Infrared Spectroscopic and Thermal Studies of Gel Grown Spherulitic Crystals of Iron Tartrate

Growth of spherulitic crystals of iron tartrate by controlled diffusion in sodium metasilicate gels has been described. Infrared spectroscopic, thermogravimetric and elemental analysis have been conducted to characterize the crystals. The results are interpreted and explained.     

Dendritic Growth of Ammonium Tartrate Single Crystals in Silica Gel

Dendritic growth of Ammonium tartrate single crystals in silica gel at 30 °C is reported. Main stem parallel to the ‘C’ axis is observed. Dendritic growth in initial and final stages with its surface structures are illustrated and described. Growth features are correlated to the growing conditions and reacting components.     

Growth of Potassium Sulphate Crystals by Silica Gel Technique

Single and transparent crystals of potassium sulphate up to 30 × 3 × 3 mm in size have been grown by silica gel technique, using various methods (two-layers three-layers and hybrid gel technique) which are described. The effects of the three differents alcohols (used as top solutions) upon the quality and nucleation of crystals are also reported. The “growth and equilibrium” morphologies and microstructures of the habit faces are discussed.     

Growth,Structural and Microtopographical Studies of Calcium Iodate,Monohydrate Crystals Grown in Silica Gel

Single crystals of calcium iodate, monohydrate [Ca(IO₃)₂, H₂O] have been grown by gel technique. Prismatic, prismatic pyramidal, needle shaped and hopper crystals were obtained. These crystals were also grown by doping impurities such as copper and iron. Kinetics of growth parameters was investigated. Structural analysis was carried out by using X‐ray powder diffraction method. Microtopographical study of the habit faces, such as prismatic and pyramidal, of as grown crystals was carried out. Some surface structures are reported. These crystals were etched by various etchants and appropriate etchant is reported.     

Growth of Doped Potassium Perchlorate Single Crystals in Silica Gel and Their Characterization

Chemical reaction method was employed to grow doped potassium perchlorate single crystals in silica gel. Dopants used were potassium permanganate and potassium dichromate and the dopant levels were 500 and 1000 ppm. FT-IR spectral analysis, etching study and microhardness measurements were carried out for these crystals.     

Growth and Characterisation of Pure and Nickel-doped Strontium Tartrate Tetrahydrate Single Crystals

Strontium tartrate tetrahydrate single crystals doped with nickel have been grown in silica gel. The grown crystals have been characterized by X-ray, atomic absorption spectroscopy (AAS), thermogravimetric analysis (TGA), and etching technique.     

Growth and Kinetic Measurements of Triglycine Sulphate Crystals

Synthesis and two-step recrystallisation have been used to produce TGS basic substance. Kinetic measurements have been performed for (110)-type face on a large scale of supersaturations up to about 3%. Evidences of impurity influence for small supersaturation and the “coverage” effect has been estimated.     

Growth of Large Needles and Single Crystals of PbCl2 and PbBr2 in Silica Gel. An Improvement of the New Gel Technique

In growing crystals by the new gel technique a principal difficulty may arise in that it may be difficult or at times impossible to choose two nutrients that may react to produce the desired crystals. With some crystals, the pair of nutrients that may appear practically most suitable, may not react at all or the rate of reaction may be exceedingly small. Further work on the new gel technique has now led to an improvement of the technique by which it is feasible to impart activity to nutrients which are normally non-reactive or to enhance the reactivity of generally less reactive nutrients. Large needles of PbCl₂ and PbBr₂ have been grown in silica gel by this improvement of the new gel technique. The interesting phenomenon of transformation of needles of PbCl₂ and PbBr₂ into single crystals has been investigate and the various aspects of growth systematically studied.     

FT-IR and Raman Spectra of Ammonium Hydrogen Tartrate and Potassium Hydrogen Tartrate Crystals

FT-IR and Raman spectra of ammonium hydrogen tartrate [NH₄HC₄H₄O₆] and potassium hydrogen tartrate [KHC₄H₄O₆] have been measured. Vibrational assignments have been made for both the internal and external vibrations. Because of the free rotation of the NH₄⁺ ion, it forms only weak hydrogen bonds with the oxygen atom.     

稀土掺杂钨酸钆钠激光晶体的生长及性能研究

采用提拉法生长出纯的和Nd3+、Tm3+、Ho3+、Dy3+、Pr3+掺杂的大尺寸优质NaGd(WO4)2 晶体.测定了晶体沿(001)和(100)方向的热膨胀系数.测定了晶体的折射率,得到了折射率的色散方程.测量了NaGd(WO4)2 晶体的拉曼光谱,对晶体的振动性能进行研究.对稀土离子掺杂的NaGd(WO4)2 晶体进行了一系列的光谱性质研究,并进行了Judd-Ofelt理论计算.Nd3+:NaGd(WO4)2和Tm3+:NaGd(WO4)2晶体在800 nm附近吸收峰的半高宽和吸收截面较大,有利于LD泵浦.测定了不同能级的荧光寿命,发现Nd3+:NaGd(WO4)2 晶体具有较高的荧光量子效率.采用氙灯闪光灯作为泵浦源,研究了Nd3+:NaGd(WO4)2晶体1060 nm的激光特性.     

Growth of Single Crystals of Calcium Sulfite in Silica Gels

The paper reports on the growth of single crystals of calcium sulfite, CaSO₃ 0.5 H₂O, by reaction of aqueous solutions of CaCl₂ and Na₂SO₃ in silica gels. Na₂SO₃ incorporated gels give spherulites whereas CaCl₂ incorporated gels give transparent single crystals. The morphology of the crystals depends on the region of the gel and the type of reactant incorporated into the gel-forming solution. Initially formed precipitate and dendrites are converted into good quality single crystals by dissolution and recrystallization processes.     

Dendritic Growth of Potassium Dihydrogen Phosphate Crystals in Silica Gels

Dendritic growth of potassium dihydrogen phosphate (KDP) crystals in silica gels at room temperature is reported. Branching along directions perpendicular to the arms and dendrites growing in mutually perpendicular 〈100〉 and 〈010〉 directions are illustrated. Initial stages and surface of a dendrite are illustrated and described. Also explained are the crystallites growing on the dendrite which finally lead to the formation of platelets.