Automated diffractometer

In situ XRD stndies of thermally and chemically induced transformations were monitored with a totally automated diffractometer-micrometer system (9). Samples were thermally ramped in 5°C increments from 30 to 160°C, maintained at 160°C for 0.5 hr, and then cooled in 5°C increments to 30°C under 500 torr hydrogen. 20 scans were obtained after each temperatnre increment. The individnal scans conld be stacked to show the temperature evolution of the stracture. 

Now that automated diffractometers and sophisticated computer data-reduction systems have become routinely used, the task involved in conducting an X-ray crystal-structure examination has been enormously simplified. As a result, the number of structures determined each year by crystallography has escalated dramatically. The logistics of maintaining this series in the original form would now entail such stupendous demands on our space that a volume of Advances could be completely occupied by this one article alone. As the original purpose of this series... 

The three dimensional structure was obtained by means of single crystal X-ray diffraction. CuKa radiation, a graphite monochromator, and a photomultiplier tube were used to collect 1825 total reflections on an automated diffractometer. Of these, 1162 were used for the analysis. Figure 2 shows a computer generated drawing of halcinonide. The position of the chlorine atom was not clear from the Patterson map, but the direct method program "MULTAN" gave its position. 

Automated diffractometer A computer-controlled instrument that automatically meMures and records the intensities of Bragg reflections. The required mutual orientations of the crystal and the detector with respect to the X-ray source are computed from initial data on 20-30 selected Bragg reflections. These orientations are then achieved by computer-directed commands to electromechanical devices that position the crystal orienter and X-ray detector at the desired angular settings. 

The catalysts used and their physico chemical properties are listed in Table 1. Powder XRD patterns of the calcined samples were recorded on a computed automated diffractometer... 

Single-crystal x-ray studies of the contact-ion pair complexes shown in Table II have been completed. The data were measured with a Picker automated diffractometer, and the structures were solved by direct methods. Hydrogen atom positions were included in all the structures but usually not refined. Refinements of the structures were made using a full-matrix, least-squares technique with neutral-atom scattering factors. 

Most of the single crystal structure determination experiments are based on the use of automated diffractometers. 

The XRD studies of the samples prepared were conducted with an automated diffractometer DRON-UMl using Ni-filtered CuKa radiation. The comparison of the XRD patterns of the samples prepared with the literature data on ZSM-5 (Argauer and Landolt 1972) shows that the x-ray spectrum lines for these samples correspond to the spectral lines of ZSM-5. The degrees of crystallinity of samples 1 and 2 were 100% and 66%, respectively. The specific surface area of the silicalite samples measured by the method of LT adsorption of nitrogen was 312 and 240 mVg,... 

Collection of Diffraction Data for 4b. A red crystal of dimensions 0.40 X 0.30 X 0.25 mm was selected, mounted on a glass fiber and coated with epoxy. Diffraction data were collected on a Rigaku AFC6S automated diffractometer. Cell parameters were refined by full-matrix least squares from the positions of 25 well-centered reflections foxmd in the region 25.0 < 26 < 30.0° and indicated a monoclinic cell. 

To better understand the axial expansion characteristics of compositions in CaZr4(P04)6-MgZr4(P04)6 system, high temperature XRD was used to determine lattice parameter fluctuations upon heating. Powder samples were made by solid-state reaction methods. The compositions CaZr4(P04)e, (Cao.8.Mgo.2)Zr4(P04)6, and (Cao.7,Mgo.3)Zr4(P04)6 were selected for analysis. Samples were mixed with a pure Pt powder (for use as an internal standard) and scanned with a Scintag 0-0 fully-automated diffractometer equipped with a... 

C/min were used. IR spectra were recorded with a Bomem Michelson 110 FT-IR spectrophotometer at a resolution of 4 cm The sample was dispersed in a KBr pellet 50 scans were used for each spectrum. Flat plate X-ray patterns were recorded under vacuum on Kodak No-Screen film using Ni-filtered Cu Ka radiation (X - 1.5418 A) and a Searle toroidal focusing camera with pinhole collimation. WAXD spectra were also recorded as diffractometer scans, using a Phillips APD 3520 automated diffractometer using Ni-filtered Cu Ka radiation in the reflection mode. 

The Qualitative determination of major crystalline phases was achieved using the Philips X Pert Pro automated diffractometer equipped with a Ge (111) primary monochromator. Chemical composition was determined by X-ray fluorescence (XRF) using the Philips Magix Pro (PW-2440). Thermal behaviour was determined by thermogravimetric and differential thermal analysis (TGA-DTA) with a Mettler Toledo 85 le device in oxygen operating at a ramp of 20 °C/min from room temperature to 1000 °C. 

The experimental apparatus commonly involve a sealed-tube or rotating-anode X-ray source, a 2-circles (for powders) or a 4-circles (for single crystals) automated diffractometer for sample orientation with respect to the incident beam, and one or more detector banks for detection of the diffracted signal. The angular position, the integrated intensity, and the peak profile shape of the diffracted signal are important for the subsequent analysis. 

Outline how you would interpret X-Ray diffraction data, if any, obtained for the following CPs and using the following X-Ray methods P(ANi)Cl P(Di-Ac)s Debye-Scherrer powder camera Weissenberg camera Precession camera Wide Angle X-Ray Diffraction Automated Diffractometer. 

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