C:Corrosive;
10026-11-6Relevant articles and documents
Synthesis of BaZrS3 in the presence of excess sulfur
Wang, Yarong,Sato, Nobuaki,Yamada, Kohta,Fujino, Takeo
, p. 214 - 223 (2000)
Synthetic reaction of barium zirconium sulfide, BaZrS3, was studied in a large excess amount of sulfur melt at temperatures of 623-723 K and in the presence of a small amount of excess sulfur at temperatures of 623-823 K, respectively. The results showed that BaZrS3 was formed with high yields by heating at temperatures ranging from 723 to 873 K, if a proper amount of excess sulfur and 10 mole% of BaCl2 were added in the starting materials. The compound could be obtained in almost a single phase with only 2-3 mole% ZrO2 impurity after the 8 min water treatment of the products obtained at 873 K. The modified method studied in this paper, i.e. reaction in the medium temperature range of 723-873 K, was shown to be applicable for synthesizing the mixed sulfides of some kinds including BaZrS3.
Zirconium tetrachloride revisited
Borjas Nevarez, Rosendo,Balasekaran, Samundeeswari Mariappan,Kim, Eunja,Weck, Philippe,Poineau, Frederic
, p. 307 - 311 (2018)
Zirconium tetrachloride, ZrCl 4, is a strategic material with wide-ranging applications. Until now, only one crystallographic study on ZrCl 4 has been reported [Krebs (1970). Z. Anorg. Allg. Chem. 378, 263-272] and that was more than 40 years ago. The compound used for the previous determination was prepared from ZrO 2 and Cl 2 -CCl 4, and single-crystal X-ray diffraction (SCXRD) studies on ZrCl 4 obtained from Zr metal have not yet been reported. In this context, we prepared ZrCl 4 from the reaction of Zr metal and Cl 2 gas in a sealed tube and investigated its structure at 100, 150, 200, 250, and 300 K. At 300 K, the SCXRD analysis indicates that ZrCl 4 crystallizes in the orthorhombic space group Pca2 1 [a = 6.262 (9), b = 7.402 (11), c = 12.039 (17) ?, and V = 558.0 (14) ? 3 ] and consists of infinite zigzag chains of edge-sharing ZrCl 6 octahedra. This chain motif is similar to that observed previously in ZrCl 4, but the structural parameters and space group differ. In the temperature range 100-300 K, no phase transformation was identified, while elongation of intra-chain Zr?Zr [3.950 (1) ? at 100 K and 3.968 (5) ? at 300 K] and inter-chain Cl?Cl [3.630 (3) ? at 100 K and 3.687 (9) ? at 300 K] distances occurred.
The chlorination kinetics of zirconium dioxide mixed with carbon black
Movahedian,Raygan, Sh.,Pourabdoli
, p. 93 - 97 (2011)
In this research, the effects of chlorine gas at different chlorine partial pressures and carbon concentrations on the carbochlorination of zirconia were studied. It was found that in briquettes containing 18.7 %wt carbon, in a chlorine partial pressure range of 0.25-0.75 atm and for a reacted fraction of less than 0.7, the chemical reaction model was dominant for the carbochlorination process of zirconia. The order of reaction into chlorine gas (n) in this situation was 0.57. Moreover, the best weight ratio of carbon to zirconia was 40/60. In this case, the activation energy of the reaction was 209.9 kJ mol-1 in a temperature range of 1023-1223 K, and the dominant model was the chemical reaction model.
REACTION PROCESS OF ZIRCONIUM TETRACHLORIDE WITH AMMONIA IN THE VAPOR PHASE AND PROPERTIES OF THE ZIRCONIUM NITRIDE FORMED.
Yajima,Segawa,Matsuzaki,Saeki
, p. 2638 - 2642 (1983)
The reaction products of gaseous ZrCl//4 with ammonia at 300-1400 degree C were examined in detail. The possible reactions which were considered to occur during the reaction process on the basis of the above experiments were examined. The N/Zr atomic rati
Chemical vapor transport of layer structured crystal β-ZrNCl
Ohashi, M.,Yamanaka, S.,Hattori, M.
, p. 342 - 347 (1988)
A layer structured compounds β-ZrNCl is transported to a higher temperature zone with the aid of ammonium chloride as the transporting agent in the temperature range of 823-1173 K. The transport mechanism can be explained by the formation of a volatile compound (NH4)2ZrCl6. The measurements of the vapor pressure and the mass spectrum revealed that (NH4)2ZrCl6 decomposed congruently according to the equation presented. The enthalpy change for the decomposition was determined to be 533 kJ/mol. By combining the above two equations, a simplified transport equation is derived.
