Is Dual Morphology of Rock‐Salt Crystals Possible with a Single Additive? The Answer Is Yes, with Barbituric Acid

Abstract

Crystal face lift: barbituric acid is shown to be a new crystal-habit modifier for sodium chloride crystals. Two morphologies of salt crystals can be prepared separately with this new additive. It is of the few additives able to induce rhombic dodecahedron crystals for NaCl, and is required only a trace of amount, unlike other additives, such as glycine.

Antifreeze Protein‐Induced Selective Crystallization of a New Thermodynamically and Kinetically Less Preferred Molecular Crystal

“…It is known that crystal shape changes can be due to either the habit modification of the same crystalline form or more frequently the formation of a new crystalline form. [1a, 2] In this study, the formation of the new, less thermodynamically and kinetically preferred m5U dihydrate crystals was able to be induced by DAFP-1, demonstrating the latter case.…”

“…[1] For instance, changes in the size and shape of crystals of pharmaceutical compounds can impact on their bioavailability, chemical stability, and production efficiency of the drugs. Traditional methods to control crystallization usually include the alterations of temperature, solvent, supersaturation, and seeding conditions.…”

“…Although tremendous effort has been devoted to understanding the crystallization process and selective crystallization, the crystallization control process remains largely trial-and-error, experiencing substantial difficulties in exclusive production of the desired forms as well as the production of both thermodynamically and kinetically less favored forms. [1a, 5] Moreover, much less progress has been made in additive-controlled organic crystallization than in additive-controlled inorganic crystallization and the selective production of organic single crystals with defined crystal phase and morphology is hard to achieve. [10] …”

Continuous Production of Water‐Soluble Nanocrystals through Anti‐Solvent Precipitation in a Fluidic Device

“…A variety of additives, including glycine, formamide, cysteine, creatinine, and cadmium chloride, can be added to control the morphology of the resultant NaCl crystals. Shapes such as cubic, octahedral, and dodecahedral have all been achieved, but the crystals obtained using this method inevitably have a large particle size, typically on the microscale . To reduce the particle size down to the nanoscale, techniques such as spray drying, vapor shock cooling, and rapid water evaporation from aerosols have been utilized.…”

“…Shapes such as cubic, octahedral, and dodecahedral have all been achieved, but the crystals obtained using this method inevitably have a large particle size, typically on the microscale. [10][11][12] To reduce the particle size down to the nanoscale, techniques such as spray drying, vapor shock cooling, and rapid water evaporation from aerosols have been utilized. However, the products are typically characterized by a broad distribution in size.…”