CrystEngComm Blog

This hedgehog is actually a barite crystal, grown for 48 hours at pH 12.5 in hydrogen peroxide

This month’s crystal clear looks decidedly like a hedgehog!

In fact this is a BaSO₄ particle grown using H₂O₂ to control particle morphology. Published in Issue 16 of CrystEngComm the paper describes the growth of BaSO₄ crystals and proposes an interesting growth mechanism via selective adsorption of intermediates HO₂^–, O₂^2- and O₂, generated from the decomposition of hydrogen peroxide during the reaction.

The team from the Institute of Chemistry, Chinese Academy of Sciences were looking to control the morphology of barite without affecting crystal purity. Barite is a material with a wide range of applications, the largest being in drilling fluids (used during oil and gas exploration) and also as a paint and plastic additive as well as application in medicine.

By changing the concentration of H₂O₂ and varying reaction pH the team were able to control crystal morphology. Download the article for free to find out how the team achieved the shape control and see their SEM images revealing the growth of the structures.

Hydrogen peroxide triggered morphological evolution of barium sulfate crystals under basic conditions
Xiao-Hui Zhang, Feng-Wen Yan, Cun-Yue Guo, Feng-Bo Li, Zhi-Jun Huang and Guo-Qing Yuan
CrystEngComm, 2012, 14, 5267-5273

An image taken through an optical microscope of L-arginine acetate grown using a 'Metal-Assisted and Microwave-Accelerated Evaporative Crystallization’ process.

The beautiful image in this month’s crystal clear isn’t actually a crystal cavern. It is crystals of L-arginine acetate grown using a new crystallisation technique. The crystals are of particular interest in non-linear optics given their second harmonic generation properties.

The Aslan Research Group have developed a new crystallisation method to grow L-arginine acetate crystals much faster than the previously reported cooling/evaporation method. The ‘Metal-Assisted and Microwave-Accelerated Evaporative Crystallization’ process uses silver island films and low power microwave heating to grow the crystals quickly. The team also investigated functionalising the metal nucleation surface to see if this enhanced crystal growth. 

The image shown here is of the crystals created using bare silver island films and microwaves, the rest of the teams results, including full details of their growth process can be found in Issue 14 of CrystEngComm. 

Rapid crystallization of L-arginine acetate on engineered surfaces using metal-assisted and microwave-accelerated evaporative crystallization
Melissa A. Pinard, Tsehai A. J. Grell, Danielle Pettis, Muzaffer Mohammed and Kadir Aslan

A titanium microsphere, used as the starting material to make hollow whisker balls

With Euro 2012 now well under away this month’s crystal clear couldn’t be more apt – a crystal soccer ball. The paper, from Issue 12 of CrystEngComm, reports the generation of highly crystalline hollow whisker balls.

Using the KCl flux cooling method, the team were able to grow highly crystalline K₂Ti₆O₁₃ whiskers from the centres of titanium microspheres. The ultra-long whiskers grew on a TiO₂ layer, leaving the centre of the sphere hollow and creating a bi-layer hollow whisker ball structure.

The team also used Ti powders as a starting material for the flux process and found this produced significantly different structures, for more details of the teams procedure and some remarkable images of their unique balls, download their article below for free.

Growth of ultralong potassium titanate whiskers by the KCl flux method with metallic titanium materials
Sayaka Suzuki, Katsuya Teshima, Mizuho Kiyohara, Hideya Kamikawa, Kunio Yubuta, Toetsu Shishido and Shuji Oishi
CrystEngComm, 2012,14, 4176-4180
DOI: 10.1039/C2CE00010E