Two derivatives of 4-chloro-2,2′-iminodibenzoic acid: diethyl 4-chloro-2,2′-iminodibenzoate, C18H18ClNO4, and dimethyl 4-chloro-2,2′-iminodibenzoate C16H14ClNO4, have been investigated by means of X-ray powder diffraction. The unit cell dimensions were determined from diffractometer methods, using monochromatic CuKα1 radiation, and evaluated by indexing programs. The monoclinic cell found for diethyl 4-chloro-2,2′-iminodibenzoate was a=21.332(3) Å, b=7.889(2) Å, c=10.156(2) Å, β=91.43(1)°, Z=4, space group P2 (No. 3), Pm (No. 6), or P2/m (No. 10), Dx=1.351 mg/m3. The cell found for this compound is in good agreement with the one obtained from single crystal X-ray diffractometry. The monoclinic cell found for dimethyl 4-chloro-2,2′-iminodibenzoate has the dimensions a=15.962(2) Å, b=5.151(2) Å, c=12.590(2) Å, β=98.35(1)°. Z=4, space group P2 (No. 3), Pm (No. 6), or P2/m (No. 10), Dx=2.073 mg/m3.

The mathematical relationships are developed which are pertinent to the quantitative analysis of powder mixtures for the case of diffraction from the surface of a flat powder specimen. These formulas relate the diffracted intensity to the absorptive properties of the sample. Three important cases are treated: (1) Mixture of n components; absorbing powder of the unknown equal to that of the matrix; concentration proportional to intensity. Direct analysis is permitted. (2) Binary mixture; absorbing powder of the unknown not equal to that of the diluent; concentration not proportional to intensity. Direct analysis is possible by means of calibration curves prepared from synthetic mixtures. (3) Mixture of n components; absorbing power of the unknown not equal to that of the matrix; general case. Analysis is accomplished by the addition of an internal standard. Concentration is proportional to the ratio of the intensity of a selected reflection from the unknown to the intensity of a reflection from the internal standard.

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. A check on the overall internal consistency of the data was also provided by a computer program.

The indexed X-ray diffraction powder data of trans-bis(dimethylphenylphosphine)bis(pyrazole)platinum, {Pt(C3H4N2)2[P(CH3)2(C6H5)]2, PTPP} and trans-(tricyclohexylphosphino) (triethylphosphino) platinum(II) chloride, (PtCl2P2C24H48, PTHE) are reported. PTPP crystallizes in the monoclinic space group C2/c and PTHE crystallizes in the orthorhombic space group Pcab. The refined cell parameters were determined by employing a Siemens Debye-Scherrer camera (Fe radiation, λmean = 1.93736 Å). The cell constants are a = 21.516(5), b = 6.287(1), c = 17.929(4)Å, β = 102.51(1)°, V = 2367.7Å3 Dx=1.70Mg m−3, Dm = 1.70Mg m−3 for PTPP and a = 12.271(1), b = 19.375(1), c = 23.864(3)Å, V = 5673.4Å3, Dx = 1.553Mg m−3 for PTHE. The quantitative figures of merit (FN) are F23 = 47(0.010,51) [F20 = 60(0.009,35)] for PTPP and F30 = 12(0.008,324) [F20 = 27(0.017,105)] for PTHE. The JCPD S Diffraction File No. for PTPP is 37-1999 and for PTHE is 37-2000.

The error is investigated which results from the employment of tangential approximation in the calculation of line shift caused by specimen displacement from the recording circle in focusing systems (Guinier, Seemann–Bohlin). After an exact expression has been deduced and compared with the approximate formula in a numerical example, it is concluded that the error caused by the approximate formula may be important only in exceptional cases. The deduced exact formula is also compared with that given by Rafaja and Valvoda [Powder Diffr. 6, 200–203 (1991)] with the conclusion that both formulas are mathematically equivalent and complementary with respect to the theoretical and measured values of the diffraction angle 2θ.

The X-ray powder diffraction patterns for tetramethylammonium bromide and iodide have been measured from near room temperature up to decomposition/sublimation. The unit cell parameters were refined and the coefficients of thermal expansion calculated. Unlike N(CH3)4Cl [M. Stammler, J. Inorg. Nucl. Chem. 29, 2203–2221 (1967)], N(CH3)4Br (1Br) and N(CH3)4I (1I) undergo no solid–solid transitions before decomposition/sublimation as was observed earlier by thermal analysis [S. S. Chang and E. F. Westrum, J. Chem. Phys. 36(9), 2420–2423 (1962); Coulter etal., J. Am. Chem. Soc. 62, 2845–2851 (1940); Xenopoulos etal., Mol. Cryst. Liq. Cryst. 214, 63–79 (1992)].

