The Reference Intensity Ratio (RIR) is a general, instrument-independent constant for use in quantitative phase analysis by the X-ray powder diffraction internal standard method. When the reference standard is corundum, RIR is known as I/Ic; These constants are collected in the Powder Diffraction File (1987), can be calculated, and can be measured. Recommended methods for accurate measurement of RIR constants are presented, and methods of using these constants for quantitative analysis are discussed. The numerous, complex constants in Copeland and Bragg's method introduced to account for superimposed lines can be simply expressed in terms of RIR constants and relative intensities. This formalism also permits introduction of constraints and supplemental equations based on elemental analysis.

A nonlinear optical material 4-(N,N-dimethylamino)-3-acetamidonitrobenzene, (CH3)2NC6H3NO2NHCOCH3, has been characterized by X-ray powder diffractometer method. The experimental 2θ values corrected for systematic errors, the relative intensities, values of dexp and the Miller indices of the 46 peaks observed in the 5° to 51° 2θ range are reported. The powder diffraction data have been evaluated, and the figure of merit is F30 = 36.6 (0.016, 51). The unit cell parameter least-squares refined from 38 non-overlapping peaks of the monoclinic compound with a P21 space group are: a = 4.792(1)Å, b = 13.055(2)Å, c = 8.735(1)Å, β = 94.43(2)°, V = 544.8(1)Å3, Z = 2, and Dx = 1.36 gm/cm3. The powder diffraction results are in a good agreement with those obtained from single-crystal structure data.

An ordered oxygen-deficient tetragonal perovskite compound La1.67Sr0.33Cu205 has been synthesized by solid state reaction. X-ray powder diffraction was used to characterize the material. Unit cell parameters least-squares refined from non-overlapping diffraction peaks are a = 10.8696(9)Å, c = 3.8612(6)Å and V = 456.2(1)Å3. X-ray powder data have been obtained for the experimentally observed peak positions corrected for systematic errors, the relative intensities, values of dexp and the Miller indices of both resolved and overlapping reflections. The experimental diffraction pattern was compared to computer simulated patterns calculated from the neutron crystal structure parameters and the non-oxygen-deficient LaCuO3 compound. The figure of merit is F30 = 33.8 (0.018, 48).

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).

A quantitative simultaneous determination method by X-ray powder diffractometry is described for calcium sulfate and calcium carbonate in airborne dusts. In order to eliminate the mutual interference among diffraction peaks, and to avoid the presence of the hydration isomers of calcium sulfate, dust samples were heated at 350°C for 2 h. To reduce the errors due to the difference-in crystallinity between the standard materials and the samples, the synthesized calcium sulfate anhydrate (anhydrite) was heated to such an extent that the half-width of the 002,020 peak was identical with that of the anhydrite in pretreated dust samples. Standard calcium carbonate (calcite) was ground until the half-width and the orientation index of the 104 peak of calcite was identical with that of the calcite in dust samples. Linear calibration curves were obtained throughout the range of 0 ∼ 30 wt% for anhydrite and the range of 0 ∼ 10 wt% for calcite, respectively. The determination limits were 0.2 wt% for anhydrite and 0.3 wt% for calcite. Relative standard deviations were 3.4 % for 8.0 wt% of anhydrite and 1.8% for 5.4 wt% of calcite. The present method is applicable to determination of calcium sulfate and calcium carbonate in actual dust samples.

A conventional Bragg-Brentano type diffractometer was equipped with a stepping motor, a timer, and a scaler, and an MC68000 Motorola microprocessor which controls the diffractometer functions. The microprocessor was programmed to operate the diffractometer in a step-scanning mode, to check a datum and to communicate with a process control computer, e.g. a PDP 11/44 or a Micro VaxII computer.

Bright apple green millimeter-sized crystals of tavorite from the Tip Top pegmatite, near Custer, South Dakota are triclinic, space group , with refined unit-cell parameters a = 5.340(2), b = 7.283(2), c = 5.110(2)Å, α = 109.29(2)°, β = 97.86(3)°, γ = 106.32(3)°, V = 174.1(3)Å3, a:b:c = 0.7332:1:0.7016, Z = 2, D(m) (suspension in methylene iodide) = 3.32(1) and D(x) = 3.33 g/cm3 (for the theoretical formula). A fully indexed X-ray powder pattern is presented. Semiquantitative electron microprobe and secondary ion mass spectroscopic analyses indicate a formula near end-member LiFe + 3(PO4)(OH). The Tip Top tavorite is biaxial positive, α = 1.795(5), β = 1.81(1), γ = 1.86(1), 2V(meas.) = 50(2)°, 2V(calc.) = 59°, XΛa ≃ 15°, YΛb ≃ 0°, and ZΛc ≃ 38°. There is no evidence for optical absorption, pleochroism or dispersion.

