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The peeling of an onion: Embedded in the voids of an infinite cationic [Te32Ni30X3O90]5+ network lies an icosahedral [Ni4X13]5- anionic guest cluster (ochre). It may be considered wrapped and trapped in a successive series of concentric skins made from the lone pairs of Te atoms (blue), the Te (yellow), O (red), and Ni atoms (light blue polyhedra). But are there any other guests?
Two series of [(Ln1/3Sr2/3S)1.5]1.15NbS2and (Ln1-xSrxS)1+yNbS2misfit layer sulfides have been synthesized and studied by X-ray powder and single crystal diffraction, electron diffraction, and EDX-analysis. The [(Sm1/3Sr2/3S)1.5]1. 15NbS2compound belongs to the 1.5Q/1H homologue type where the Sr-cations are mainly located at the exterior of the Q-slab whereas Sm preferably occupy the positions at
The systems AeAl2-xMgx (Ae = Ca, Sr, Ba) display electron concentration induced Laves phase structural changes. However, the complete sequence MgCu2 → MgNi2 → MgZn 2 with increasing x (decreasing electron count) is only observed for Ae = Ca. Compounds SrAl2-xMgx (0 < x ≤ 2) and BaAl2-xMgx (x = 0.85 and 2.0) were synthesized and structurally characterized by X-ray diffraction experiments. For the S
The quasicrystal approximant Eu4Cd25, formerly designated EuCd6, was synthesized and characterized by means of single-crystal X-ray diffraction. Superstructure reflections corresponding to an F-centered cubic unit cell with a doubled cell-parameter relative to the I-centered cubic sub-cell could be observed in the diffraction data. This gives the largest cubic unit cell reported to date among bina
The incommensurately modulated structure of ζ-Zn3-xSb 2 was solved and refined versus X-ray single crystal diffraction data using a 3+1 dimensional superspace formalism. The compound crystallizes in the orthorhombic system in the 3+1 dimensional superspace group Pnna(α0)0s0 with the cell parameters a=7.283(3)Å, b=15.398(5)Å, c=25.06(1)Å, q=(α,0,0), α≈0.385. The structure features columns of interg
The title compounds were synthesized from MoCl2 and the appropriate commercial chlorides and their structures were solved by a combination of single crystal X-ray diffraction analysis and theoretical methods. The NH4, K and Rb compounds are essentially isostructural, and crystallize in space group Ia (No. 9) with the cell parameters (in Å) a=9.173(1), b=14.986(2), c=17.505(3), β=92.94(2)°(NH4); a=
Single crystals of Nd0.6Gd0.4Se1.85 have been prepared by chemical transport reactions starting from pre-annealed powder samples. Satellite reflections observed in X-ray and electron diffraction experiments indicate the presence of a two-dimensional lattice distortion. The origin of this is a site occupancy wave and, coupled to this, a charge density wave in the planar selenium layer of this compo
β-Zn4Sb3 is an outstanding thermoelectric material mainly due to its extraordinarily low thermal conductivity, which is similar to that of glasses. Recently it was proposed that interstitial Zn atoms are responsible for this peculiar behavior. Here we report on the crystal and electronic stucture of the low-temperature polymorph α-Zn4Sb3. During the reversible phase transition the intricate disord
The novel structure of the δ1 phase in the cobalt-zinc system was determined by single-crystal X-ray diffraction. The structure features fused double icosahedra linked by edge-and face-sharing. The δ1-CoZn7.8 structure is incommensurately modulated along the columnar b direction. The extent of the linear pentagonal antiprismatic intergrowth is limited to a maximum of two overlapping icosahedra bec
Single crystals of LaSeTe2 have been prepared by reaction of the elements in a LiCl/RbCl flux at 970 K for seven days. Satellite reflections observed in diffraction experiments indicate the presence of an incommensurate lattice distortion, which is of the charge-density-wave (CDW) type. The modulated structure has been solved from X-ray data at 173, 293, and 373 K. LaSeTe2 crystallizes in the 3+1-
