The power of unintended consequences : strategic naïvety, China and the end of the US empire

The decline of major global empires has frequently rested upon an act of strategic naïvety. Such an action or decision, although innocuous at the time, results many decades later in those empires collapsing. History is punctuated by examples of great powers that have misjudged the intentions of a rising power, leading to a highly adversarial relationship. Such unintended consequences can be seen in United States policy towards China, which has allowed Beijing to emerge as a clear competitor that is threatening to usurp US hegemony. This article considers these dynamics across seven major empires, dating from ancient Carthage circa 814 BC to modern day Pax Americana. By connecting the past to the present, we find that comparable acts of strategic naïvety by other empires are now increasingly evident in current US-China relations, and which have often occurred for similar reasons.Publisher PDFPeer reviewe

Controlling crystal growth with modifiers

Modifying crystal growth processes using additives is a well established approach to solvingproblems in many processes. Nature also makes extensive use of crystalline inorganicstructures modified by soluble and insoluble organic materials. This Highlight discusses someof the recent and interesting developments in this area, with an emphasis on the control ofcrystal growth rates, covering both inhibitors and the lesser known promoters of crystalgrowth. Hybrid materials resulting from the incorporation of modifiers into crystallinestructures are also discussed, with an emphasis on non-classical crystallisation mechanisms,involving the oriented attachment of nanoparticles

Investigation of growth rate dispersion in lactose crystallisation by AFM

α-Lactose monohydrate crystals have been reported to exhibit growth rate dispersion (GRD). Variation in surface dislocations has been suggested as the cause of GRD, but this has not been further investigated to date. In this study, growth rate dispersion and the change in morphology were investigated in situ and via bottle roller experiments. The surfaces of the (0 1 0) faces of crystals were examined with Atomic Force Microscopy. Smaller, slow growing crystals tend to have smaller (0 1 0) faces with narrow bases and displayed a single double spiral in the centre of the crystal with 2 nm high steps. Additional double spirals in other crystals resulted in faster growth rates. Large, fast growing crystals were observed to have larger (0 1 0) faces with fast growth in both the a and b directions (giving a broader crystal base) with macro steps parallel to the (c direction). The number and location of spirals or existence of macro steps appears to influence the crystal morphology, growth rates and growth rate dispersion in lactose crystals

The impact of oxalate ions on barium sulfate crystallization

In this manuscript we investigate the impact of oxalate ions on the crystallization of barium sulfate. The organic anion, oxalate, was found to inhibit both nucleation and growth according to atomic force microscopy measurements and dynamic light scattering data. Raman confocal imaging was used to try and determine how the oxalate interacts with the barium sulfate surface. It was found that barium oxalate is only seen at very high oxalate concentrations. At lower concentrations no direct evidence for the presence of oxalate was observed, however, the most probable mode of action for oxalate is via adsorption onto the barium sulfate surface including into key kink or step sites, impacting growth

Experimental and Computational Studies of Incorporation of Cyano Transition Metal Complexes in Potassium Chloride Crystals

Experimental and computational studies of the incorporation of hexacyanoferrate(II), hexacyanocobaltate(III), and hexacyanoferrate(III) into potassium chloride crystals are described. The experimental results showed that the extent of incorporation follows the trend, hexacyanoferrate(II) >> hexacyanoferrate(III) > hexacyanocobaltate(III). Computational modelling produced replacement energies that match the experimental trend. The calculated geometry of the incorporated complexes was also found to match well with previous experimental results

Investigating vaterite phase stabilisation by a tetrazole molecule during calcium carbonate crystallisation

Tetrazole compounds have recently been found to impact on crystal morphology but in a manner different from that of carboxylate molecules. One such molecule was found to stabilise vaterite and this was investigated by assessing the impact of systematic changes on its structure. It was found that both the tetrazole and the formyl functionalities were required for vaterite stabilisation. The mechanism of stabilisation appears to be via inhibition of vaterite dissolution

A brief review of Cn-symmetric calixarenes and resorcinarenes

Calixarene and resorcinarene macrocycles are renowned for their ability to form inclusion complexes or act as molecular scaffolds. The addition of chirality to these non-planar molecules is an exciting enhancement of their already robust potential, offering much promise as ligands for chiral catalysis and enantioselective separations. Chiral calixarenes can be produced by the attachment of a chiral moiety or by the placement of an achiral functionality on the macrocyclic structure so as to render it asymmetric. The latter method is particularly intriguing, often resulting in molecules which have Cn dissymmetry. This review describes examples of the Cn-dissymmetric calixarenes and resorcinarenes prepared to date and discusses aspects of their chirality, including their pictorial and written descriptors

Lanthanoid tetrazole coordination complexes

While tetrazole derivatives are well established as anionic ligands for d-block elements, there is a growing interest in lanthanoid complexes of these compounds. Diverse structural chemistry results from the presence of four potential donor N atoms, and the conjugated nature of the heterocycle can impact on the photophysical properties of the complexes. This review examines the range of structurally characterised lanthanoid–tetrazolato complexes, focussing on the structural features of the ligand that impact on the tendency to interact with the first or second coordination spheres

Synthesis and structural studies of a lanthanide complex of a calix[4]arene tris-amide

The coordination chemistry of amide-substituted calixarenes is reviewed. The synthesis of a gadolinium complex of a trisamide calix[4]arene is described, involving the reaction of 5,11,17,23-tetra-tert-butyl-24-hydroxy-26,27,28-tris(diethylcarbamoylmethoxy) calix[4]arene (L) with gadolinium picrate dodecahydrate. Structural studies demonstrated that the complex can be formulated as [(pic-O)Gd{(L H)(EtOH)}](pic)2 EtOH

Rod-shaped barium sulfate particles from a completely inorganic system

Rod-shaped barium sulfate particles can be formed from purely inorganic systems at 75 1C and theseparticles are single crystals elongated in the c-axis. This c-axis growth promotion relative to the othercrystal faces is absent when the cation impurities are absent suggesting a specific interaction of thecations with the growing crystal. Attempts have been made to determine the cause of this c-axisgrowth promotion, but no one mechanism appears to adequately explain this effect and it may be dueto a combination of different impacts. The same cations do not induce rod-shaped particles at 25 1C,thus suggesting an important role of kinetics in the crystallization of these particles. Finally, previousreports suggesting that the formation of rod-like particles is due to the presence of an organic additivemay be incorrect as sufficient sodium ions may have been present to give these particles even in their absence