A novel approach to the determination of crystallite size and lattice strain by means of Total Pattern Analysis is described. Parameters to define the position, magnitude, breadth and shape of individual peaks are obtained by an adaptation of the pattern fitting program of Sonneveld and Visser (J. Appl. Cryst. 8, 1–7, 1975). A rapid assessment of the nature of the specimen broadening is given by a Williamson-Hall Plot. This leads to a more detailed study of line breadths by, for example, Voigt analysis applied to several orders of reflections or to single lines. Preliminary results are given for the application of this procedure to ‘size only’ and ‘size-strain’ samples of ZnO.

A conventional semi-automated powder X-ray diffractometer that was previously equipped with a strip chart recorder for data acquisition has been interfaced to an HP 1000 minicomputer via an analog-to-digital converter. Data acquisition and analysis is now accomplished using CALS chromatographic software and two in-house-developed FORTRAN 77 computer programs. This has resulted in significant improvements in experimental repeatability and accuracy, decreased sample turn-around times, and rapid and facile analysis, manipulation, and comparison of crystallographic data.

A unique file structure and search algorithm have been developed for the purpose of obtaining matches between experimental electron diffraction and qualitative energy dispersive X-ray compositional data from an unknown crystalline phase and the reference data in the JCPDS Powder Diffraction File. The reference data for over 32,000 inorganic compounds from sets 1–33 were compressed and stored in binary format as bit pattern maps. The entire data set and searching programs require less than 4 Mbyte and retain the precision appropriate for electron diffraction analysis. The search algorithm, written in both RT-11 FORTRAN and Flextran, is based on pattern matching between bit maps obtained for the unknown and reference compounds for both composition and diffraction data. Special attention is given to double diffraction effects commonly encountered in electron diffraction analysis. The programs run on an interactive basis on a microcomputer dedicated to the X-ray energy dispersive spectrometer on an analytical electron microscope. A typical search takes about 15 seconds to run and extracts about 10–15 different compounds.

A simple, practical search/match program, RIFRAN 85, has been written and implemented for the EMG 666B programmable calculator. The computer programs are written in EMG Assembler, which is identical to the assembler language for the Hewlett-Packard 9821 calculator. The EMG 666B is made in Hungary and has 8 kbytes of operational memory. The programs interactively provide qualitative phase analysis of X-ray powder diffraction patterns using standard files collected from published data and stored on a compact magnetic tape cassette. Each standard pattern can comprise up to 35 two-theta — intensity pairs. The identification procedure is based on the comparison of the diffraction data of the standard and of the unknown within limits imposed by user-established match and chemical criteria. This paper describes the algorithm used and the performance of the RIFRAN 85 identification system. The system's operation is illustrated using an example of phase analysis of a mineral sample.

Highly uniform fine powder sample layers may be prepared for X-ray diffractometry by aerosol suspension and collection on glass fiber filter substrates. A tubular aerosol suspension chamber (TASC) has been fabricated for this purpose. Essential components include a 500 ml gas buret, 4.7-cm filter cassette, rotameter, and rotary pump. Aerosol particles are generated within the TASC buret by convection within a fluidized bed of glass beads mixed with the sample. Exceptional uniformity of load and randomness of particle orientation has been demonstrated for samples prepared with this system. For quantitative analytical work accurate intensities may be obtained using corrections to raw intensities based on fundamental sample and filter properties.

Twenty-four coal samples representing the four major rank types were analyzed by the X-ray RIM methodology which includes mass absorption analysis by X-ray transmission and quantitative X-ray powder diffraction. Twenty-three separate mineral species were observed in the samples, many of which could be quantified in the whole coal analysis. Several mineral species at levels of 5 weightpercent or less were observed only in the ashed scans. Some dehydration and reconstitution reactions were observed in the ashing process, including the combination of organically bound alkaline-earth elements and sulfur to form bassanite and magnesium sulfates. Quartz and kaolinite dominated the silicate mineral portion of the mineralogy, whereas calcite and siderite represented the carbonate; pyrite with associated sulfate oxidation products were generally present as well. The X-ray transmission studies were successful in estimating the carbonaceous matter in the whole coal samples and comparison of the chemical oxides derived from the X-ray data with direct analyses from the Penn State data sheets revealed good correlations, although significant departures occurred for some species and a systematic underestimation of aluminum oxide from the X-ray clay peaks was observed. This study suggests that the RIM procedure can be applied to coal mineral and amorphous component analysis on a routine basis.

Twenty seven new rare earth (Ln) compounds CuLn2 Ge2O8, CuLn2Ge4O12 and CuLn2Si4O12 have been synthesized. The powder diagrams were indexed and solid solutions of silicates and germanates were investigated. Structural variations with temperature, lanthanide contraction and Ge/Si substitution are described. Indications for second order phase transitions were found.

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 neodymium hydroxynitrate, Nd(OH)2(NO3).H2O, (PDF #37-1841) has been investigated by means of X-ray powder diffraction data. The unit cell dimensions were determined from diffractometer methods, using strictly monochromatized CuKα1 radiation, and evaluated by indexing programs. The monoclinic cell found was a = 19.381(4)Å, b = 3.884(1)Å, c = 6.291(1)Å, β = 96.43(2)°.

The following new or updated patterns are submitted by the JCPDS Research Associateship at the National Bureau of Standards. The patterns are a continuation of the series of standard X-ray diffraction powder patterns published previously in the NBS Circular 539, the NBS Monograph 25, and in this journal. The methods of producing these reference patterns are described in this journal, Vol. 1, No. 1, p. 40 (1986).

The data for each phase apply to the specific sample described. A sample was mixed with one or two internal standards: silicon (SRM640a), silver, tungsten, or fluorophlogopite (SRM675). Expected 2-theta values for these standards are specified in the methods described (ibid.). Data, from which the reported 2-theta values were determined, were measured with a computer controlled diffractometer. Computer programs were used to locate peak positions and calibrate the patterns as well as to perform variable indexing and least squares cell refinement.