Heavy atoms dominate the X-ray scattering from many inorganic compounds like oxides and oxalates, and often only partial structures of these compounds can be obtained by X-ray powder diffraction data. Combining information from X-ray and neutron diffraction data is an advantage. Scattering contributions from the atoms are more evenly distributed in neutron diffraction data than in X-ray diffraction data. Neutron diffraction data can then be used to complete a structure partially solved with data from an X-ray diffraction pattern. Examples of heavy atom structures solved in the time period 1983–2004 using direct methods outlined above are presented.

The laboratory implementation of grazing incidence in-plane X-ray diffraction, using an unmodified commercial diffractometer, is described. Low resolution, high intensity measurements are illustrated in the study of the in-plane lattice parameters and texture of a thin polycrystalline ZnO film on glass, the in-plane order in Cd arachidate Langmuir–Blodgett films, and the depth dependence of the lattice parameter in graded Si–Ge epilayers. Use of an asymmetrically cut Ge crystal to compress and monochromate the beam provides a high resolution setting, appropriate to measurement of the in-plane mosaic of mismatched epilayers such as GaN on sapphire.

The crystal structures of Sr2MgWO6 and Ba2SrWO6 compounds, studied by powder X-ray diffraction, were found to be distorted perovskites with a complete NaCl type ordering between Mg2+/W6+ and Sr2+/W6+ ions, respectively. The unit cells are characterized by the tetragonal (space group I4/m; a0a0a−) symmetry, with the parameters a=5.5849(10) Å and c=7.9455(10) Å, for Sr2MgWO6 and triclinic (space group F-1; a−b−b−) symmetry, with the parameters a=8.5409(10) Å, b=c=8.5860(10) Å, α=89.35(1)° and β=γ=90.31(1)°, for Ba2SrWO6. © 2004 International Centre for Diffraction Data.

A neutron powder diffraction study on the crystal structure of the title compound (p-Br–C6D4–CD2–OD) confirmed that a first-order phase transition at Tt1=229 K accompanied a drastic change in the molecular conformation caused by a discontinuous rotational shift of the hydroxyl hydrogen atom around the C(D2)–O(D) bond. At T<Tt1, a contraction of the unit cell volume of ∼1% was found when compared to that of the normal compound (p-Br–C6H4–CH2–OH).

A new method is introduced for the evaluation of experimental stress–strain dependence in thermally cycled thin films. The method is demonstrated on the analysis of an Al thin film on a Si(100) substrate characterized using in situ high-temperature X-ray diffraction 25–450 °C. Diffraction data are used to evaluate in-plane elastic strain in the film as a function of thermal strain originating from the mismatch of thermal expansion coefficients (TECs) between the film and the substrate. The magnitude of the thermal strain is calculated from experimental TECs of the film and the substrate at every measurement temperature. By relating in-plane stresses to thermal strains, an experimental stress–strain dependence for the Al thin film is obtained. The proposed method allows one to identify elastic behavior and to quantify plastic strain in the film. Finally, advantages of the method are discussed in particular its independence from using TECs reported in the literature.

This study is about the structural properties of SiGe and SiGe:C heteroepitaxial layers on Si (001). The structural characterization is based on the application of complementary information content of X-ray scattering techniques like high-resolution X-ray diffraction (XRD), X-ray reflectivity (XRR), and X-ray diffuse scattering (XDS). One main focus of the analysis is to derive a sample model that sufficiently describes all experimental datasets. In addition, the reliability of parameters extracted by just one single method is discussed. It turned out that XRR is more sensitive to the near surface region, indicating the presence of surface roughness and density gradients that do not significantly affect the XRD pattern.

The crystal structure of several compounds of Ca1−xSrxZr4(PO4)6 ceramics has been investigated by X-ray powder diffraction at room temperature. All compounds form a solid solution with a unique unit cell. While the lattice parameter a of the hexagonal unit cell decreases of about 0.9% with increasing Sr content only slightly, it considerably elongates in c direction (2.8%). No structural transformation has been observed by high-temperature X-ray diffraction up to 1000 °C.

The crystal structures of some nickel hexacyanoferrates (II, III), including mixed compositions containing Na+, K+ and Cs+, were resolved and refined from XRD powder patterns. Data from infrared, Mössbauer and adsorption techniques provided complementary structural information. The crystal structures of Ni3[Fe(CN)6]2⋅16H2O and NiCs2[Fe(CN)6] were refined in space group Fm3m. NiNa2[Fe(CN)6]⋅2H2O and NiK2[Fe(CN)6]⋅2H2O were found to be orthorhombic (space group Pmn21). This structure (Pmn21) results from a distortion around the alkali ion, which appears as a monohydrated interstitial species. On ionic exchange in an aqueous solution containing Cs+, the orthorhombic distortion disappears and the cubic cell is obtained. Cs+ is a large cation and space is not available for interstitial water molecules. This orthorhombic model is also supported by the Mössbauer spectra of the ferrous analogs, FeK2[Fe(CN)6]⋅xH2O and Fe[Pt(CN)6]. © 2004 International Centre for Diffraction Data.

