CONTRIBUTION TO THE STUDY OF THE PRECIPITATION OF CHROMATES

1938 ◽  
Vol 16b (2) ◽  
pp. 37-45 ◽  
Author(s):  
P. E. Pelletier ◽  
L. Cloutier ◽  
Paul E. Gagnon
Keyword(s):  
Room Temperature ◽  
Chromium Trioxide ◽  
Potassium Chromate ◽  
Salt Solutions ◽  
Copper Salts ◽  
Metallic Salt

A study was made of the precipitation of the chromates of copper, cadmium, cobalt, zinc, and iron at room temperature. The concentration of the reacting metallic salt solutions was kept constant, and that of the potassium chromate solutions was varied regularly. Solutions were mixed in less than one-tenth of a second, and the rate of mixing was accurately determined. The ratio of oxide to chromium trioxide was found by analysis for chromium trioxide and the metal on the same portion of the precipitate. If the ratio remained constant with varying concentrations of reactants, a definite compound was indicated. The composition of the precipitates obtained with copper salts approached that of the normal chromate. Cadmium and cobaltous salts always gave normal chromates. Zinc and ferric salts yielded only basic mixtures.

Temperature Variation of Principal Moments of Some Polyatomic Crystals

1973 ◽  
Vol 28 (1-2) ◽  
pp. 23-25 ◽  
Author(s):  
O. P. Singhal
Keyword(s):  
Solid State ◽  
Temperature Coefficient ◽  
Single Crystals ◽  
Air Temperature ◽  
Entire Range ◽  
Room Temperature ◽  
Small Variation ◽  
Potassium Chromate ◽  
Absorption Frequency ◽  
Ammonium Dichromate

Principal moments of some of the polyatomic single crystals such as ammonium dichromate, ammonium chromate, potassium chromate and potassium permanganate have been determined from room temperature down to liquid air temperature. These have been found to decrease with the decrease of temperature. This variation is smaller in magnitude. It has been observed that the temperature coefficient of the principal moments has almost the same value over the entire range of temperature. This small variation of paramagnetism has been attributed to the variation of absorption frequency in solid state.

Binuclear copper(II) complexes of the tetradentate ligand 1,4-di(2′-pyridyl)aminophthalazine: some novel five-coordinate derivatives

1969 ◽  
Vol 47 (22) ◽  
pp. 4141-4152 ◽  
Author(s):  
L. K. Thompson ◽  
V. T. Chacko ◽  
J. A. Elvidge ◽  
A. B. P. Lever ◽  
R. V. Parish
Keyword(s):  
Room Temperature ◽  
Principal Series ◽  
Magnetic Data ◽  
Binuclear Copper ◽  
Neutral Form ◽  
Deprotonated Form ◽  
Copper Salts ◽  
X Ray ◽  
Anionic Ligand ◽  
Aromatic Carboxylate

Reaction of the title ligand (L) with copper salts leads to the formation of three principal series of compounds, LCu2X3(OH)•H2O (X = Cl, Br), LCu2(RCO2)3, and LCu2(RCO2)4, where RCO2 represents various aliphatic and aromatic carboxylate species. Magnetic data, electronic spectroscopic data both at room temperature and at −196 °C, infrared spectra, and microanalytical data are correlated to reveal that these complexes contain a binuclear copper-copper system in which the copper atoms are 5-coordinate and square pyramidal. Brief details are presented of an X-ray structural analysis of the chloride complex confirming the structure proposed.The ligand forms complexes both in its neutral form and in an anionic deprotonated form. The ultraviolet spectra of the complexes distinguish these modes of bonding. The electronic spectra are discussed in terms of the 5-coordinate square pyramidal copper chromophore deemed to be present. In the complex L2Cu, the copper atom has a trigonally distorted 6-coordinate environment with tridentate anionic ligand.

Strength of Neoprene Compounds and the Effect of Salt Solutions

1983 ◽  
Vol 56 (4) ◽  
pp. 845-852 ◽  
Author(s):  
A. K. Bhowmick ◽  
A. N. Gent
Keyword(s):  
Tensile Strength ◽  
Lower Limit ◽  
Low Temperatures ◽  
Environmental Effect ◽  
Room Temperature ◽  
Characteristic Temperature ◽  
Salt Solutions ◽  
A Value ◽  
Fecl3 Solution ◽  
Tear Propagation

Abstract Soft CR vulcanizates resemble NR vulcanizates in many ways. Their tensile strength is high at low temperatures and drops sharply at a characteristic temperature to a value of about 1–1.5 MPa. Their tear resistance decreases smoothly as the temperature is raised and does not reach a lower limit, even at temperatures as high as 150°C. However, they show continuous tear propagation at room temperature under relatively large tear forces, whereas NR materials do not. This difference must reflect different strengths of the crystallites formed at the tear tip, those in CR being significantly weaker. Also, a specific environmental effect is noted: When immersed in solutions of FeCl3, the CR materials show more rapid tearing, and they tear at significantly lower forces than in water or in NaCl solutions (or in air). Although they swell continuously in water and in salt solutions, the rate of swelling seems far too low to account for the weakening observed. Moreover, the swelling is greater in water, whereas the weakening is specific to FeCl3 solution. It is attributed to a chemical reaction between FeCl3 and the CR molecule.

