The flow of materials and energy
through society is an integral
but poorly visible element of global sustainability agendas such as
the Planetary Boundaries Framework and the UN Sustainable Development
Goals (UNSDG). Given that the primary activities of chemistry are
to analyze, synthesize, and transform matter, the practice of chemistry
has a great deal to contribute to sustainability science, which in
turn should play an increasingly important role in reshaping the practice
of chemistry. Success in integrating sustainability considerations
into the practice of chemistry implies a substantial role for chemistry
education to better equip students to address the sustainability of
earth and societal systems. Building on the framework of the IUPAC
Systems Thinking in Chemistry Education (STICE) project, we develop
approaches to using systems thinking to educate students about the
molecular basis of sustainability, to assist chemistry to contribute
meaningfully and visibly toward the attainment of global sustainability
agendas. A detailed exemplar shows how ubiquitous coverage in general
chemistry courses of the Haber–Bosch process for the synthesis
of ammonia could be extended using systems thinking to consider the
complex interplay of this industrial process with scientific, societal,
and environmental systems. Systems thinking tools such as systems
thinking concept map extension (SOCME) visualizations assist in highlighting
inputs, outputs, and societal consequences of this large-scale industrial
process, including both intended and unintended alterations to the
planetary cycle of nitrogenous compounds. Strategies for using systems
thinking in chemistry education and addressing the challenges its
use may bring to educators and students are discussed, and suggestions
are offered for general chemistry instructors using systems thinking
to educate about the molecular basis of sustainability.
The salt, [F5TeN(H)Xe][AsF6], has been synthesized in the natural abundance and 99.5% 15N-enriched forms. The F5TeN(H)Xe+ cation has been obtained as the product of the reactions of [F5TeNH3][AsF6] with XeF2 (HF and BrF5 solvents) and F5TeNH2 with [XeF][AsF6] (HF solvent) and characterized in solution by 129Xe, 19F, 125Te, 1H, and 15N NMR spectroscopy at -60 to -30 degrees C. The orange [F5TeN(H)Xe][AsF6] and colorless [F5TeNH3][AsF6] salts were crystallized as a mixture from HF solvent at -35 degrees C and were characterized by Raman spectroscopy at -165 degrees C and by X-ray crystallography. The crystal structure of the low-temperature phase, alpha-F5TeNH2, was obtained by crystallization from liquid SO2 between -50 and -70 degrees C and is fully ordered. The high-temperature phase, beta-F5TeNH2, was obtained by sublimation at room temperature and exhibits a 6-fold disorder. Decomposition of [F5TeN(H)Xe][AsF6] in the solid state was rapid above -30 degrees C. The decomposition of F5TeN(H)Xe+ in HF and BrF5 solution at -33 degrees C proceeded by fluorination at nitrogen to give F5TeNF2 and Xe gas. Electronic structure calculations at the Hartree-Fock and local density-functional theory levels were used to calculate the gas-phase geometries, charges, Mayer bond orders, and Mayer valencies of F5TeNH2, F5TeNH3+, F5TeN(H)Xe+, [F5TeN(H)Xe][AsF6], F5TeNF2, and F5TeN2- and to assign their experimental vibrational frequencies. The F5TeN(H)Xe+ and the ion pair, [F5TeN(H)Xe][AsF6], systems were also calculated at the MP2 and gradient-corrected (B3LYP) levels.
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