Molecular Structure of Hydrazoic Acid from 55 K to Close to the Melting Point Determined with Synchrotron Radiation.

Hydrazoic acid (HN) is the simplest covalent azide, potentially explosive, and strongly toxic with both a low boiling and a low melting point (309 and 193 K, respectively). The monoclinic structure, recently solved by X-ray single-crystal diffraction at 100(2) K, is built up by tetramers (HN) in unique pseudotetragonal layers with N-H···N hydrogen bonds, but with only weak van der Waals bonds between them. As also observed in 2H-graphite, nearly planar layers are stacked parallel to (001) with the sequence A, B, .

Molecular Structure of Isocyanic Acid, HNCO, the Imide of Carbon Dioxide.

Isocyanic acid, HNCO, the imide of carbon dioxide, was prepared by reaction of stearic acid and potassium cyanate (KOCN) at 60 °C in a sealed, thoroughly dried reactor. Interestingly, its crystal structure, solved by X-ray single crystal diffraction at 123(2) K, shows a group-subgroup relation for the NCO anion to carbon dioxide: (for CO, cP12, Pa3̅, a = 5.624(2) Å, 150 K, C-O 1.

Alternative QuEChERS-based modular approach for pesticide residue analysis in food of animal origin.

The approach for pesticide residue analysis in food of animal origin differs strongly from the one established for food of plant origin, as laboratories mainly focus on conventional methods for the analysis of non-polar pesticides known to accumulate in fatty tissues. However, these group-specific methods are very laborious and cost intensive and typically require extraction of fat components followed by extensive clean-up steps to remove matrix constituents. This work highlights the development and validation of a straightforward QuEChERS-derived clean-up procedure enabling facile, precise, and reliable identification and quantitation of pesticide residues in food of animal origin, which can be extended to various other commodities with moderate fat content and applied to replace traditional group-specific methods.

Molecular structure of hydrazoic acid with hydrogen-bonded tetramers in nearly planar layers.

Hydrazoic acid (HN(3))--potentially explosive, highly toxic, and very hygroscopic--is the simplest covalent azide and contains 97.7 wt % nitrogen. Although its molecular structure was established decades ago, its crystal structure has now been solved by X-ray diffraction for the first time.