the crystals of [ws (cuncs) ] anion have been isolated from ch ,ci solution and examined by x-ray structural analysis as well as by ir spectroscopy. the unit cell is monoclinic with a= 14.3796(13), b= 18.039(1 i), c= 22.5956(23)& p= 96.053(8)', space group p2,/n (14), z= 4. the crystal structure was refined by the least-squares calculations to a final r-value of 0.0398(rw= 0.0443) for 2777...

The crystal structure of 2,4,6,8,10,12-hexanitro-2,4,6,8,10,12-hexaazaiso-wurtzitane (CL-20) p-xylene solvate, and the solvent effects on the crystal faces of CL-20 were studied through a combined experimental and theoretical method. The properties were analyzed by thermogravimetry-differential scanning calorimetry (TG-DSC), Fourier transform infrared spectroscopy (FTIR) and X-ray diffraction (...

Solution crystallization and dissolution are of fundamental importance to science and industry alike and are key processes in the production of many pharmaceutical products, special chemicals, and so forth. The ability to predict crystal growth and dissolution rates from theory and simulation alone would be of a great benefit to science and industry but is greatly hindered by the molecular natu...

Detailed numerical analysis is presented for the effect of spaceship orbital transfer on solution convection during protein crystal growth under microgravity. The results show that the flow and mass transfer during protein crystal growth are unsteady in the process of orbital transfer. For the case of quasi-steady acceleration, the flow is so weak that the effect of flow on concentration field ...

A screening of amorphous, heptahydrate, and tetrahydrate forms disodium guanosine 5′-monophosphate is investigated using an antisolvent crystallization process with the aim to selectively produce each solid form. The concentrations solution are monitored by in situ Raman spectroscopy a calibration tool. Particle sizes particle counts measured elapsed time focal beam reflection measurement. Conc...

This paper reports the growth and spectral properties of Er(3+)-doped and Er(3+)/Yb(3+)-codoped Li(3)Ba(2)La(3)(WO(4))(8) crystals. The Er(3+): Li(3)Ba(2)La(3)(WO(4))(8) crystal with dimensions of 56 mm × 28 mm × 9 mm and Er(3+)/Yb(3+): Li(3)Ba(2)La(3)(WO(4))(8) crystal with dimensions of 52 mm × 24 mm × 8 mm were obtained by the top-seeded solution growth (TSSG) method. Thermal expansion coeff...

Nanostructured Ni2As2O7 semiconductor samples were synthesized by a solid state method among As2O3 and Ni(NO3)2.6H2O raw materials at 650 °C (S1) and 750 °C (S2) as reaction temperatures. The synthesized nanomaterials were characterized by powder X-ray diffraction (PXRD) technique and F...

Thermodynamic calculations were performed to determine the optimal conditions for growth of germanium epitaxial layers from a Ge-Sn solution (system) substrate. The determination was based on change in Gibbs energy values system during crystallization process and size crystal-forming nanoclusters. Based results obtained, we determined obtaining low-dislocation, crystalline perfect liquid tin so...

Abstract. In this paper we present a model for computing thermal stress inside a crystal with facets. Using a systematical perturbation analysis, a semi-analytical thermal stress solution is obtained for constrained directional growth with small lateral heat flux. Our solution can be applied to crystals grown by various growth techniques such as the Czochralski method. The semianalytical nature...

Growth of low energy planes of perfect crystals at low supersaturation requires two-dimensional nucleation. The formation energy of nuclei of i atoms may be written G’( = -ikT In cc+G,(i), where G( is the saturation ratio. An atomistic evaluation of G,, for a simple model, is in good agreement with the classical form G,(i) = iiD’, with a constant edge energy coefficient b’, even for very small ...