss of Inupiaq words for ice and the knowledge that it embodies, Igor Krupnik, ethnologist at the Arctic Studies Center of the National Museum of Natural History, and Wales native Winton Weyapuk Jr., recently compiled an illustrated dictionary of some 120 Kingikmiut words used in Wales to describe different types of ice.

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This Jupiter-sized world reflects less than one percent of the light that falls on it, making it blacker than any planet or moon in our solar system.

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A box jellyfish from the Caribbean appears to have recently become established in the red mangroves of Florida near Boca Raton.

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The snakes are not only eating the area’s birds, but also the birds’ eggs straight from the nest.

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To celebrate its 22nd anniversary in orbit, the Hubble Space Telescope has released a dramatic new image of the star-forming region 30 Doradus, also known […]

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Accumulations of drifting snow are the most plausible explanation for the presence of a number of puzzling alluvial fan deposits found inside large impact craters on Mars

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A new study finds that since 1985, half of Australia's Great Barrier Reef coral has died.

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Our solar system seems like a neat and orderly place, with small, rocky worlds near the Sun and big, gaseous worlds farther out, all eight […]

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Astronomers have discovered a transiting exoplanet with the longest known year. Kepler-421b circles its star once every 704 days. In comparison, Mars orbits our Sun […]

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In the United States, natural-gas production from shale rock has increased by more than 700 percent since 2007. Yet scientists still do not fully understand […]

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Giant pandas. Grizzlies. Polar bears. You’ve probably heard a lot about these bear species, but what about Andean bears? To the Quechua and Aymara, the […]

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Scientists examining the stomach contents of invasive lionfish caught on the inner barrier reef of Belize have discovered that nearly half of the diet of […]

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Surplus mustard gas canisters and unexploded bombs dumped in the Pacific Ocean near Hawaii after WWII, have become, scientists say, a potential reef that is […]

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Now here is something to ruminate on. About 85 percent of the methane produced by a cow comes out of its mouth as burps. The […]

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Snowstorms and blizzards send people to raid supermarkets and prepare their homes for days of staying indoors, but how do the animals at the Smithsonian’s […]

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A social media celebrity was born last week when the bright lights and camera of NOAA’s remotely operated vehicle Deep Discoverer zoomed in on a […]

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Space: the final frontier. These are the voyages of the Starship Enterprise…and you know the rest, probably even if you’re not a huge fan of […]

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Perhaps puppies cuddling in the snow makes winter’s bite not so unpleasant? In one of his most charming designs, Japanese artist Isoda Koryūsai (1735–1790) depicted […]

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The Smithsonian Research Online program recently surpassed the mark of 10,000 publications in the Digital Repository. This collection of digital publications by Smithsonian staff represents a broad review of research done by researchers at the Institution.

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The three male cheetahs that left the Zoo's D.C. campus in 2009 returned in November and are now on exhibit. The five-and-a-half-year-old brothers―Draco, Granger, and Zabini, named after characters in the Harry Potter stories―have been living at the Zoo's Smithsonian Conservation Biology Institute's Cheetah Science Facility in Front Royal, Virginia.

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The post How do we know if dinosaurs cared for their young? Smithsonian curator Matthew Carrano reveals the fossil evidence. appeared first on Smithsonian Insider.

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The post Smithsonian planetary scientist Tom Watters explains how he knows the moon is shrinking appeared first on Smithsonian Insider.

Jan. 6, 2015—As the year’s first blanket of snow coated the Washington, D.C. area today, giant panda Bao Bao at the Smithsonian’s National Zoological Park […]

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Why do we love orchids so much? Tom Mirenda, Smithsonian Gardens orchid collection specialist, believes it is partly because orchids seem to look back at […]

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To catch lizards on the offshore islands close to St. Croix in the Caribbean, Smithsonian herpetologist Nicole Angeli uses a lasso of thread looped at […]

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The cationic cyclo­metallated iridium(III) complex [Ir(C9H7N2)2(C12H8N2)](PF6) has been synthesized and crystallized by the inter-diffusion method. It contains an unknown number of solvent mol­ecules and has a different space-group symmetry (C2/c) structure than its solvatomorph (P21/c).

The cationic complex in the title compound, [Ir(C9H7N2)2(C12H8N2)]PF6, comprises two phenylpyrazole (ppz) cyclometallating ligands and one 1,10-phenanthroline (phen) ancillary ligand. The asymmetric unit consists of one [Ir(ppz)2(phen)]+ cation and one [PF6]− counter-ion. The central IrIII ion is six-coordinated by two N atoms and two C atoms from the two ppz ligands as well as by two N atoms from the phen ligand within a distorted octahedral C2N4 coordination set. In the crystal structure, the [Ir(ppz)2(phen)]+ cations and PF6− counter-ions are connected with each other through weak intermolecular C—H...F hydrogen bonds. Additional C—H...π interactions between the rings of neighbouring cations consolidate the three-dimensional network. Electron density associated with additional disordered solvent molecules inside cavities of the structure was removed with the SQUEEZE procedure in PLATON [Spek (2015). Acta Cryst. C71, 9–18]. The given chemical formula and other crystal data do not take into account the unknown solvent molecule(s). The title compound has a different space-group symmetry (C2/c) from its solvatomorph (P21/c) comprising 1.5CH2Cl2 solvent molecules per ion pair.

Long-term population trends for some North American pollinators -- bees, birds, bats, and other animals and insects that spread pollen so plant fertilization can occur -- are demonstrably downward, says a new report from the National Research Council.

The search for life elsewhere in the solar system and beyond should include efforts to detect what scientists sometimes refer to as weird life -- that is, life with an alternative biochemistry to that of life on Earth -- says a new report from the National Research Council.

As of today all PDF versions of books published by the National Academies Press will be downloadable to anyone free of charge. This includes a current catalog of more than 4,000 books plus future reports produced by the Press.

Educational and business leaders want todays students both to master school subjects and to excel in areas such as problem solving, critical thinking, and communication

A new report from the National Research Council has upheld the listing of formaldehyde as “known to be a human carcinogen” in the National Toxicology Program 12th Report on Carcinogens (RoC).

Ovarian cancer should not be categorized as a single disease, but rather as a constellation of different cancers involving the ovary, yet questions remain on how and where various ovarian cancers arise, says a new congressionally mandated report from the National Academies of Sciences, Engineering, and Medicine.

Improved understanding of the coupled natural-human coastal system will help promote resilience of coastal communities and ecosystems under rapidly changing environmental conditions and support informed decision-making, says a new report from the National Academies of Sciences, Engineering, and Medicine.

The Gulf Research Program (GRP) of the National Academies of Sciences, Engineering, and Medicine is now accepting applications for its Early-Career Research Fellowships and Science Policy Fellowships for 2019.