The trihydrated ammonium trioxalato-ferrate (III) (NH4)3(Fe(C2O4)3)·3H2O cristallizes in the monoclinic system with:

The space group is P21/c[14].

X-ray powder data and crystal data for the ortho (2 –), meta (3 – ) and para (4 – ) isomers of nitroaniline, NO2C6H4NH2, are reported. The results are compared to existing PDF patterns.

X-ray powder data and crystal data for acetaminophen, C8H9NO2, are reported and results are compared to existing PDF patterns.

X-ray powder data for a maghemite (γ-Fe2O3) used for computer hard disks is reported. This maghemite is cubic with space group P4132.

Seven isotopic molybdates MIIUMo4O16 have been synthesized by solid state reaction with MII = Mg, Mn, Cd, Ca, Hg, Sr, Pb. Single crystals of CaUMo4O16 were obtained. Previously reported as triclinic, this compound is monoclinic, space group P2/n. Unit-cell parameters for the seven compounds are:

MgUMo4O16: a = 11.393(2), b = 6.505(1), c = 7.918(2) Å, β = 89.81(3)°, V = 586.8(5) Å3, Z = 2, Dx = 5.12 Mg m−3;

MnUMo4O16: a = 11.413(2), b = 6.555(1), c = 8.023(1) Å, β = 89.86(2)°, V = 600.2(4)Å3, Z = 2, Dx = 5.18 Mg m−3;

CdUMo4O16: a = 11.427(2), b = 6.607(1), c = 8.144(2) Å3, β = 90.40(2)°, V = 614.8(5)Å3, Z = 2, Dx = 5.37 Mg m−3;

CaUMo4O16: a = 11.443(3), b = 6.653(2), c = 8.239(2)Å, β = 90.51(3)°, V = 627.2(6)Å3, Z = 2, Dm = 4.83(5), Dx = 4.88 Mg m−3;

HgUMo4O16: a = 11.439(3), b = 6.643(1), c = 8.257(2)Å, β = 90.53(3)°, V = 627.4(6)Å3, Z = 2, Dx = 5.73 Mg m−3;

SrUMo4O16: 11.465(3), b = 6.768(2), c = 8.492(2) Å, β = 90.86(3)°, V = 658.8(6)Å3, Z = 2, Dx = 4.88 Mg m−3;

PbUMo4O16: a = 11.470(4), b = 6.813(2), c = 8.557(2)Å, β = 90.88(4)°, V = 668.7(8)Å3, Dx = 5.41 Mg m−3;

Powder diffraction data for each phase are reported.

Neodymium ammonium hydroxynitrate, Nd(OH)2NO3.(NH4NO3)0.5.H2O, has been investigated by means of X-ray powder diffraction. Unit cell dimensions were determined by indexing programs, from diffractometer data obtained with strictly monochromatic CuKα1 radiation. An I orthorhombic cell was found: a = 24.577 (4) Å, b = 7.1488 (16) Å, c = 3.8211 (9) Å. It is shown that the h 1 1 reflections present a selective line broadening.

The following fourteen reference patterns of carbide, nitride, telluride, and oxide ceramics are reported. Included in the fourteen reference patterns are data for three high Tc superconducting oxide related phases (Ba2CuO3, CuSrO2, and Ba2Cu3YO6). The general methods of producing these X-ray powder diffraction reference patterns are described in this journal, Vol. 1, No. 1, pg. 40 (1986).

Samples were mixed with one or two internal standards: silicon (SRM640a), silver, tungsten, or fluorophlogopite (SRM675). Expected 2θ values for these internal standards are specified in the methods described (ibid.). Data were measured with a computer controlled diffractometer. The POWDER-PATTERN system of computer programs was used to locate peak positions, to calibrate the patterns, and 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.