Zirconium recovery from zircaloy shavings
Bohe,Gamboa,Lopasso,Pasquevich
, p. 3469 - 3474 (1996)
A chlorination process for recovering Zr from zircaloy scrap has been studied. Zircaloy chlorination was possible at temperatures as low as 220°C. The scale microstructure and its effect on the zircaloy reactivity was analysed using Thermogravimetric analysis (TGA), X-ray diffraction (XRD), energy dispersive X-ray spectroscopy (EDXS) and scanning electron microscopy (SEM) techniques. A solid-solid phase transformation took place into the oxide scale during the zircaloy chlorination. Zirconium, as ZrCl4(g), was separated from the oxide scale and chlorides of Cr and Fe. The effect of the reaction temperature was also analysed.
Thermodynamic properties of zirconium chlorides. I. The standard molar enthalpy of formation, the low-temperature heat capacity, the standard molar entropy, and the standard molar Gibbs energy of formation of zirconium trichloride
Efimov, M. E.,Prokopenko, I. V.,Tsirelnikov, V. I.,Troyanov, S. I.,Medvedev, V. A.,et al.
, p. 353 - 358 (1987)
The enthalpies of the reaaction of ZrCl3(cr) and of ZrCl4(cr) with 3 mol * dm-3 HCl solution were measured in a 0.1 dm3 reaction vessel of the isoperibol calorimeter LKB-8700.The enthalpy change of the resulting reaction: ZrCl3(cr) + HCl(sln, 17.06H2O) = ZrCl4(cr) + 0.5H2(g), was found to be ΔrHm0(298.15 K) = -(62.6+/-2.7) kJ * mol-1 which leads to ΔfHm0(ZrCl3, cr, 298.15 K) = -(753.9+/-3.0) kJ * mol-1.Heat-capacity measurements between 7 and 312 K were performed on a pure sample of ZrCl3(cr).The following standard molar thermodynamic quantities are reported at T0 = 298.15 K: the heat capacity: Cp,m0(T0) = (92.871+/-0.089) J * K-1 * mol-1; the entropy: Sm0(T0) = (137.50+/-0.28) J * K-1 * mol-1; the enthalpy increment: m0(T0)-Hm0(0)> = (19239+/-29) J * mol-1; and the Gibbs energy of formation: ΔfGm0(T0) = -(685.0+/-1.5) kJ * mol-1.
Titanium, zirconium, and hafnium metal atom reactions with CF4, CCl4, and CF2Cl2: A matrix isolation spectroscopic and DFT investigation of triplet XC÷MX3 complexes
Lyon, Jonathan T.,Andrews, Lester
, p. 2519 - 2527 (2008/10/09)
Laser-ablated group 4 transition metal atoms react with CF4 to form triplet state electron-deficient FC÷MFa methylidyne complexes, which are identified by their infrared spectra and comparison to density functional vibrational frequency calculations of stable possible products. Of particular interest in these complexes are the strong C-X bonds and carbon-metal n bonding. The two unpaired electrons on carbon are drawn to the electron-deficient transition metal center, forming a partially filled triple bond, which is approximately equal in length to a classical C=M double bond. Reactions with carbon tetrachloride form the analogous ClC÷MCl3 complexes, whereas reactions with CF2Cl2 form a mixture of FC÷MFCl2 and ClC÷MF2Cl species. The FC÷MFCl2 complexes involving more α-Cl transfer are favored in the reaction of excited metal atoms during sample deposition, but UV irradiation photoisomerizes FC÷MFCl2 to the lower energy ClC÷MF2Cl complexes with more α-F transfer to the metal center.
CATALYST FOR POLYOLEFIN PRODUCTION AND PROCESS FOR PRODUCING POLYOLEFIN
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, (2008/06/13)
A catalyst component for polyolefin production catalysts comprising a metallocene compound represented by general formula (1) (symbols have the meanings as described in the specification), polyolefin production catalyst containing the component, and metho
Metallocenes, their preparation and use in the polymerization of alpha-olefins
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, (2008/06/13)
Catalytic component for the copolymerization of ethylene with alpha-olefins having general formula (I): STR1 wherein: A is a cyclopentadienyl derivative having general formula (II) STR2 B is selected from: 1) any of the cyclopentadienyl derivatives A defi
