Nitrogen fixation and the cycles of nitrogen on Earth are key to life as we know it and are critical to both modern agriculture and sustaining natural ecosystems.Despite its importance,there is still much we do not kn...Nitrogen fixation and the cycles of nitrogen on Earth are key to life as we know it and are critical to both modern agriculture and sustaining natural ecosystems.Despite its importance,there is still much we do not know about the processes of transforming nitrogen in natural systems.Nitrogen transformation into ammonia is fundamentally a chemical reduction reaction.It can occur catalytically where there is a source of electrons and a catalyst,or directly where a substrate is concomitantly oxidized,providing the source of electrons directly.In this review we explore the chemistry of iron sulfides to understand the reactions they mediate when they interact with nitrogen species,both as direct reductants and as catalysts,as well as the relationship between catalysis and reduction.In parallel it also describes the chemistry of Earth from a protoplanet through to modern times of relevance to understanding nitrogen speciation and historical drivers of these transformations,with a focus on how the pressures and temperatures on Earth may have impacted nitrogen,iron,sulfur and related species.We explore how iron sulfides can both directly and catalytically mediate some chemical reduction reactions and explore how this may have been significant in life's origins.展开更多
Crystalline borates are a rich source of diverse optical materials.Here,a rare earth borate fluoride,Sc_(2)F_(2)(B_(2)O_(5)),has been obtained by a conventional hydrothermal reaction.It is unlike other rare earth bora...Crystalline borates are a rich source of diverse optical materials.Here,a rare earth borate fluoride,Sc_(2)F_(2)(B_(2)O_(5)),has been obtained by a conventional hydrothermal reaction.It is unlike other rare earth borate fluorides synthesized under harsh conditions.In the layered structure of Sc_(2)F_(2)(B_(2)O_(5)),ScO_(4)F_(2) octahedra and ScO_(5)F_(2) pentagonal bipyramids connect to each other to form[Sc_(4)O_(10)F_(4)]_(∞) frameworks,which are further linked by B_(2)O_(5)^(4−)anion groups.Specifically,Sc_(2)F_(2)(B_(2)O_(5))does not belong to any types of reported rare earth borate fluoride.More attractively,this compound displays a deep ultraviolet cutoff edge(<200 nm)and very large birefringence(0.19)at 1064 nm based on theoretical calculations.The outstanding birefringence can be seen to originate from the synergistic effect of B_(2)O_(5) and ScO_(n)F_(2) groups when analysed for their polarizability anisotropy-weighted electron density(PAWED).展开更多
基金support for this project from the Australian Research Council via DP 200101878。
文摘Nitrogen fixation and the cycles of nitrogen on Earth are key to life as we know it and are critical to both modern agriculture and sustaining natural ecosystems.Despite its importance,there is still much we do not know about the processes of transforming nitrogen in natural systems.Nitrogen transformation into ammonia is fundamentally a chemical reduction reaction.It can occur catalytically where there is a source of electrons and a catalyst,or directly where a substrate is concomitantly oxidized,providing the source of electrons directly.In this review we explore the chemistry of iron sulfides to understand the reactions they mediate when they interact with nitrogen species,both as direct reductants and as catalysts,as well as the relationship between catalysis and reduction.In parallel it also describes the chemistry of Earth from a protoplanet through to modern times of relevance to understanding nitrogen speciation and historical drivers of these transformations,with a focus on how the pressures and temperatures on Earth may have impacted nitrogen,iron,sulfur and related species.We explore how iron sulfides can both directly and catalytically mediate some chemical reduction reactions and explore how this may have been significant in life's origins.
基金support from the National Natural Science Foundation of China(22101248)the National Key Laboratory Development Fund(20210002)the Lvyangjinfeng Talent Program of Yangzhou(YZLYJFJH2021YXBS083).
文摘Crystalline borates are a rich source of diverse optical materials.Here,a rare earth borate fluoride,Sc_(2)F_(2)(B_(2)O_(5)),has been obtained by a conventional hydrothermal reaction.It is unlike other rare earth borate fluorides synthesized under harsh conditions.In the layered structure of Sc_(2)F_(2)(B_(2)O_(5)),ScO_(4)F_(2) octahedra and ScO_(5)F_(2) pentagonal bipyramids connect to each other to form[Sc_(4)O_(10)F_(4)]_(∞) frameworks,which are further linked by B_(2)O_(5)^(4−)anion groups.Specifically,Sc_(2)F_(2)(B_(2)O_(5))does not belong to any types of reported rare earth borate fluoride.More attractively,this compound displays a deep ultraviolet cutoff edge(<200 nm)and very large birefringence(0.19)at 1064 nm based on theoretical calculations.The outstanding birefringence can be seen to originate from the synergistic effect of B_(2)O_(5) and ScO_(n)F_(2) groups when analysed for their polarizability anisotropy-weighted electron density(PAWED).
