XRD data

X-Ray powder diffraction patterns of the precursors reveal that the complexes are isostructural, possessing the monoclinic structure of N2H5Fe(N2H3C00)3 H20. The unit cell dimensions (Table 4.9) clearly reveal that solid solutions of the type N2H5(Ni, Zni, t)v3Fe 3 (N2H3C00)3 H20 are formed in the entire range of x = 0.2-0.8. 

The IR spectra of all these complexes show the characteristic N—N stretching frequency of N2H3COO in the region 900-1010 cm and that of N2H5+ at 965 cm.  

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For a long time the structural classification of the mineral todorokite was uncertain, until Turner and Buseck [4] could demonstrate by HRTEM investigations that the crystal structure of that mineral consists of triple chains of edge-sharing octahedra, which form [3 x 3] tunnels by further corner-sharing. These tunnels are partially filled by Mg2+, Ca2+, Na+, K+, and water (according to the chemical analysis of natural todorokites). In 1988 Post and Bish could perform a Rietveld structure determination from XRD data taken for a sample of natural todorokite [25], This diffraction study confirmed the results of Turner and Buseck. The cations... 

Figure 1 is a TEM photograph of the Cu (10wt%)/Al2O3 catalyst prepared by water-alcohol method, showing the dispersed state of copper and was confirmed the particle sizes from XRD data. Figure 2 is X-ray diffraction patterns of above-mention catalysts, was used to obtain information about phases and the particle size of prepared catalysts. Metal oxide is the active species in this reaction. Particle sizes were determined fix)m the width of the XRD peaks by the Debye-Scherrer equation. 

Oxidized Alloys. Ternary Intermetalllcs undergo extensive transformation when they are treated In air for 24 hours at 350 C. XRD data Indicate the presence of NIO, Fe2, and Th02. The presence of Nl-Fe alloy could not be confirmed by because of the small dif-... 

The XRD data and Zn/Cu ratio are also given for a reference aurlchalclte specimen reported In the literature ( ). All d-spaclngs In the mineral and synthetic aurlchalclte matched the literature values within the lattice volume changes (<2%) reported In Table 1. Over 30 XRD peaks were used In the XRD comparisons. The XRD analysis established that the structure of the mineral and synthetic aurlchalclte was essentially Identical. The only distinguishing features were the higher Cu content and the 1.6Z smaller unit cell volume of the mineral sample compared to the synthetic sample. 

Extensive data on the charaaerization and the thermal evolution of the different catalysts have been reported elsewhere [9-14]. Phase composition, cell parameters and surface area of the final materials are summarized in Table 1. The XRD data indicate that for all the hexaaluminate-type samples the formation of the final phase begins at 1273 -1373 K and requires calcination temperatures of 1473-1573 K to be completed. 

The series of deviation from a strictly octahedral crystal field follows the sequence ammonium tungstate > tungstic acid > WO3 [14]. The s->d transition becomes allowed as distortion of the octahedral environment increases. Viewed as a fingerprint technique. Figure 6 shows that the bulk of W present in both WZ (calcined) and PtWZ(acac, reduced) behaves as WO3, as also shown by our XRD data [10], sugesting that only a small extent of W reduction is expected to have taken place during catalyst conditioning prior to reaction. 

As research progresses over the years it is becoming apparent that the majority of these cements are essentially amorphous, and that crystallinity is secondary and sometimes very slight. Kingery s arguments based solely on XRD data are, perhaps, not very relevant. 

The XRD and TEM showed that the bimetallic nanoparticles with Ag-core/Rh-shell structure spontaneously form by the physical mixture of Ag and Rh nanoparticles. Luo et al. [168] carried out structure characterization of carbon-supported Au/Pt catalysts with different bimetallic compositions by XRD and direct current plasma-atomic emission spectroscopy. The bimetallic nanoparticles were alloy. Au-core/Pd-shell structure of bimetallic nanoparticles, prepared by co-reduction of Au(III) and Pd(II) precursors in toluene, were well supported by XRD data [119]. Pt/Cu bimetallic nanoparticles can be prepared by the co-reduction of H2PtClg and CuCl2 with hydrazine in w/o microemulsions of water/CTAB/ isooctane/n-butanol [112]. XRD results showed that there is only one peak in the pattern of bimetallic nanoparticles, corresponding to the (111) plane of the PtCu3 bulk alloy. 

Figure 9.21 Specific activity and Pd-Pd bond distance calculated from XRD data against the concentration of Fe in Pd-Fe/C elecfrocatalysts treated at 500 °C. (Reproduced with permission from Shao et al. [2006c].)...

Shown in Figure 15.5 are the temperature dependent XRD data for the 5% Pd-1% Sn catalyst. As noted above, the scans were offset in the order that they were obtained (the Time axis, as shown, is the scan sequence number and not the actual temperature). The inset of Figure 15.5 illustrates the temperature profile for the scan sequence. The first scan was obtained at room temperature, at which time hydrogen was introduced into the chamber at 500 Torr. The temperature was then ramped in 10°C increments to 160°C and XRD scans were taken after each increment. The sample was held at 160°C for I/2 hour, and then cooled to room temperature. After I/2 hour at room temperature, the sample was purged with dry nitrogen. 

Even with the diborylacetylenes illustrated by structures 39a-c, XRD data again show a shortening of the B—C bond as more electronegative groups are affixed to the boron centers but only a modest contraction of the C=C bond36 ... 