The copper vanadium oxide bronze Cu2.33-xV4O 11 exhibits a three part composite structure refined on the basis of XRD low-temperature studies. It crystallizes in the triclinic system with the non-centric superspace group X1 and cell parameters a=15.280(3)Å; b 1=3.616(1)Å; c=14.674(3)Å; α=90.0°; β=101.95(3)°; γ=90.0° with a modulation q-vector equal to (0,0.11,0). The three different parts of this
Several of the MCd6 approximants (M=Pr, Nd, Sm, Eu, Gd, Dy, Yb, Y, and Ca) to the MCd5.7 quasicrystals (M=Yb and Ca) have been synthesized and their structures have been refined from single-crystal x-ray-diffraction data; the different types of disorder of the central Cd4 tetrahedra located in the dodecahedral cavities of these closely related compounds have been examined and mutually compared. A
New niobium-based misfit sulfides (Ln1/3Sr2/3S)1.5]1.15 NbS2 (Ln = Sm, Tb) have been synthesized from a mixture of SrS, Ln2S3, Nb(m), and S in evacuated and sealed silica tubes by annealing at 1000 °C for 144 h under a sulfur partial pressure of 49.3 kPa. The compounds have been characterized by EDX analysis, X-ray single crystal and powder diffraction, electron diffraction, and magnetic susceptib
Synthesis, X-rays, TEM and HREM studies of the composition x = 0.25 of the solid solution Sb2W1-xMoxO6 are reported. The phase crystallises in the monoclinic system, space group C2 and the cell parameters of its average structure are a = 11.1296(6) Å, b = 9.8868(9) Å, a = 18.501(2) Å, and β = 96.951(9)°. Mo and W atoms are ordered in the 1/3 ratio. Twining and extended defects have been studied by
A single crystal of the cubic spinel LiMn2O4 was delithiated electrochemically at 4.06 V vs. Li/Li+ to probe the structural source of the inflection point at ca. 4.1 V vs. Li/Li+ in the discharge curve. The phase thus obtained was investigated by single-crystal X-ray diffraction and the structure refined. The structure is closely related to the original cubic structure, but the new space group is
Solid-state synthesis in the Bi-Se system produced both commensurate and incommensurate phases of compositions ranging from Bi2Se3 to Bi4Se3, all crystallising in rhombohedral or trigonal layer structures. The a parameters are very similar for all phases but the c parameters vary irregularly between 10 and 100 Å. A general model for all these phases was developed, using single crystal X-ray diffra
Nanoporous carbons have been prepared through a selective etching reaction, performed by halogenisation of aluminum carbide. The structures obtained can be controlled by varying the chlorination temperature. The unique set of nanocarbons obtained include nanoporous amorphous structures, the nanobarrel structure and a nanographitic structure as chlorination temperatures were increased from 400 °C t
The first known example of a regular face-sharing icosahedra helix is presented in the novel crystal structure of δCo2Zn15, solved and refined from single-crystal X-ray and neutron powder diffraction data. The compound δCo2Zn15 is also the first example of an intermetallic compound crystallizing in the acentric hexagonal space group P62. The parameters from the single crystal refinement are a = 11
The title compound Dy13Zn57, crystallizes in the orthorhombic space group Pnma (No. 62) with the cell parameters a = 14.060(5), b = 14.260(5) and c = 24.700(3) Å. The structure has formerly been described as Dy13Zn58 with the hexagonal type structure of Gd13Zn58. Single-crystal X-ray diffraction measurements however, show extra reflections breaking the C-centering of the corresponding orthorhombic
The title compound was synthesized according to Andersson Acta Chem. Scand. 18 (1964) 2233. The structure is an incommensurately modulated variation of the UO3 structure, in a (3 + 1)-dimensional super space description isostructural to the composite phases (1 - x)Ta2O5•xWO3 Acta Crystallogr., Sect. B 52 (1996) 223 and Acta Crystallogr., Sect. B 51 (1995) 709. The compound crystallizes in the orth
