A new method is used in measuring the linear thermal expansion coefficients in composite consisting of a substrate Gd3Ga2Ga3O12 (GGG) and its epitaxial layer Y3Fe2Fe3O12 (YIG) within the temperature range 13.88 °C–32.50 °C. The results show that the thermal expansion coefficient of GGG in composite is larger than that of the GGG in single crystal; the thermal expansion coefficient of thick film YIG is also larger than that of thin film. The results also show that the thermal expansion coefficient of a composite consisting of film and its substrate can be measured by using a new method.

More than 10 000 inorganic structures based on both X-ray and neutron powder diffraction data were extracted from the ICSD database and analyzed considering overall trends, cell symmetries, occurrence of the space groups, complexity, precision and reliability of reported data. It was found that the major amount of structures belong to higher symmetries and have 2–5 atoms in the asymmetric unit. Less than 35% of the e.s.d.'s of atomic coordinates is ≤10−3 and 10−4 or better was reached in only 5% of cases. Approximately one-quarter of papers contain possibly inaccurate atomic coordinates or interatomic distances. A short review of journals publishing structures derived from powders is also given.

The structure of the oxyphosphate Ni0.50TiO(PO4) has been determined ab initio from conventional X-ray powder diffraction data by the “heavy atom” method. The cell is monoclinic (space group P21/c, Z=4) with a=7.3830(5) Å, b=7.3226(5) Å, c=7.3444(5) Å, and β=120.233(6)°. Refinement of 46 parameters by the Rietveld method, using 645 reflexions, leads to cRwp=0.152, cRp=0.120, and RB=0.043. The structure of Ni0.50TiO(PO4) can be described as a TiOPO4 framework constituted by chains of tilted corner-sharing TiO6 octahedra running parallel to the c axis, crosslinked by phosphate tetrahedra and in which one-half of octahedral cavities created are occupied by Ni atoms. Ti atoms are displaced from the center of octahedra units in alternating long (2.231) and short (1.703 Å) Ti–O bonds along chains.

FARHAN is a PC interactive, graphically oriented search–match–identification–quantification computer program for X-ray powder diffraction, which uses a variable intensity-error window (IEW). Both the intensity scale factor and the IEW for each standard phase are estimated by a simple iterative procedure. A new tunable combined figure-of-merit (agreement function) is suggested for estimating the goodness-of-fit of matches. The concentrations of the identified phases may be determined by normalized or generalized RIR quantification methods, if the RIRs of the identified phases are known.

Bafertisite, Ba(Fe, Mn)2Ti(Si2O7)O(OH, Cl)2, has been reported as belonging to three space groups, i.e., Pmmn, P21/m, and Cm. The samples of bafertisite from the original locality Bayan Obo, Inner Mongolia, and from Jiangsu Province, China, were reinvestigated by X-ray methods. On the basis of single-crystal photographs, Pmmn could be ruled out and the relationship between a subcell in P21/m and the true cell in Cm deduced. The transformation matrix from the subcell to the true cell is 002/02¯0/101¯. Using the X-ray powder data, the refined true unit cell parameters in space group Cm are: a=10.612(3), b=13.637(7), c=12.464(2) Å, β=119.49(2)° for Bayan Obo sample, and a=10.633(6), b=13.67(1), c=12.465(5) Å, β=119.55(4)° for the Jiangsu sample. The 00l-reflections, which are rather prominent due to preferred orientation, can only be explained by our new unit cell.

The crystal structure of four cyanometallates has been determined from X-ray powder diffraction data using the Rietveld method. The variously hydrated compounds Cu3[Co(CN)6]2, Mn3[Co(CN)6]2 and KNi[Fe(CN)6] crystallize at cubic symmetry (Fm3m) with lattice parameters 10.032(2), 10.413(3) and 10.234(5) Å, respectively. The crystal of KMn[Fe(CN)6]·2H2O shows a monoclinic structure (P21/c) with the lattice parameters a=10.108(2) Å, b=10.104(3) Å, c=10.114(3) Å, β=92°, 93°. The starting model was based on an isomorphic Mn3[Co(CN)6]2 single crystal structure, where Co and Mn ions are octahedrally coordinated by C and N atoms, respectively, forming three-dimensional bimetallic networks with the C≡N groups as bridging ligands.

