Sodium Metasilicate Gel Research Articles

Synthesis and characterization of ferroelectric magnesium hydrogen phosphate single crystals

AbstractFerroelectric Magnesium Hydrogen Phosphate MgHPO4 (MHP) single crystals are grown by slow diffusion of magnesium chloride in sodium metasilicate gels impregnated with orthophosphoric acid. Bright and transparent prismatic, tabular, and isometric habit MHP crystals upto 3 × 2 × 1 mm3 are obtained. Results of chemical, X‐ray diffraction, EDAX, microhardness and magnetic analysis are reported. The average etch pit density is determined by chemical etching to be 7 × 103 cm−2. Microtopographic investigations revealed the mechanism of crystal growth.

Growth and properties of ferroelectric lead hydrogen phosphate and lead nitrate phosphate single crystals

Ferroelectric lead hydrogen phosphate (LHP) and lead nitrate phosphate (LNP) single crystals are grown together by slow diffusion of lead nitrate by sodium metasilicate gels impregnated with orthophosphoric acid. A brief description of the material preparation, growth procedure and crystal nucleation, is given. Bright and transparent prismatic LHP crystals up to 7 × 4 × 3 mm 3 and LNP crystals up to 12 × 6 × 3 mm 3 in size are obtained. It is observed that the growth rate of the LNP crystals is faster than that of the LHP crystals. Results obtained on characterization of these two crystals chemical, and on analysis, X-ray diffraction, EDAX, etc. are reported. The microhardness and Young modulus of these crystals are determined. The average density of dislocations has been determined by employing the chemical etching technique and found to be 3 × 10 2 cm -2 in LHP and 7 × 10 2 cm -2 in LNP crystals. The implications are discussed.

Preparation of HUO2PO4·4H2O single crystals from gel

Abstract Single crystals of HUO2PO4·4H2O were grown by diffusing a solution of UO2(NO3)2·6H2O into a sodium metasilicate gel set with phosphoric acid. The crystals grew with a tetragonal morphology and had maximum dimensions of 2.0 mm × 2.0 mm × 0.4 mm.

Growth mechanism of Herring-Bone and Hour-glass synthetic gypsum

Synthetic gypsum crystals are grown from sodium meta silicate gel when 1M calcium chloride solution diffuses into the gel imbedded with 1M amonium sulphate solution. Acicular-shaped crystals of Herring-Bone structure are observed. When methanol was added to the gel medium, tabular crystals revealing Hour-glass structure are rarely observed. In the presence of methanol the silicate particles are inhibited from being incorporated into the crystals as a result of pushing and incorporating mechanisms. Inclusion of silicate particles in traces gives rise to Hour-glass pattern. The implications are discussed.

Dendritic structures in gel grown Gypsum

AbstractSparingly water soluble Calcium Sulphate dihydrate (Gypsum) single crystals are grown by gel method, derived from the highly soluble reactants, Calcium Chloride and ammonium sulphate. By the diffusion of 1M Calcium Chloride solution into Sodium metasilicate gel (Sp.gr: 1.06 gm Cm–3, pH ∼ 7.5), imbedded before setting, with varied amounts of weak acid (acetic acid) and 20 ml of 1M ammonium sulphate solution, dendritic structures are commonly observed in the gel at the interface, at a particular concentration of the acid. The needle shaped tabular crystals are also observed to grow at the greater depths in the gel.Dendrites are studied by optical, X‐ray diffraction and Infra‐red studies. It has been established that the dendrites are Calcium Sulphate dihydrate crystals formed probably due to the influence of soluble impurities (like calcium acetate, in the present case), when the rate of diffusion is fairly high and the twinning mechanism favoured. The implications are discussed.

Growth of single crystals of some complex salts in silica gels

Single crystals of ammonium nickel sulphate, potassium nickel sulphate, ammonium alum and potassium alum are grown in sodium-metasilicate gels. The method of gel preparation and growth procedure are described. Both single diffusion and double diffusion methods are used. Studies on nucleation and characterisation of crystals are also reported. Crystals grown are illustrated.

Surface studies of electrically conducting “CsSn 2I 5”

Single crystals of CsSn 2I 5 have been grown in sodium metasilicate gels and identified by X-ray powder and single-crystal diffraction methods. The CsSn 2I 5 crystals are good electrical conductors and show unusual photochemical behavior. The nature of these properties has been probed with Auger electron spectroscopy. This paper considers the synthesis, chemical characterization, and surface properties of CsSn 2I 5.

Gel growth of single crystals of some rubidium and cesium tin halides

Single crystals of several rubidium and cesium tin halides of up 3 × 3 × 3 mm have been grown in sodium metasilicate gels and identified by X-ray powder and single crystal diffraction methods and by chemical analyses. Several different crystal habits were obtained depending upon the halide used and the stoichiometry of the compound formed. The RbSn 2I 5 and CsSn 2I 5 crystals were light sensitive, and the black crystalline forms were found to be semiconducting.

Observations on the growth of single crystals of lead molybdate from gels

It is reported that PbMoO 4 crystals can be grown in a sodium metasilicate gel media. Crystals with several different habits were obtained. A possible growth mechanism is discussed on the basis of the morphology of these crystals.

Growth of BaMoO4 and BaCO3 crystals in silica gel media

Barium molybdate, BaMoO4, and barium carbonate, BaCO3, crystals have been grown in sodium metasilicate gels. The influence of concentration of reactant solutions and pH of gels on the nucleation and growth, and on the penetration depth of the growth front of BaMoO4 crystals in the test tubes were primarily studied. Combinations of pH 6 gel mixture with the 0.4 m and 0.6 m supernatant BaCl2 and Na2MoO4 solutions resulted in the best size of crystals, inter-crystalline separation and clarity of the gel media. Two best test tube experimental combinations of hybrid growth were repeated in the U-shaped glass tubes to obtain further information. Depending on the growth sites in the tubes, different morphologies of the crystals were observed. The bulk morphologies of these crystals were studied by scanning electron microscopy. Growth of BaCO3 crystals was performed only as exploratory work in the test tubes.