Standardized experimental and calculated X-ray powder diffraction data for a new synthetic zeolite, cesium titanium silicate, CsTiSi2O6.5, are reported. In addition, a structure model in space group Ia3d (230), which is isomorphous with the mineral pollucite (CsAlSi2O6·xH2O), is proposed for CsTiSi2O6.5. This structure model is the basis of the reported calculated X-ray powder diffraction data for CsTiSi2O6.5. The experimental pattern for CsTiSi2O6.5 shows this compound crystallizes in a body-centered cubic (BCC) unit cell with a=13.8423 (1) Å. The measured value of the reference intensity ratio (I/Ic) of CsTiSi2O6.5 is 2.37, while the contrasting calculated value of I/Ic is 4.45. The experimental density (Dm) of CsTiSi2O6.5 is 3.48±0.09 g/cm3, in agreement with the calculated density (Dx) of 3.42 g/cm3. Chemical analysis of CsTiSi2O6.5 by atomic absorption spectroscopy gives its composition as 54±2 wt% Cs; 23±2 wt% Ti; 23±2 wt% Si, which compares favorably with the theoretical composition of 56 wt% Cs; 20 wt% Ti; 24 wt% Si.

Synthesis of high-purity, single-phase gallium nitride (GaN) powder has been achieved by reacting molten Ga with flowing ammonia (NH3) in a hot wall tube furnace. The optimum temperature, NH3 flow rate, and position of the boat in the hot wall tube furnace relative to the NH3 inlet for the complete reaction to pure GaN for our system were 975 °C, 400 standard cubic centimeters per minute (seem) and 50 cm, respectively. The X-ray diffraction (XRD) data revealed the GaN to be single phase with a = 3.1891 Å, c = 5.1855 Å, in space group P63mc, Z=2 and Dx =6.089 g cm−3. Scanning electron microscopy revealed a particle size distribution in the crushed material between 1 and 5 μm with most of the particles being ≍1 μm.

X-ray powder diffraction data and refined unit cell parameters for the (Bi, Pb)2Sr2Ca2Cu3Ox (2223) superconducting phase, indexed using incommensurate modulation principles, are reported. Comparison of the results obtained with one- and two-component modulation wave vectors showed that the two-component modulation wave vector is superior for indexing the satellite reflections. A two-component wave vector indexing result seems likely when only the powder diffraction data are considered.

A new X-ray powder diffraction pattern for α-Si3N4is presented and compared with the current PDF pattern. The necessity for an updated pattern is discussed.

New powder X-ray diffraction data of Ca12Al14O32F2 (C11A7f), a cementitious compound, were collected on a conventional X-ray powder diffractometer; the cubic cell parameter is a=11.96269(6) Å, volume 1711.93(2) Å3 (space group I-43d (No. 220)). The strongest lines are 4.887(100), 2.676(95), 2.992(46), 2.443(46), 2.185(37), 3.198(32), 1.599(26), and 1.941(25). Reported intensities are validated by Rietveld analysis. The new data consist of measured intensities and cover a wider 2θ angular range with respect to the calculated PDF 25-394 and the indexed PDF 36-678: experimental, calculated, and difference patterns are reported together with crystal-chemical considerations.

The indexed X-ray diffraction powder data of sodium triaqua-hexa-(nicotinato-tri-μ-oxo-tri-chromium(III) perchlorate) hexahydrate {Na [Cr3 O(C6H5NO2)6(H2 O)3] [ClO4]8·C6H5NO2·6H2O, NICCR} is reported. NICCR crystallizes in the hexagonal space group P63/m. The refined cell parameters were determined by employing a Siemens Debye-Scherrer camera (Fe Kā radiation, λmean= 1.93736 Å). The cell constants are a = 13.573(2), c = 24.901(5) Å, V = 3972.8 Å3 and Dx =1.68 Mg m-3 (Dm =1.67 Mg m-3). The quantitative figure of merit (FN) for NICCR is F27 = 32(0.010,81). The JCPDS Diffraction File No. is 36–1978.

The utility of ultra-high-temperature (2100 °C) X-ray powder diffraction technique for investigating the high-temperature phase relationships of two pseudobinary mixtures, Al2O3/Y2O3 and AlN/SiO2, is described. The in situ analysis to 1600 °C was carried out using a platinum holder and a Pt/Rh thermocouple; whereas analysis beyond 1600 °C was performed with a tungsten holder, extremely pure, oxygen-free inert gas environment, and an opticalpyrometer to monitor temperatures up to 2100 °C. The solid-state interaction between Al2O3 and Y2O3 commenced with the formation of Al2Y4O9 (YAM), a yttria rich compound, at 1300 °C followed by AlYO3 (YAP) and Al5Y3O12 (YAG) at 1400 °C. Further heating to 1500 °C and above resulted in the increased concentration of YAG at the expense of the other two phases, followed by melting of the entire sample at 2050 °C. The only phase formed during cooling (from the molten state) was YAG. AlN and SiO2 did not react with each other, in an inert atmosphere, and they remained as separate, discrete phases even at 1600 °C. In the presence of oxygen, they reacted to form mullite and cristobalite, or SIALON depending on the partial pressure of oxygen.

Numerous spurious X-ray peaks were encountered during grazing incidence angle diffractometer scans of ceramic and polymeric thin films on crystalline and amorphous substrate materials. At least three possible sources of spurious peaks are identified. (1) At (2θ) values greater than ∼ 10°, Laue reflections from characteristic and Bremsstrahlung continuum radiation produce spurious peaks with a (2θ) dependence on X-ray incident angle and sample orientation. At (2θ) values less than 10°, (2) specular X-ray reflection from a boundary between two media of different indices of refraction and (3) diffuse surface scattering produces spurious peaks with a dependence on X-ray incident angle and sample surface topography. From an understanding of the spurious peaks, improved experimental techniques may be developed. Because these peaks can interfere significantly with grazing incidence diffractometer scans, it is particularly important to those making studies of thin films by this asymmetric diffraction geometry to be aware of the existence and origins of these spurious peaks.

Use of the overlap integral in X-ray diffraction (XRD) powder pattern recognition of crystalline materials is presented. The mathematical expression, derived specifically for diffraction data, provides a measure of similarity between two patterns. Each pattern is represented by a normalized mathematical function. The index of similarity, or overlap integral, indicates how faithfully the two functions overlap and ranges from zero to unity, reaching the latter limit when the two patterns become identical.

The intensity round-robin is one of a series of round-robins sponsored by the International Centre for Diffraction Data. The purpose of these round-robins is to attempt to quantify problems encountered in the acquisition, analysis and interpretation of powder diffraction data. Previous International Centre sponsored round-robins have addressed topics including: manual and automated search match methods; sample preparation methods; d-spacing accuracy; cell parameter refinement and peak profile calibration.

The primary focus of the intensity round-robin was to study measured intensities obtained from modern computer controlled powder diffractometers. However, the tests were designed in such a way as to also yield information on the performance of data treatment software packages. To this end, participants were asked to submit both raw and treated data, thus allowing evaluation of, for example, the efficiency of peak hunting algorithms in finding peaks.