AFeTi(PO4)3 (A=Ca,Cd) materials were obtained by solid state reaction in air at 1000 °C. Structures of the two compounds were determined from X-ray diffraction data using Rietveld analysis. Both phases exhibit the Nasicon-type structure (R3¯c space group) with a statistical Fe(Ti) distribution within the framework. Their hexagonal cell parameters are a=8.518(1) Å, c=21.797(2) Å and a=8.534(1) Å, c=21.416(2) Å, for CaFeTi(PO4)3 and CdFeTi(PO4)3, respectively. Cd atoms occupy the M1 site in CdFeTi(PO4)3. From XRD data, it is difficult to distinguish without ambiguity between Ca2+ and Ti4+ ions in CaFeTi(PO4)3. Nevertheless from the cation–anion distance found after the structure determination, Ca2+ distribution within the M1 site of Nasicon structure are validated.

The X-ray powder diffraction patterns of three phenol derivatives—2-chlorophenol, 2,6-dichloro-4-nitrophenol, and 2,6-dichloro-phenoloindophenol tetrahydrate—were collected and the lattice parameters of these compounds were determined. The measurement for 2-chlorophenol was carried out at 250 K in a low-temperature chamber; this compound crystallizes in hexagonal system with a=1.59602(8) nm, c=0.59761(7) nm, space group P6 or P63/m. Investigated at room temperature, 2,6-dichloro-4-nitrophenol and 2,6-dichloro-phenoloindophenol tetrahydrate crystallize in the triclinic system with the unit cell parameters refined to a=0.8169(2) nm, b=1.6637(6) nm, c=0.7440(1) nm, α=96.6(3)°, β=116.19(2)°, γ=78.68°, and space group P-1(2), and a=0.7792(3) nm, b=1.2795(4) nm, c=0.7256(3) nm, α=91.17(5)°, β=96.93(4)°, γ=85.41(3)°, and space group P-1(2), respectively. © 2004 International Centre for Diffraction Data.

X-ray power diffraction data for CrFe3NiSn5 are reported. Indexing the XRD power pattern and Rietveld refinement shows that the compound crystallizes in the hexagonal crystal system, space group P6mm (No. 183) with lattice parameters a=5.3168(1) Å, c=4.4261(1) Å, z=0.6 and Dcalc=8.011 g cm−3. The crystal structure of CrFe3NiSn5 is of the CoSn structure type with Fe, Cr and Ni disordered in the Co position.

Local layer structures and their formation process in a half-V-shaped switching ferroelectric liquid crystal (HV-FLC) were investigated by means of synchrotron X-ray microdiffraction. The HV-FLC is a FLC that has a cholesteric–chiral smectic C (Ch–SmC*) phase transition sequences. X-ray microdiffraction measurements revealed that the SmC* phase in the HV-FLC was composed of asymmetric chevron and inclined-bookshelf structures. In addition, temperature-controlled X-ray diffraction measurements showed that the transient layer structures appeared during the Ch to SmC* phase transition.

Na4CrNi(PO4)3 orthophosphate powder was prepared from acid solutions of NiO, Na2CO3 and aqueous solutions of Cr(NO3)3.9H2O, and (NH4)2HPO4 at a final temperature of 750 °C. The hexagonal unit cell parameters were determined to be ah≈8.789 Å and ch≈21.481 Å in space group R3¯c. These parameters were compared to those of Na4AA′(PO4)3 (AA′=CrMg, CrCo, TiNa, ZrNa). The linear variations of these parameters versus the mean A cation radius (rAA′) are consistent with the atomic distribution found for the structure of Na4NiCr(PO4)3. The ah and ch parameters are functions of the An+ ion size.

The local variation in strain and rotation of the Si substrate due to overlying Ni thin film features has been observed using X-ray microdiffraction. Residual tensile stress in 1 μm thick, 190 μm diameter Ni dots of 990 MPa imparted an average compressive stress in the underlying Si substrate. Ni Kα fluorescence scans, acquired simultaneously with Si (333) diffraction data, allow for a precise determination of the Ni feature edge location relative to the observed shift in Si (333) peak position. Rocking curve mesh scans, in which the sample was translated perpendicular and parallel to the diffraction plane, were used to deconvolute the effects of substrate strain due to d-spacing shifts and rotation of the local Si surface. In addition, shear strains at the dot edge imparted a significant shift in the Si (333) diffraction peak, producing a secondary diffraction peak in modified reciprocal space scans.