Densities and Viscosities of Chromium Trioxide + Potassium Chromate + Potassium Dichromate + Water from (298.15 to 333.15) K

2008 ◽  
Vol 53 (3) ◽  
pp. 648-653 ◽  
Author(s):  
Ji-yan Wang ◽  
Fu-an Wang ◽  
Peng Zhang ◽  
Cheng-wei Li ◽  
Bao-zeng Ren
Keyword(s):  
Chromium Trioxide ◽  
Potassium Dichromate ◽  
Potassium Chromate

Synthesis of Nanophase Noble Metal Systems Utilizing Porous Silicon

1996 ◽  
Vol 457 ◽  
Author(s):  
I. Coulthard ◽  
T. K. Sham
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Porous Silicon ◽  
Noble Metal ◽  
Photoelectron Spectroscopy ◽  
Room Temperature ◽  
Visible Range ◽  
X Ray ◽  
Metallic Salt ◽  
Scanning Electron

ABSTRACTApart from its well known ability to luminesce very intensely at room temperature in the visible range, porous silicon is also an effective reducing agent. We report the formation of several noble metal (Pd, Ag, Au, Pt) nanostructures by reductive dispersion of metal ions from aqueous solutions onto the surface of porous silicon. The nanophase systems produced by reductive deposition vary with the element deposited and the metallic salt utilized in the process. The resulting nanophase systems were studied using a variety of techniques including: scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), and spectroscopie methods using synchrotron radiation.

scholarly journals STUDIES IN AGGLUTINATION

1924 ◽  
Vol 39 (2) ◽  
pp. 245-263 ◽  
Author(s):  
Gerald S. Shibley
Keyword(s):  
Room Temperature ◽  
Cohesive Force ◽  
Salt Solutions

1. The spontaneous agglutination of streptococci has been studied. 2. This spontaneous agglutination would seem to be caused by the presence of a bacterial cohesive force higher than that usually found when bacteria are suspended in salt solutions of the concentration commonly employed as electrolyte in specific agglutination reactions. 3. Many granular autoagglutinating strains of streptococcus may be made diffuse by growth at room temperature (17–23°C.) and then lose their tendency to agglutinate spontaneously. 4. All factors that reduce cohesive force or that make the repelling force relatively greater than the cohesive force make for stable suspensions. 5. Methods for management of the specific agglutination of refractory autoagglutinating strains of streptococci have been presented.

Room Temperature Phase-Selective Synthesis of Metastable Lead Chromium Oxides

1997 ◽  
Vol 495 ◽  
Author(s):  
Kenneth M. Doxsee ◽  
Meehae Jang
Keyword(s):  
Lead Oxide ◽  
Room Temperature ◽  
Potassium Chromate ◽  
Temperature Phase ◽  
Selective Synthesis ◽  
Tertiary Amines ◽  
Metathesis Reaction ◽  
Soluble Complex ◽  
Monoclinic Modification ◽  
Rich Phase

ABSTRACTThe salt metathesis reaction between lead(II) salts and potassium chromate in methanolic solution, mediated by the formation of a soluble complex of potassium chromate with a cyclic polyether, affords orthorhombic PbCrO4 rather than the monoclinic modification formed in aqueous solution. When the aqueous metathesis reaction is carried out in the presence of tertiary amines, a lead oxide-rich phase, PbO•PbCrO4 (Pb2CrO5), is selectively formed.

scholarly journals A novel one-step synthesis of Ce/Mn/Fe mixed metal oxide nanocomposites for oxidative removal of hydrogen sulfide at room temperature

RSC Advances ◽  
2021 ◽  
Vol 11 (43) ◽  
pp. 26739-26749
Author(s):  
Nishesh Kumar Gupta ◽  
Jiyeol Bae ◽  
Kwang Soo Kim
Keyword(s):  
Hydrogen Sulfide ◽  
Metal Oxide ◽  
Molten Salt ◽  
Room Temperature ◽  
Mixed Metal Oxide ◽  
Salt Solutions ◽  
Mixed Metal ◽  
Oxidative Removal ◽  
One Step

In this study, CeO2/Fe2O3, CeO2/Mn2O3, and CeO2/Mn2O3/Fe2O3 nanocomposites were synthesized by the calcination of molten salt solutions.

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