Crystal powders

Water-Soluble Trivalent Chromium Compounds. Most water-soluble Cr(III) compounds are produced from the reduction of sodium dichromate or chromic acid solutions. This route is less expensive than dissolving pure chromium metal, it uses high quaHty raw materials that are readily available, and there is more processing fiexibiHty. Finished products from this manufacturing method are marketed as crystals, powders, and Hquid concentrates. 

Physicochemical Properties White crystal powder, granular or tablets, with stimulant smell of Hypochloric Acid, slightly soluble in water, easily soluble in Acetone. ... 

Physical state Solid Solid Crystalline powder Hexagonal crystals powder... 

Physical state Crystals Solid Cubic or metallic crystals powder Oily liquid... 

Cleaver, J. A. S., and Ghadiri, M., Impact Attrition of Sodium Carbonate Monohydrate Crystals, Powder Tech., 76 15 (1993)... 

It is usually injected but can be evaporated to crystals, powdered, and smoked, snorted, or swallowed. Marijuana cigarettes can be soaked in ketamine solution. 

Sample single crystal single crystal powder single crystal powder... 

Physical Form. Black crystal powder that varies in particle size and degree of aggregation... 

The claims of exclusive formation of rac-stilbene dichloride upon gas-solid addition of chlorine to frans-stilbene (103) [71] and of meso-stilbene dibromide in the gas-solid addition of bromine to trans- or czs-stilbene [54] could not be verified. Scheme 12 shows the results of more detailed studies indicating the mesolrac ratios on the solid-state chlorination and bromination of trflns-stilbene (103) and some variations when the crystal size was changed [58, 60-61]. There is a risk of partial transient liquefaction if the chlorine is added too rapidly, due to initially heavy reaction. But even at the start with a stoichiometric amount of chlorine at 0.1 bar and 0 °C, a persistent product layer forms on the unground crystal powder of 103 that cannot be disintegrated by the ultrasound of a cleaning bath at 20 °C for 60 h (only 7% conversion with mesolrac ratio of 11 89 under these conditions) [22]. It is therefore unavoidable to mill the crystals of 103 to sizes <1 pm in order to overcome these rare diffi-... 

Chang YS, Chang YH, Chen IG, Chen GJ, Chai YL (2002) Synthesis and characterization of zinc titanate nano-crystal powders by sol-gel technique. J Cryst Growth 243 319-326... 

White crystal, powder or flake highly hygroscopic the compound and its solutions absorb moisture from the air at various rates depending on calcium chloride concentrations, relative humidity and vapor pressure of water in the air, temperature, surface area of exposed material, and the rate of air circulation at 40% and 95% relative humidity and 25°C, one gram anhydrous calcium chloride may absorb about 1.4 g and 17 g water, respectively. (Shearer, W. L. 1978. In Kirk-Othmer Encyclopedia of Chemical Technology, 3rd ed., vol. 4, pp. 432-6. New York Wiley Interscience) density 2.15, 2.24, 1.85, 1.83 and 1.71 g/cm for the anhydrous salt and its mono-, di-, tetra- and hexahy-drates, respectively anhydrous salts melts at 772°C, while the mono-, di-, tetra- and hexahydrates decompose at 260°, 175°, 45.5° and 30°C, respectively the anhydrous salt vaporizes at 1,935°C highly soluble in water, moderate to high solubility in alcohol. 

The point symmetry of the octahedral sites in the spinel-structure is Dsd- While the octahedra are perfect for an oxygen parameter u of 3/8, they are compressed along a threefold axis for u < 3/8, and expanded for u > 3/8. In the case of MgCr204 ( a0,385) and MgAl204 (21 = 0,387) ( normal spinels with Mg + in tetrahedral and Cr +, Al + in octahedral sites), the expansion is of the magnitude of about 4 to 5%. The corresponding splitting effects of the second absorption band in the remission spectra of the mixed-crystal powders (Mg)( > (Cr jAL-x) O4 (13) are about... 

For cubic, tetragonal, hexagonal, and trigonal crystals, powder photographs alone may beuised. The same method may be used for crystals of orthorhombic or even lower symmetry, provided that the indices of the reflections at large angles can be found. 

When a large crystal of cyclonite is added to the diphenylamine reagent, a blue color appears slowly on the surface of the crystal. Powdered cyclonite gives within a few seconds a blue color which rapidly becomes more intense. If cinnamic acid is dissolved in concentrated sulfuric acid, and if finely powdered cyclonite is added while the mixture is stirred, gas comes off at a moderate rate, and the mixture, after standing over night and drowning, gives a precipitate which contains a certain amount of p-nitro-cinnamic acid. 

Not long after the discovery of the stimulated Raman effect in liquids 63> it was also detected in single crystals 64), namely diamond, calcite, and a-sulfur. Only much later could it be shown that the effect can also be observed in crystal powders 651. The stimulated Raman effect 99 > is excited by giant-pulse lasers with a power of several MW. The strongest Raman lines of a substance are amplified until their intensity is of the same order of magnitude as that of the exciting line furthermore second, third, etc. Stokes lines of the fundamentals in question are observed with twice, thrice, etc. the frequency shift. 

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