A deformed aluminum-copper alloy was studied by X-ray diffraction. The 111 diffraction profile was found to consist of a main peak and a subpeak. They were separated by a numerical differential method combined with a non-linear least square profile fitting procedure. The subpeak could not be ascribed to the θ phase in the alloy since the intensity ratio of the subpeak to main peak is 20-30 times more than the volume ratio of the θ phase to die matrix. On the other hand, the Transmission Electron Microscope (TEM) micrographs showed clearly that there is a highly inhomogeneous dislocation distribution just like the cell structure in pure aluminum. The main X-ray peak was thus assumed to be due to diffraction from the cell interior while the subpeak is determined by the cell wall. After applying a series of standard data processing procedures based on Wilkens' theory and the Pearson VII-Voigt function, the dislocation densities in both the cell interior and wall were evaluated.

X-ray powder diffraction data show that the highest temperature solid phase of C4F8 has an orientationally disordered body-centered cubic structure, a = 7.06(3)Å, with two molecules per cell.

The method described in this paper is a strict protocol for X-ray diffraction (XRD) analysis of mineral phases found in soils. Its application is not restricted to soils and is an attempt to standardize XRD sample preparation and analysis. The protocol requires the particle size of the < 2 mm - 0.002 mm fraction be reduced to 0.002 mm before analysis. In die qualitative section, the clay fraction ( < 0.002 mm particle size) is prepared as oriented slides. The suspended clay fraction is saturated with ethylene glycol, K +, and Mg+2; pipeted; air-dried; heat-treated at 110°C, 350°C, and 550°C; and X-rayed at each step in order to properly identify the clay minerals. In the quantitative section, the method employs a matrix-flushing agent, corundum (Al2O3). The corundum acts also as an internal standard, a calibration standard, and a reference standard. The suspended clay fraction is freeze-dried and corundum is added to each sample. Randomly oriented powder mounts are prepared from the < 2 mm - 0.002 mm fraction, and the < 0.002 mm fraction, and X-rayed. A series of reference standards are prepared based on the existing mineralogy, corundum is added, and each mixture is X-rayed. The software integrates the area under specific peaks (chosen for intensity and no overlap) in each sample, calculates the reference intensity ratios (RIRs) and calculates the percentage of each mineral based on the equation of Chung (1974). The attention to detail allows documentation and verification of the results yielding data of known quality.

The X-ray powder pattern of a partially combusted coal product has been separated into its diffraction component (caused by die crystalline minerals present in the sample) and its amorphous scattering component which is due to the fixed carbon retained in the sample. Analysis of the atompair intensity of the amorphous scattering component indicates that the molecular scatterer(s) in the fixed carbon fraction are similar, at least in short range structural details, to those in an amorphous carbon black sample which was prepared by high temperature combustion of polynuclear aromatic materials.

The fly ash Standard Reference Materials (SRMs) issued by the U.S. National Bureau of Standards have been studied by X-ray powder diffraction (XRD). Based on observations of large diffuse scattering maxima in their X-ray diffractograms, it was evident that all of the ashes had a high glass content. SRM 1633a and 2689, derived from the combustion of bituminous coal, contained different amounts of quartz, mullite, hematite and ferrite spinel (magnetite). SRM 2891, derived from subbituminous coal had quite a different chemical composition and a more complex crystalline phase assemblage, that included these four phases plus anhydrite, tricalcium aluminate, lime, periclase and minor phases. SRM 2690, also derived from subbituminous coal, had only quartz, mullite and ferrite spinel as detectable phases in its diffractogram. Analytical CaO is an important factor in determining the phase assemblage; SRM 2691 had 25.8 wt%, SRM-2690 had 8.0%, and the ash derived from bituminous coals had only 1.6-3.0%. The changing composition of the glass phases in the SRMs is detected in a shift in the position and shape of the diffuse scattering maximum in the diffractograms. Use of an internal intensity standard permitted quantitative comparisons of the relative amounts of crystalline phases among the four fly ash SRMs.

A discrepancy was discovered between an experimental X-ray diffraction pattern of sodium acetate trihydrate collected with the Gandolfi camera and a calculated pattern based on a single crystal study of the same compound. The experimental d spacings matched those of the calculated pattern with the exception of the strongest reflection d = 3.002 Å (h k l = 40 − 2) which was missing in the experimental pattern. Another experimental Gandolfi pattern obtained from a powdered sample of sodium acetate trihydrate gave excellent agreement with the calculated d spacings and intensities.

