Recently, Dahan and co-workers (Dahan, 1991) suggested processing the XRD data by spreadsheet computer programs. Treated in this manner the XRD data became very flexible and made comparison with other data sets, as well as graphical presentation, much easier. In this note a simple FORTRAN 77 program for conversion of PC-APD data files into ASCII files suitable for import into spreadsheets is reported.

In our laboratory XRD data are collected on a Philips 1710 diffractometer operated by the PC-APD version 2.0 (PC-APD Software, 1989). Each experiment usually generates its files containing collected raw intensity data (.RD file), background data (.BK file) and file with peak positions and their intensities (.DI file). The XRD data can be further processed: after smoothing, data are stored in files with extension .SM (.SM file) and, after Kα2 stripping, into files with extension .A2 (.A2 file). All files are stored in the binary format.

The structure of pyrochlore type Y2Sn2O7 has been refined by Rietveld analysis from 1.4925 Å neutron powder diffraction data collected at 295 K and containing 46 independent reflections. The refinement figures of merit were Rp = 0.041, Rwp = 0.055, Rexp = 0.039, and RB = 0.006. The structure is a pyrochlore type, space group (S.G.) with a = 10.3723(1) Å, Dx = 6.21 g cm−3, and with the oxygen position parameter of 0.33694(5). The Sn atoms are in a nearly regular octahedral coordination whereas the Y has a distorted 8-fold coordination geometry. The anisotropic thermal parameters were also determined. The refined model has been used to calculate a set of d-I X-ray data for search/match analysis.

Possibilities and restrictions of least-square methods for mica cell refinement are briefly described. If diffractometric raw data are precise and accurate, and if geometrical errors are properly corrected, a cell refinement (determination of ao, bo, cO, β) can be carried out rapidly, but the reliability of obtained data has to be evaluated carefully.

A precise X-ray powder diffraction pattern of the orthorhombic form of InVO4, InVO4-III, was obtained using a Huber camera with CuKα1 radiation (λ=1.5406 Å) and Si as internal standard (a= 5.4308 Å). Refinements of indexed reflections led to the following parameters: a=5.7531(3)Å, b=8.5201(4)Å, c=6.5781(3)Å, space group Cmcm, Z =4, Dx=4.733 g/cm3, Dm=4.65 g/cm3. The Smith–Snyder figure-of-merit is F30=201.4 (0.004, 34).

K2YZr(PO4)3and K2GdZr(PO4)3were found to have the langbeinite-type structure (K2Mg2(SO4)3). We determined the crystal structure of these compounds from powder diffraction data. They are cubic P213 (no. 198), with a = 10.3346(1)Å and a = 10.3457(3)Å respectively. The intensity values we observed and calculated are reported. Intensity measurements indicate a random distribution of Y3+(Gd3+) and Zr4+on both Mg2+sites of langbeinite.

In the absence of single crystals, silver(I) 3,5-dimethylpyrazolate, [Ag(dmpz)]3, has been structurally characterized by ab initio X-ray powder diffraction, using conventional laboratory data. Its crystals are triclinic, P1¯, with a=8.0876(10), b=11.1204(13), c=11.6136(16) Å, α=68.293(6), β=78.350(7), and γ=81.243(6)°. The structure has been solved by Patterson, difference Fourier, and geometrical modeling, and ultimately refined by the Rietveld method down to Rp=0.068, Rwp=0.085, and RF=0.055, for 4300 observations in the 17<2θ<103° range. Each molecule consists of a cyclic, trimeric assembly of Ag(dmpz) fragments, with the dmpz ligand bridging, in the exo-bidentate mode, nonbonded Ag…Ag edges.

An interactive computer program to display, process and analyze raw powder X-ray diffraction data is described. The program extensively employs graphic means of input and output with the help of “pop-up” windows and menus. In addition to those tasks that are common to most primary raw data analyzing programs, it performs many functions which are generally assigned to separate secondary programs. These functions include on-screen correction of d-spacing with reference to a standard compound, calculation of peak width and crystallite size, subtraction of patterns for differential X-ray diffraction and unrestricted overlay of patterns. The advantages of an integrated single program to process X-ray diffraction data in mineral research are illustrated and discussed.

The powder diffraction pattern for p-Iodotoluene C7H7I at 293 K (P212121, No. 19, Z = 4) is given. The cell parameters found are a = 16.484(2) Å, b = 7.444(2) Å, c = 6.108(l) Å.

Powder X-ray diffraction data of melatonin C13H16N2O2 were collected on a conventional X-ray powder diffractometer: the monoclinic cell parameter are a=7.7416(8) Å, b=9.2897(9) Å, c=17.1444(16) Å, β=96.756(9)°, volume 1224.4(3) Å3 (space group P21/c). The strongest lines are (d (Å), I/I0) 8.161 (100), 5.411 Å (46), 3.412 Å (34), 4.668 Å (33), 4.645 Å (25), 3.554 Å (22), 3.668 Å (16), and 4.483 Å (14). Reported intensities are validated by Rietveld analysis. The data consist of measured positions and intensities and cover an angular range up to 60° 2θ: experimental, calculated, and difference patterns are also reported.

In this paper we present a high temperature heating device, working under defined environmental conditions, for a Siemens D500 Bragg–Brentano powder diffractometer. The powder sample is prepared in a flat mould on a metal block consisting either of copper or of platinum depending on the temperature range selected for investigations. Although the heating cell can be used separately under ambient conditions up to sample temperatures of 1000 °C, it is possible to work under defined environmental conditions in the temperature range between 20 and 200 °C and up to a water vapour pressure of 1000 mbar. For that purpose a special cover for the in situ control of temperature and water vapour pressure has been constructed. It is important to note that the three sample conditions (sample temperature, gas temperature, and gas humidity) can be adjusted separately by the user. Current studies have shown that the described X-ray heating device is a powerful tool to study dehydration reactions in the frame of fundamental research as well as to understand industrially relevant processes concerning dehydration reactions and their mechanisms.

A Rietveld refinement of X-ray powder diffraction data for orthorhombic BaNd2Mn2O7 is reported. The refined lattice parameters were a=0.5517(5), b=0.5482(3), and c=2.0585(7) nm with space group Fmmm (No. 69).