Quinones are widely found in nature, used in chemistry and medicine, and are just beginning to gain importance in materials engineering. In order to harvest their potential as an ordered or highly crystalline solid, their crystal formation processes need to be well investigated and controlled. We chose 1,4-anthraquinone, a commercially available type of quinone, as a model compound to study its...

calcium dichloride tetra urea was prepared by the reaction of calcium chloride with urea in aqueous solution. the crystals are monoclinic, a= 7.633, b= 12.45 1, c= 8.118 ?,? = 113.17, z = 4, space group p 2,/a. the crystal structure was determined by single crystal x-ray methods and refined to r= 0.041. the calcium atoms are coordinated to four oxygen atoms of urea and to two chloride ions. the...

Hgl -,Cd,Te and Cdl -,Zn,Te single crystals were grown by the travelling heater method (THM), applying two different techniques of artificially stirring the solution zone. Accelerated crucible rotation (ACRT) was used in a vertical growth arrangement and compared a technique with constant rotation around the horizontal axis of the ampoule. The dominant hydrodynamic mechanisms of both methods ar...

The experimental data concerning growth kinetics of vitamin C (L(+)-ascorbic acid, LAA) crystals in a seeded and cooling batch mass crystallization process realized in a four–compound: L(+)-ascorbic acid–methanol–ethanol–water system are reported. Influences of initial composition of solution and its linear cooling rate on “average, effective” values of crystal linear growth rate were examined....

To study the establishment of homochirality observed in the crystal growth experiment of chiral molecules from a solution under grinding, we extend the lattice gas model of crystal growth as follows. A lattice site can be occupied by a chiral molecule in R or S form, or can be empty. Molecules form homoclusters by nearest neighbor bonds. They change their chirality if they are isolated monomers...

Details of crystal growth in the calcitostracum of Crassostrea virginica have been studied with the purpose of analyzing the formation of the overlapping rows of oriented tabular crystals characteristic of this part of the shell. Crystal elongation, orientation, and dendritic growth suggest the presence of strong concentration gradients in a thin layer of solution in which crystallization occur...

The concentration fluxes in the vicinity of protein crystals growing from its aqueous solution has been investigated using laser based interferometric technique. A Mach-Zehnder interferometer has employed for the experimentation. Lysozyme (Hen-Egg-White) has used as the protein, where sodium chloride (Nacl) is used as the precipitant and Sodium acetate (CH3COONa) as buffer. A test cell with dim...