As a producer of certified reference materials (CRMs), NIST faces high demand for Standard Reference Materials (SRMs). The demand is exacerbated by widespread misuse of CRMs. When should one use CRMs? When should one not use CRMs? Must labs always use NIST SRMs? How can labs demonstrate analytical capabilities for their accreditation scopes? Why so many questions? Standards developers, laboratory accreditors, and laboratory staff must be able to understand these topics with respect to quality systems in compliance with ISO/IEC 17025. They must calibrate and validate test methods and document traceability to the International System of Units (SI). Many people working in laboratory accreditation and under the umbrella of a quality system do not fully understand what these things are, let alone the language of chemical metrology. On average, they have little training in analytical chemistry, elemental analysis, and reference material development. It is hoped this paper will impress upon the reader the need for understanding how CRMs can be best used in the laboratory. This paper provides a brief background on the above problems and then looks at some of the support and reference information provided by NIST to metals and mining industries labs, commercial CRM producers, and accrediting bodies. The concepts and guidance apply broadly to chemical metrology and fundamental analytical chemistry. The paper includes examples (some from X-ray fluorescence spectrometry) to illustrate concepts.

A combination of neutron diffraction, synchrotron X-ray diffraction, and high-resolution extended X-ray absorption fine structure measurements has been used to clarify the correlations between long- and local-range structural distortions across the spin-state transition in powders of LaCoO3 and La0.5Sr0.5Co0.75Nb0.25O3. The analysis of the diffraction data has revealed that the isotropic thermal parameters of Co–O bond abnormally increase below 100 K in both samples, while the temperature dependence of the average Co–O bond lengths is linear from 10 to 300 K. We also have found that the Co–O bond lengths are larger in La0.5Sr0.5Co0.75Nb0.25O3, as compared with the ones in LaCoO3. The X-ray absorption data showed an anomalous decrease of the Co–O bond lengths only for LaCoO3, in contrast to the bond length values obtained by diffraction. The structural anomalies observed by spectroscopy measurements are discussed in terms of the spin-state transition model.

Powder diffraction data are presented for 3,4-methylenedioxymethylamphetamine hydrochloride monohydrate, the hydrated form of MDMA.HCl, the drug of abuse commonly known as Ecstasy. Samples of pure MDMA.HCl were recrystallized from a variety of solvents, and powder diffraction patterns of the resulting products recorded. Data were collected at room temperature using iron-filtered CoKα radiation.

In an effort to better understand the structural changes occurring during hydrogen loading of erbium target materials, we have performed in situ D2 loading of erbium metal (powder) at temperature (450°C) with simultaneous neutron diffraction analysis. This experiment tracked the conversion of Er metal to the α erbium deuteride (solid-solution) phase and then into the β (fluorite) phase. Complete conversion to ErD2.0 was accomplished at 10 Torr D2 pressure with deuterium fully occupying the tetrahedral sites in the fluorite lattice.

Biaxial residual stress in a 〈111〉 textured cubic TiN polycrystalline thin film was analyzed by linear least-squares refinement using the method proposed by Yokoyama and Harada [J. Appl. Crystallogr. 42, 185–191 (2009)]. Values of the unstressed (or stress-free) unit-cell parameter a0=4.2332±0.0006 Å and the stress components of σ11=397(88), σ22=401(88), and σ12=−110(100) were obtained. The values of the in-plane stresses σ11 and σ22 presented in the TiN film are practically the same, while σ12 is relatively small. The results obtained in this study confirm that the above theoretical prediction by Yokoyama and Harada can be used to obtain reliable values of stress-free unit-cell parameter and three biaxial stress components of a textured cubic thin film.

X-ray diffraction and neutron spectra present a peak assembly whose maxima are centered at angles corresponding to Bragg's law.

Analysis of diffracted intensity profiles in each peak can be used to estimate such morphologic characteristics of the samples as preferred orientation (Brindley and Kurtosy, 1961; Martin, 1966); crystallite sizes (Scherrer, 1919; Warren and Averbach, 1950; Wilson, 1962; and Guérin et al., 1986); and crystal shapes (Wilson, 1949). Such analysis can also be used to estimate the determination of residual stress and lattice defects (Warren and Averbach, 1950; Wilson, 1963). In such studies, a detailed analysis of the diffraction distribution is required and consequently adjustment of intensity values must be carried out, as they are affected by systematic errors in the measuring apparatus (for detailed description, see Klug and Alexander, 1974 and Wilson 1967).

