Rietveld refinement of the crystal and magnetic structures of LixMnO2 (x 1⁄4 0.98, 1.00, 1.02) are performed using neutron and X-ray measurements. A significant structural disorder due to the presence of manganese ions in lithium positions (MnLi) and lithium ions in manganese ones (LiMn) is found to be a common feature of Li0.98MnO2, Li1.00MnO2, and Li1.02MnO2. An essential anisotropy of the th...

A search for superconductivity in systems of CuCl/Si and CuCl2/Si leads to the observation of ferromagnetism with a Tc of 18 K in powder samples. The magnetism emerges when pure CuCl is exposed to humid air, while the observed magnetic moment depends on the exposure level. We used magnetic field modulated microwave spectroscopy, as well as SQUID magnetometry, to identify magnetic phase transiti...

The crystalline structures of the superionic high-temperature copper selenides Cu(2-x)Se (0 < x < 0.25) produced using mechanical alloying were investigated using X-ray diffraction (XRD). The measured XRD patterns showed the presence of peaks corresponding to the crystalline superionic high-temperature alpha-Cu(2)Se phase in the as-milled sample, and its structural data were determined by means...

X-ray powder diffraction and chemical analyses show that mammalian dental enamel apatite is an impure form of hydroxylapatite, Ca10(PO4)6(OH)2 (structure described in Elliott 1994). The major difference of enamel apatite from hydroxylapatite is in the presence of about 3 wt% CO3. Details of the crystallographic structures of carbonate-containing apatites (including minerals) are important becau...

Abstraet.The crystal structure of the new zeolite mineral gobbinsite, Cao.6Na2.6K2.2Al6Si¡o032 . 12H20, has been determined in the space groupPmn2¡ with a = 10.108(1), b = 9.766(1) and e = 10.171(1) Á. The topology of the framework is the same as that of gismondine and can be describedas a stacking of2-dimensional arrays of double crankshaft chains. The structure was refined by the Rietveld tec...

The line-broadening of a sample of a powder of non-stoichiometric hexagonal ε-iron nitride with the average composition FeN0.433 was analysed by X-ray diffraction. A nearly Gaussian purely strain-like broadening was observed. The broadening is strongly orientation dependent. For each direction of the diffraction vector relative to the crystallographic axes the width of the reflections varies pr...

The crystal structures of triethyl-1,3,5-triazine-2,4,6-tricarboxylate (I), triethyl-1,3,5-benzenetricarboxylate (II) and tris-2-hydroxyethyl isocyanurate (III) have been determined from conventional laboratory X-ray powder diffraction data using the differential evolution structure solution technique. The determination of these structures presented an unexpectedly wide variation in levels of d...

The structural characterization of the new iron-zinc hepta-borate bromide with composition Fe(1.59)Zn(1.41)B(7)O(13)Br, prepared by chemical transport is reported. A rigid-body model with constrained generalized coordinates was defined in order to hold the positions of the B atoms at reasonable inter-atomic distances that typically would reach unacceptable values because of the weak scattering ...