Experimental X-ray powder diffraction patterns and refined unit cell parameters for two barium hollandite-type compounds, BaxFe2xTi8−2xO16, with x=1.143 and 1.333, are reported here. Compared to the tetragonal parent structure, both compounds exhibit monoclinic distortions that increase with Ba content [Ba1.333Fe2.666Ti5.334O16: a=10.2328(8), b=2.9777(4), c=9.899(1) Å, β=91.04(1)°, V=301.58(5) Å3, Z=1, ρcalc=4.64 g/cc; Ba1.143Fe2.286Ti5.714O16: a=10.1066(6), b=2.9690(3), c=10.064(2) Å, β=90.077(6)°, V=301.98(4) Å3, Z=1, ρcalc=4.48 g/cc]. The X-ray powder patterns for both phases contain a number of broad, weak superlattice peaks attributed to ordering of the Ba2+ ions within the tunnels of the hollandite framework structure. According to the criteria developed by Cheary and Squadrito [Acta Crystallogr. B 45, 205 (1989)], the observed positions of the (0k1)/(1k0) superlattice peaks are consistent with the nominal x-values of both compounds, and the k values calculated from the corresponding d-spacings suggest that the Ba ordering within the tunnels is commensurate for x=1.333 and incommensurate for x=1.143. High-temperature X-ray diffraction data indicate that the x=1.333 compound undergoes a monoclinic→tetragonal phase transition between 310 and 360 °C.

The structure type of La2Ti10.27Ga9.63O38 was revealed by a search-match using the PDF. A successful Rietveld refinement (Rp=8.9, Rwp=13.3, RB=4.20) confirmed the structure to be rhombohedral (space group R3¯, No. 148) with the refined unit cell parameters a=9.1878(1) Å, α=68.458(1)°, and V=646.374(1) Å3. The structure is compared to other compounds of the davidite type, and the observed and calculated powder data are given.

Powder diffraction data for 2-aminophenalenone at 295 K (P21/n, Z=4) are given, strong lines: 7.54/X, 7.26/9, 3.34/3. The cell parameters found are a=3.7213(3), b=16.550(2), c=15.095(2) Å, β=92.61(2)°. The crystal structure was determined using powder data and refined giving Rb=0.089. Disordered molecules form stacks along [100] with interplanar spacing of 3.48 Å.

The structure of K3H(SO4)2 is found to be monoclinic with space group C2/c based on analogy of the powder X-ray diffraction pattern with that of the Rb3H(SO4)2. The lattice parameters are a=14.6984(7), b=5.6840(2), c=9.7834(5) Å, and β=103.004(5)°, Vol=796.39(5); Dx=2.589 gcm−3, Z=4, and I/Icor=1.30.

X-ray powder data are given for cobalt tris-ethylenediamine bromide trihydrate, [Co(en)3]Br3·3H2O, and cobalt tris-ethylenediamine iodide hemihydrate, [Co(en)3]I3·0.5H2O. Refined unit-cell parameters for [Co(en)3]Br3·3H2O are a=11.6949(4) Å and c=16.0640(12) Å in trigonal space group P3¯c1(165) or P3c1(158); volume =1902.72 Å3; figures of merit: M20=29, F30=55 (0.0138, 40). Refined unit-cell parameters for [Co(en)3]I3·0.5H2O are a=23.3580(14) Å, b=13.4739(4) Å, and c=11.5421(5) Å in orthorhombic space group Pca21(29) or Pcam(57); volume =3632.57 Å3; figures of merit: M20=37, F30=81 (0.0058, 64).

The new diffraction patterns of the low- and high-temperature phases of Li0.87Hf2.032(PO4)3 and LiSn2(PO4)3 are given and indexed on the basis of a structure refinement from neutron powder data using Rietveld method. The two isotypic compounds present a reversible phase transition: triclinic (LT, space group P1¯) ⇄ rhombohedral (HT, space group R3¯c) which proceeds by topotactic distortion of the structural skeleton.

X-ray powder diffraction data for κ-Al2O3 are reported. It was concluded that κ-Al2O3 belongs to the orthorhombic crystal system with space group Pna21. The lattice parameters were found to be a=4.8351(3) Å, b=8.3109(5) Å, c=8.9363(3) Å. There are 16 Al3+ and 24 O2− in the unit cell, and thus the number of chemical formulas in the unit cell, Z, is 8. The volume V of the unit cell is equal to 359.09(6) Å3 and the theoretical density Dx is 3.772 g/cm3. The Smith–Snyder (F20) and the de Wolff (M20) values for these data are 136.1 (0.0059, 25) and 98.4, respectively.

Two homeotypical phases occur at the mole fraction xAl≈0.75 in the ternary system Co-Ni-Al: the pseudoternary intermetallic compound (Co, Ni)4Al13(h) (space group C2/m, Pearson code mC(34-1.8)) [Notation, according to Parthé et al. (1993). TYPIX, Standardized Data and Crystal Chemical Characterization of Inorganic Structure Types (Springer, Berlin), Vol. 2, p. 269, Vol. 3, p. 1055]. For structures with partly occupied sites, the hybrid Pearson code is given as (the sum of the multiplicities of all, fully or partly occupied sites in the unit cell)−(number of structural vacancies in the unit cell)], and the ternary compound Co2NiAl9 (Immm, oI96). Powder diffraction data are reported for these materials or phases—from the viewpoint of phase equilibria—immediately neighboring phases.