Ba2NaNb5,O15 and eighteen additional compositions in the NaNbO3-BaNb2O6 system from 60 to 85 mole % BaNb2O6 have been prepared and studied by X-ray powder diffraction. A calculated pattern has been used to aid in indexing the powder pattern of stoichiometric Ba2NaNb5O15(BNN-S). The lattice parameters of BNN-S have been determined from repeated measurements of 2 higher order reflections and are a=b=17.5994(8)Å and c=7.9771(9)Å. A comparison with the Powder Diffraction File (PDF) 34-210 indicates that the present data provide a more precise match to the unit cell, include additional weak reflections and cover a greater 2θ range. There is a tungsten bronzetype solid solution range from 60 to 75 mole % BaNb2O6.

The transition between tetragonal and cubic phases in nanostructured ZrO2-Sc2O3 solid solutions by high-temperature X-ray powder diffraction using synchrotron radiation is presented. ZrO2-8 and 11 mol% Sc2O3 nanopowders that exhibit the t′- and t″-forms of the tetragonal phase, respectively, were synthesized by a stoichiometric nitrate-lysine gel-combustion route. The average crystallite size treated at 900°C was about 25 nm for both compositions. Our results showed that t′-t″ and t″-cubic transitions take place for the 8 and 11 mol% Sc2O3 samples, respectively.

The ternary compound YAg0.4Ga1.6 has the CaIn2-type structure. The only variable positional parameter z was determined by graphical methods from visual observations of intensities on a Debye-Scherrer pattern. Cu or Ni substitutions for Ag also result in a ternary CaIn2-type structure.

A direct method for determining powder diffraction data from a range of depths is described, where the linear absorption coefficient may vary with depth. A series of traditional data collections with varying angles of incidence are required, and the X-ray diffraction data arising from specific depths will be calculated by the transformation of these measured, angle-dependent spectra. These may then be analysed using any conventional method in order to gain information about characteristics of the sample in question at specific depths. Regularisation techniques have been used to solve the governing Fredholm integral equation to determine the depth-dependent diffractograms. The method has been validated by the use of simulated data having known model profiles, and has also been applied to experimental data from polycrystalline thin film samples.

A set of nine transition metal oxophosphorous compounds, consisting of four hypophosphites and five phosphites has been synthesized and studied using X-ray powder diffraction techniques. The compounds are α-Mn(H2PO2)2·H2O, Co(H2PO2)2 ·0.53H2O, MCl(H2PO2)2·H2O (M = Co2+, Ni2+), M2(HPO3)2·2H2O (M = Co2+, Ni2+), and M11 (HPO3)8(OH)6 (M = Zn2+, Co2+, Ni2+). Unit cells and X-ray powder patterns are reported.

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.

X-ray powder diffraction data for the orthorhombic natural amino acid djenkolic acid, C7H14N2O4S2, is described in this paper. The orthorhombic cell parameters are: a=8.12 Å, b=12.16 Å, and c=5.38 Å

Cu2Th4(MoO4)9 is cubic: a=14.4856(1) Å, space group I4¯3d, Z=4. Its crystal structure was recently determined using a single crystal. The results of chemical study allow one to reject the existence of Li4Th7(MO4)16 and La(MO4)(ReO4) compounds with M=Mo, W, reported as isostructural with Cu2Th4(MoO4)9. Precise X-ray powder patterns are established for Cu2Th4(MoO4)9 and isotypic compounds Li2Th4(MoO4)9, Li2Th4(WO4)9, and La4(MoO4)3(ReO4)6.

The crystal structure of danofloxacin mesylate has been solved and refined using synchrotron X-ray powder diffraction data and optimized using density functional theory techniques. Danofloxacin mesylate crystallizes in space group P1 (#1) with a = 6.77474(8), b = 12.4973(4), c = 12.82826(28) Å, α = 84.8709(29), β = 87.7501(10), γ = 74.9916(4)°, V = 1044.723(11) Å3, and Z = 2. The protonation of the danofloxacin cations was established by the analysis of potential intermolecular interactions and differs from that expected from isolated-cation calculations. The crystal structure consists of alternating layers of cations and anions parallel to the ac-plane. There is parallel stacking of the oxoquinoline rings along the a-axis. The expected N–H⋯O hydrogen bonds between the cations and anions are not present. Each cation makes an N–H⋯O hydrogen bond with the other cation, resulting in zig-zag chains along the a-axis. Both cations have strong intramolecular O–H⋯O hydrogen bonds. There are several C–H⋯O hydrogen bonds between the danofloxacin cations and mesylate anions. The powder pattern has been submitted to ICDD® for inclusion in the Powder Diffraction File™ (PDF®).

The workshop was aimed at demonstrating the uses and methods of analysis of powder diffraction data collected from X-ray sources. There were around 35 participants in the workshop from Chile, Uruguay, Brazil, and Argentine. The participants came from inorganic and organic chemistry, physics, mineralogy and materials science backgrounds, and additionally we had attendees from a local cement company.