Of enormous interest to our present discussion would be XRD data on monomeric boroles in order to determine the structural consequences of 7r-electron delocalization in this four-electron, formally antiaromatic system.30 However, many attempts to grow suitable crystals of 94 have failed, and prolonged storage of solutions has produced only yellow dimers, presumably similar in structure to 100. Hence, in estimating the relative importance of structures 94a-c, spectral data must be our guide. 

Fig. 7.3 XRD data of nano CaC03 crystals at different conditions (a) without ultrasound (b) 10 mm probe without hole (c) 10 mm probe with hole (d) 14 mm probe without hole...

XRD data for selected samples are shown in Table 1. The interplanar spacings, doo2 and doo4, were evaluated from the positions of the 002 and 004 peaks respectively by applying Bragg s equation. The crystallite size Lc along the c-axis was calculated from the 002 peak using the Sherrer formula... 

The synthesis procedure led to a highly crystalline MCM-22 zeolite, as indicated by XRD data (Fig. 1A, a). The introduction of platinum by ion exchange procedure does not modify the crystallinity of the zeolite (Fig. 1A, b). SEM micrographs show that the sample obtained in static hydrothermal conditions is characterized by the presence of homogeneous round-shaped particles of ca. 10 pm in diameter formed by aggregation of lamellar particles [7,8], The morphology of the zeolite is not modified after platinum introduction (Fig. IB). 

CAL-4 was prepared according to the procedure described in reference 2. Powder XRD confirmed the absence of contaminant phases. 13C MAS NMR spectra were recorded under cross polarization conditions (CPMAS). Single-crystal XRD data were collected at room temperature using MoK radiation. 

Figure 3.8. Powder XRD data (Cu Ka radiation) for the film achieved by spin-coating the In2Se3 precursor, with a final anneal at 350 °C in an inert atmosphere (film thickness -110 A). 

Roughly, 0.18% of the total mineral composition containing Fe203 in the brown clay was detected by XRD. Other minerals like quartz, K-feldspar, muscovite, microcline, mica, and pyrite were also identified by XRD data. 

ABSTRACT The kinetics and mechanisms of the phase transformation of 2-line ferrihydrite to goethite and hematite are being assessed as a function of pH, temperature and Fe/As, Fe/Se, Fe/Mo molar ratios using batch experiments, BET analyses, XRD, and XANES. Initial results from XRD analyses show that ferrihydrite is stable at high pH ( 10) for up to seven days at 25°C, but considerable crystallization occurs at elevated temperatures. Specifically, XRD data show that ferrihydrite is transformed to a mixture of hematite and goethite at 50°C (-85% hematite and -15% goethite) and 75°C (-95% hematite and -5% goethite) after 24 hours and these ratios remain constant to the end of the experiments (seven days). 

Although additional analyses of the existing data and additional experiments are required to reach definitive conclusions on the phase changes of ferrihydrite in uranium mine tailings, preliminary XRD data suggest that in deionized water at elevated pH (pH=10) phase transformation of ferrihydrite can occur at elevated temperatures. In both elevated temperature experiments, hematite appeared to be the dominant transformation product. At room temperature, however, ferrihydrite remains stable after the duration of the experiment (seven days). 

Figure 6.19 Catalytic in situ reactor made of a quartz capillary, suitable for use at synchrotrons for the collection of EXAFS an XRD data. The scheme of the synchrotron beamline shows the positions of the mono-chromator, the ion chambers which measure the intensity of the X-rays before and after the sample, and the position-sensitive X-ray detector which records the XRD diffractogram (adapted from Clausen [44]).

When tripropylamine or tributylamine is used instead of the corresponding Alk N salt, ZSM-5/11 mixed phases (intergrowths ) are formed, suggesting that the Alk N species are less efficient in directing a specific structure. Unexpectedly, Bu N yields essentially a ZSM-5-rich phase while ZSM-11-rich phases are preferentially obtained with Pr N (XRD data). When an organic molecule acts as template towards (alumino)silicate species to form an ordered zeolitic framework, the latter is supposed to organize itself around the host organic species in such a way that a complete... 

Figure 6. XRD data indicating formation of vanadium hydride on cooling to room temperature under...

Powder X-ray diffraction (XRD) data were collected via a Siemens D5005 diffractometer with CuKa radiation (A. = 1.5418 A). Routine transmission electron microscopy (TEM) and Z-contrast microscopy were carried out using an HITACH HD-2000 scanning transmission electron microscope (STEM) operated at 200 kV. Nitrogen gas adsorption measurements (Micromeritics Gemini) were used to determine the surface area and porosity of the catalyst supports. Inductively coupled plasma (ICP) analysis was performed via an IRIS Intrepid II XSP spectrometer (Thermo Electron Corporation). 

To determine the phase properties of the calcined bimetallic nanoparticles, a detailed x-ray diffraction (XRD) study was carried out. The XRD data of AuPt/C showed that the diffraction patterns for the carbon-supported nanoparticles show a series of broad Bragg peaks, a picture typical for materials of limited structural coherence. Nevertheless, the peaks are defined well enough to allow a definitive phase identification and structural characterization. The diffraction patterns of Au/C and Pt/C could be unambiguously indexed into an fcc-type cubic lattice occurring with bulk gold and platinum. We estimated the corresponding lattice parameters by carefully determining... 

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