The results of our investigation into this discrepancy show that the angle θ, crystal alignment, camera diameter, and the crystal system can affect diffraction in the Gandolfi camera. It is shown that all reciprocal lattice points with θ angles less then 10.08° would diffract in the film plane of the 114.6 mm Gandolfi camera and points with θ angles less then 20.49° would diffract in the film plane for the 57.3 mm camera regardless of the crystal system or alignment. However, reciprocal lattice points aligned along the spindle axis of the 114.6 mm Gandolfi camera having reciprocal lattice points with Z ≥ 0.35 reciprocal lattice units (r.l.u.) and X and Y ≤ Z-0.35 r.l.u. will not diffract into the recording plane of the Gandolfi camera. The reciprocal lattice points aligned along the spindle axis of the 57.3 mm Gandolfi camera with Z ≥ 0.70 r.l.u. and X and Y ≤ Z-0.70 r.l.u. will not diffract into the recording plane of the camera.

An expanded X-ray quantitative phase analysis method is presented. It is an extension of the method without standards. In order to get the method applied more extensively, there is a discussion at the end of this paper of the suitability of samples.

The diffraction patterns of coarse grained materials are compared to specimens with crystallite sizes of less than 1 µm characterized by diffraction spots. Based on an analysis of spot intensities it is shown that for: (a) an at-random distribution of crystallite orientations and (b) under the assumption of specific crystallite shapes it becomes possible to evaluate the distribution N(l) of linear crystallite dimensions (0.1 µm < l < 20 µm) from measured spot intensity distributions z(i).

X-ray powder diffraction data, unit cell parameters and chemical data published previously for kutnohorite, the manganese-rich double carbonate mineral, are critically evaluated and compared with new measurements on a specimen from Chvaletice, Czechoslovakia with a composition Ca (Mn0.64Mg0.23Fe0.13)(CO3)2. Data were collected with a computer controlled diffractometer and analysed with profile analysis techniques. The new powder diffraction data set yields much better data and unit cell parameters than the earlier ones given for kutnohorite on PDF 11-345 (Powder Diffraction File, 1987). A least-squares evaluation resulted in ao = 4.8518(3)Å and co = 16.217(2)Å.

The structure of TeO3, first published by Dumora and Hagenmuller (1968), was redetermined from new X-ray data collected with a powder diffractometer using space group R3̄c with a = 4.901(2), c = 13.030(4) Å, V = 271.05(8) Å3 and Z = 6. Intensity data were obtained with CuKα, radiation (λ = 1.540598 Å). Structure refinement was performed with 49 reflections and led to R = 0.058. The material is isostructural with FeF3. Powder data are given.

Indexed X-ray diffraction powder data for {[Cr3O(C6H5NO2)6(H2O)3](CIO4)7 · 3NaCIO4·0.5(C6H5NO2)· 3H2O}, INICCR (isonicotinato) and {[Cr3O(C6H5NO2)6(H2O)3] (CIO4)7·6NaCIO4·3H2O}, PICOCR (picolinato) are reported. Both INICCR and PICOCR crystallize in the hexagonal space group P63/m. Crystal data determined for INICCR are a = 13.838(3) Å, c = 25.038(8) Å, V = 4152.2 Å3, Dx = 1.71 Mg m−3 (Dm = 1.66(5) Mg m−3), F25 = 26.5(0.020,47) and for PICOCR are a = 13.966(4) Å, c = 24.518(6) Å, V = 4141.5 Å3, Dx = 1.96 Mg m−3 (Dm = 1.94(4) Mg m−3), F21 = 17.9(0.023,51). The JCPDS Diffraction File Number for INICCR is 38-1992 and for PICOCR is 38-1993.

The following fourteen reference patterns of boride, telluride, and oxide ceramics are reported. Included in the fourteen reference patterns are data for six high Tc superconducting oxide and related phases (Ba2CaCu2TI2O8, BaCuEu2O5, BaCuTm2O5, BaCuDy2O5, Ba3.2Cu1.7Y0.8O6.1·xCO2, Sr2Bi2O5). The general methods of producing these X-ray powder diffraction reference patterns are described in this journal, Vol. 1, No. 1, pg. 40 (1986).

Samples were mixed with one or two internal standards: silicon (SRM640a), silver, tungsten, or fluorophlogopite (SRM675). Expected 2θ values for these internal standards are specified in the methods described (ibid.). Data were measured with a computer controlled step-scanning diffractometer. The POWDER-PATTERN system of computer programs was used to locate peak positions, to calibrate the patterns, and to perform variable indexing and least-squares cell refinement. A check on the overall internal consistency of the data was also provided by a computer method.

Intensities were measured as peak heights above background and were read manually from strip charts. To minimize preferred orientation effects, the powders were passed through a 400 mesh sieve and were mixed with an amorphous diluent, silica gel. Sample mounts were prepared by side-drifting and/or by dusting a thin layer of sample on a glass slide coated with a thin smear of silicone grease.