Additive Induced Formation of Ultrathin Sodium Chloride Needle Crystals

Abstract

A multitude of ultrathin crystal needles are formed during the evaporation of saturated aqueous NaCl solution droplets in the presence of amide containing additives. The needles are as small as 300 nm wide and 100–1000 μm in length. Heating experiments, X-ray diffraction, and energy dispersive X-ray spectroscopy showed that the needles are cubic sodium chloride crystals with the needle length direction pointing toward [100]. This shape, not expected for the 43̅m point group symmetry of NaCl, has been explained using a model, based on tip formation by initial morphological instability followed by time dependent adsorption of additive molecules blocking the growth of the needle side faces. The latter also suppresses side branch formation, which normally occurs for dendrite growth.

Enhancement of aragonite mineralization with a chelating agent for CO2 storage and utilization at low to moderate temperatures

“…The formation of these acicular particles may be closely related to the drastic increase in crystallite size in the 012 direction. Moreover, GLDA inhibited the caking of aragonite particles, which may imply a lower surface energy of aragonite 28 , 47 . In the presence of GLDA, Ca ions were gradually released from Ca-GLDA complexes for carbonation, and the resulting low Ca 2+ /CO 3 2− ratio was considered to induce aragonite formation 29 .…”

“…However, different chelating agents may have different effects on interfacial energy. Westin and Rasmuson (2005) reported that the inclusion of chelating agents such as EDTA notably increased the interfacial energy 26 , whereas Townsend et al (2018) reported that nitrilotriacetamide (NTAA), methylglycine diacetamide (MGDA), and N,N -dicarboxymethyl glutamic acid (GLDA) decreased the interfacial energy and thus promoted the precipitation of acicular NaCl crystals 28 . On the other hand, the complexation of Ca ions by chelating agents results in a gradual release of these ions during carbonation and, hence, in a low Ca 2+ /CO 3 2− ratio.…”

Tunable NaBH4 Nanostructures Revealing Structure‐Dependent Hydrogen Release

“…[27] Notably, in this case, the growth mode of the NaBH 4 bars may occur along the [100] direction as previously observed in the case of cubic NaCl crystals elongated as needles. [28] The crystal structure of NaBH 4 is isomorphous to NaCl; therefore, the nucleation and growth of NaBH 4 can also be explained based on the studies on NaCl crystals. [28,29] Wang et al [29d] argued that the formation of cubic morphology of NaCl is due to the fast diffusivity of Na þ and Cl À ions and a nondirectional growth in aqueous solutions.…”

Radiolysis-Induced Crystallization of Sodium Chloride in Acetone by Electron Beam Irradiation

“…In aqueous solution, the growth shape of a NaCl crystal is generally rectangular and the direction of the growth of dendrites is generally 〈110〉 or 〈111〉 (Goto et al, 2016). It is commonly observed that the growth shape of NaCl crystals is dependent on the solvent (Stoica et al, 2004) and that the shape of NaCl crystals can be changed by the presence of an organic additive in an aqueous solution of NaCl (Townsend et al, 2018). In our experiments, the dendritic shape of the NaCl crystal was caused by the acetone, possibly due to differences in solvent-surface interactions from those in aqueous solution inducing drastic changes in facial growth rates (Stoica et al, 2004).…”