Methods of chemical preparation and crystallographic data are reported for two new condensed phosphates: a polyphosphate of nickel and cesium, NiCs4(PO3)6, and a cyclotriphosphate of nickel and potassium, NiK4(P3O9)2. NiCs4(PO3)6 is rhombohedral with the following unit-cell dimensions: a=b=11.602(1) Å, c=9.078(1) Å, space group P−31c, V=1058.24(1) Å3, and Z=2. NiK4(P3O9)2 is triclinic with the following unit-cell dimensions: a=6.143(8) Å, b=6.80(1) Å, c=12.80(3) Å, α=102.8(3)°, β=89.7(2)°, γ=66.03(7)°, space group P−1, V=473.56(3) Å3, and Z=1.

The X-ray powder diffraction patterns for three two-component molecular crystals composed of 4-chloroanilinium and chloronitrobenzoic acids with different substituted positions are reported and discussed. © 2004 International Centre for Diffraction Data.

Diffraction of high-energy synchrotron radiation with wavelengths in the range of 0.1 Å, provided by the beamline BW5 at HASYLAB in Hamburg, was used to measure textures (orientation distribution) and microstructures (spatial distribution) of the crystallites in various polycrystalline materials. In order to achieve extremely high angular-combined with very high lateral resolution a continuous sweeping technique with an area detector was employed. This technique “images” three different types of two-dimensional sections and projections of the six-dimensional orientation–location space onto the area detector. In many cases the orientations and locations of all individual grains of the sample can thus be seen simultaneously. The high penetration depth of this radiation in the range of several centimeters (comparable with that of neutrons) allows investigating big or capsulated samples. Examples are given of grain-resolved recrystallization textures, a soldering seam, a filled beverage can, and the orientation distribution of kamacite lamellae in an iron meteorite, elucidating the orientation relationship of the γ→α transformation in iron.

Four manganese carbonyl complexes: CpMn(CO)3 (1) and its phenylvinylidene derivatives Cp(CO)2Mn=C=CHPh (2), [Cp(CO)2Mn]2(μ-C=CHPh) (3), and Cp(CO)2Mn=C=C(Ph)–C(Ph)=C=Mn(CO)2Cp (4) have been studied by X-ray powder diffraction and their unit cell parameters are reported. The monoclinic cell parameters found for complex (1) are a=12.0479(7) Å, b=7.0614(5) Å, c=10.9172(6) Å, β=117.626(2)°, Z=4, space group P2(1)/a (No. 14). The orthorhombic cells parameters for complex (2) are a=10.5240(12) Å, b=33.1105(48) Å, c=7.5007(9) Å, Z=8, space group PCCN (No. 56); for complex (3) are a=15.3545(17) Å, b=15.3966(18) Å, c=8.0033(7) Å, Z=4, space group P21212121 (No. 19). The parameters found for complexes (1–3) are in good agreement with those obtained from single crystal X-ray diffractometry. The single crystal structure of complex (4) has not been studied. The orthorhombic cell parameters for complex (4) found by X-ray powder diffraction method are a=10.0986(9) Å, b=33.2937(27) Å, c=7.4139(5) Å, Z=4, space group P21 (No. 4).

The X-ray diffraction patterns of two organic acids 1-naphthalenesulfonic acid dihydrate and 2-naphthalenesulfonic acid hydrate were measured at room temperature. Complexes of these acids with 1,8-bis(dimethylamino)naphthalene (DMAN) were synthesized, purified and investigated by means of X-ray powder diffraction. 1-Naphthalenesulfonic acid dihydrate as well as its complex with 1,8-bis(dimethylamino)naphthalene crystallize in the monoclinic system with unit cell parameters refined to a=0.91531(8) nm, b=0.7919(1) nm, c=0.8184(1) nm, β=101.618(9)° space group P21/m (11) and a=1.7781(4) nm, b=2.0122(4) nm, c=1.2337(2) nm, β=96.54(3)°, space group C2/m (12), respectively. 2-Naphthalenesulfonic acid hydrate crystallizes in the orthorhombic system with a=2.2749(3) nm, b=0.7745(1) nm, c=0.591 36(9) nm, space group Pnma, whereas its complex with 1,8-bis(dimethylamino)naphthalene crystallizes in the triclinic system a=1.3969(6) nm, b=1.4292(5) nm, c=1.1741(6) nm, α=90.93(3)°, β=98.14(3)°, γ=113.93(3)°, space group P-1 (2).