Effect of urea additives on CuSO4·5H2O crystal habit: an experimental and theoretical study

Oblique hexagonal prism copper(ii) sulfate pentahydrate crystal was formed due to the preferential adsorption of urea molecules on specific faces.

Tailoring NiO Nanostructured Arrays by Sulfate Anions for Sodium-Ion Batteries

In this contribution, a novel sulfate-ion-controlled synthesis is developed to fabricate freestanding nickel hydroxide nanoarrays on Ni substrate. As an inorganic morphology-controlled agent, SO₄^2- ions play a critical role in controlling the crystal growth and the nanoarray morphologies, by modulating the growth rate of adsorbed crystal facets or inserting into the metal hydroxide interlayers. By controlling the SO₄^2- concentration, the nanostructured arrays are tailored from one-dimensional (1D) Ni(SO₄ )_0.3 (OH)_1.4 nanobelt arrays to hierarchical β-Ni(OH)₂ nanosheet arrays. With further graphene oxide modification and postheat treatment, the obtained NiO/graphene hybrid nanoarrays show great potential for high-performance sodium-ion batteries, which exhibit a cyclability of 380 mAh g^-1 after undergoing 100 cycles at 0.5 C and reach a rate capability of 335 mA h g^-1 at 10 C.

Computational predictions turning the isomers of alanine to generate distinct morphs of free-flowing salt crystals

The morphology of salt crystals has been an active area of research for decades and remains largely empirical. This study reveals the computational modeling guides to arrive at the correct answer, even for complex problems, such as the morphology of salt crystals with additives. There is no report on the two different morphologies of rock-salt crystals with two isomers of a single additive. Alanine isomers (α- and β-) can induce octahedron and rhombic dodecahedron morphologies in salt crystals. The computational study demonstrated that α-alanine preferentially interacts with {111} and β-alanine with {110} planes to yield such morphologies. The change in morphology with alanine can greatly influence the problem of the free-flowing issue of salt crystals.

DNA action on the growth and habit modification of NaCl crystals

{100} hopper-like NaCl crystals were prepared upon the action of DNA by the solvent evaporation method.

Revealing the parameters to design the habit modifiers for rock-salt crystals: empirical to rational approach

Morphology of rock-salt crystals can be influenced by internal and external factors like temperature, super saturations, solvent, and impurities. Many impurities and additives have been reported to date for the habit modification of common salt; however, the selection of such impurities is largely empirical. The partition coefficient or log P, which is a measure of hydrophobic hydrophilic property of a material, very aptly signifies the ability of additives to modulate the morphology of sodium chloride crystals. Application of the partition coefficient of additives led to the discovery of two new habit modifiers (cytosine and DMSO) for rock-salt crystals. The predicted results have been verified by experimental studies. Furthermore, the known habit modifiers and also the nonhabit modifiers for sodium chloride crystals corroborate the importance of this parameter to define the morphology of salt crystals. This study is of fundamental importance, which otherwise was rather empirical for the last two centuries.

Antifreeze protein-induced selective crystallization of a new thermodynamically and kinetically less preferred molecular crystal

The formation of a new, dihydrate crystalline form of 5-methyluridine (m(5)U) was selectively induced by a protein additive, antifreeze protein (AFP) in a highly efficient manner (in 10(-6) molar scale, whereas known kinetic additives need 0.1 molar scale). The hemihydrate form (form I, the only previously known crystalline form of m(5)U) and the dihydrate form of m(5)U (form II) obtained herein were characterized using X-ray crystallography and differential scanning calorimetry (DSC). Compared to form I, remarkably, form II is thermodynamically and kinetically less preferred. The presence of AFP can selectively inhibit the appearance of form I and hence allows the growth of form II, the pure form of which cannot grow directly from m(5) U supersaturated solutions under the same conditions. An explanation supported by both experimental and theoretical results is provided for the AFP-induced selection process. Implications on AFP-induced ice shape changes are also discussed. Control of crystallization from supersaturated solutions is of great interest in both fundamental research and practical applications in fields like chemistry, pharmacology and materials science. These findings suggest that crystallization processes with AFPs could be valuable for selective growth of hydrates and polymorphs of important pharmaceutical compounds.