Powder X-ray diffraction was used to investigate the solid solution range of the Bi14SrxCa12−xO33 series in the Bi–Sr–Ca–O system. Solid solution forms over the range 1≤x≤7 in Bi14SrxCa12−xO33. Experimental X-ray reference patterns of selected members with x=1, 3, 5, and 7 have been prepared for the powder diffraction file (PDF). These phases are monoclinic, C2/m, with cell parameter a ranging from 21.473(4) to 21.868(4) Å, b from 4.3564(9) to 4.3898(9) Å, c from 12.753(2) to 12.962(2) Å, β from 102.91(2)° to 102.79(1)°, and V from 1162.9(3) to 1213.5(3) Å3, respectively. These parameters increase monotonically as Ca is continuously replaced by the larger Sr.

The X-ray powder diffraction pattern for the title compound is reported in the range 5 ≤ 2θ ≤ 125°. The sample was prepared through solid-state reaction of BaCO3, CuO, and Pr6O11, and characterized with respect to oxygen content through iodometric titration. Refined parameters for the orthorhombic (space group Pmmm) unit cell are a = 3.8587(2) Å; b = 3.9302(1) Å; c= 11.7126(3) Å; a/b = 0.98181(6); a/c = 0.32945(2); b/c = 0.33555(1); Z = 1; Dx = 6.705(2) Mg m−3; V = 177.62(1) Å3; formula wt. = 717.48(16) g mol−1; SS/FOM: F30 = 48(0.005,127).

The crystal structure of [Pd(NH3)4]C2O4 was determined from X-ray powder data. The crystals are triclinic with unit-cell parameters: a=7.0807(7) Å, b=7.0806(7) Å, c=3.8011(5) Å, α=91.910(1)°, β=98.665(1)°, γ=97.283(1)°, S.G.=P−1, Z=1, V=187.11 Å3. All non-hydrogen atoms were located from the Patterson map. The structure was refined by the Rietveld technique: Rp−b=6.88, Rwp=6.51, RB=2.66. The crystal structure of [Pd(NH3)4]C2O4 is built from two types of elements: [Pd(NH3)4]2+ and C2O2−4. Cations [Pd(NH3)4]2+ form columns along c with distances (Pd–Pd)=3.8011 Å. C2O2−4 anions occupy places in the middle of the unit cell between layers of [Pd(NH3)4]2+. The compound is stable up to 200 °C and then decomposes, giving Pd powder.

CuInSeTe was synthesized by the melt and anneal technique. The compound crystallized in the chalcopyrite structure having space group I4¯2d with Z=4. Complete X-ray powder diffraction data were obtained and the unit cell parameters a and c, X-ray density and u parameter were calculated. These are a=0.5987(1) nm, c=1.1979(4) nm, Dx=5.96×103kg/m3, and u=0.2498. Atomic positions in the unit cell are proposed.© 2000 International Centre for Diffraction Data.

A quantitative phase analysis often requires advanced numerical studies to determine the appropriate intensity values. In this paper the method of fitting analytical functions to the experimental profile is applied to X-ray powder diffraction patterns obtained with FeK radiation. In the present work, the authors examine some problems connected with numerical studies, especially the function describing the experimental profile. The usefulness of the α2 elimination procedure and the angular dependence FWHM are also examined.

The X-ray diffraction data for the single phase UAl4 are reported. The data were obtained with a Huber–Guinier diffractometer with MoKα1 radiation. The unit cell of UAl4 is orthorhombic (space group Imma) with lattice parameters a=4.396 Å, b=6.251 Å, and c=13.699 Å.

X-ray powder diffraction was used as an analytical technique for the solid state synthesis of selective oxidation catalysts with large surface area. Qualitative analysis was used to determine the minimum temperature at which the synthesis was complete. Quantitative diffraction was used to analyze mixtures of isomorphous antimonates. Results indicated that the final mixtures are independent of the method of preparation, i.e., mixing or impregnation.

High temperature superconducting phases in the Tl-Ca-Ba-Cu-O system are ideally represented by the formula TlmCan−1Ba2CunO2(n+1)+m, with m either 1 or 2 and n = 1 to at least 3 (Parkin et at., 1988). Each of these phases contains one or more of the nearly planar CuO2sheets common to the cuprate superconductors. A single Ca atom separates adjacent CuO2sheets (n > 1). Single or double rock salt-like Tl-O layers are separated from the Can−1CunO2nregions by single Ba-O layers. Each of the Ca-containing members of this family crystallizes in a tetgragonal unit cell, with space group 14/mmm for the m = 2 series and P4/mmm for the m = 1 series.

Despite the general interest in this family of superconductors, little has been reported about the m = 1, n = 2 member, TlCaBa2Cu2O7−δ, hereafter called 1122. This lack of work is due at least in part to the difficulty in synthesizing the pure compound (Michel et at., 1991). Additionally, technological interest has focused on members of the family with higher superconducting transition temperatures, particularly Tl2Ca2Ba2Cu3Oywith Tcup to 125 K. The critical temperature of 1122 has been reported from as low as 50 K (Hervieu et al., 1988) to as high as 103 K (Morosin et al., 1988), and at several values in between (Ganguli et al., 1988; Liang et al., 1988). Most of the samples had other superconducting phases in addition to 1122. Because of the nearly identical a axis lengths of the unit cells of the Tl-family of superconductors, syntactic intergrowths may be present in such multiphase samples.