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The natural sII-type clathrasil chibaite [chemical formula SiO 2 ·( M 12 , M 16 ), where M x denotes a guest mol-ecule] was investigated using single-crystal X-ray diffraction and Raman spectroscopy in the temperature range from 273 to 83 K. The O atoms of the structure at room temperature, which globally conforms to space group [ V = 7348.9 (17) Å 3 , a = 19.4420 (15) Å], have anomalous anisotropic displacement parameters indicating a static or dynamic disorder. With decreasing temperature, the crystal structure shows a continuous symmetry-lowering transformation accompanied by twinning. The intensities of weak superstructure reflections increase as temperature decreases. A monoclinic twinned superstructure was derived at 100 K [ A 2/ n , V = 7251.0 (17) Å 3 , a ' = 23.7054 (2), b ' = 13.6861 (11), c ' = 23.7051 (2) Å, β' = 109.47°]. The transformation matrix from the cubic to the monoclinic system is a i ' = (½ 1 ½ / ½ 0 -½ / ½ -1 ½). The A 2/ n host framework has Si-O bond lengths and Si-O-Si angles that are much closer to known values for stable silicate-framework structures compared with the averaged model. As suggested from band splitting observed in the Raman spectra, the [5 12 ]-type cages (one crystallographically unique in , four different in A 2/ n ) entrap the hydro-carbon species (CH 4 , C 2 H 6 , C 3 H 8 , i -C 4 H 10 ). The [5 12 6 4 ]-type cage was found to be unique in both structure types. It contains the larger hydro-carbon mol-ecules C 2 H 6 , C 3 H 8 and i -C 4 H 10 .

A study of the ternary Rh-Mn-Bi phase diagram revealed the existence of two new ternary bismuthides, viz. hexarhodium pentamanganese octadecabismuthide (Rh 6 Mn 5 Bi 18 ) and rhodium manganese tribismuthide (RhMnBi 3 ). Their crystal structures represent new structure types. Rh 6 Mn 5 Bi 18 , with a Wyckoff sequence a f2 g2 i5, crystallizes in the tetragonal system (space group P4 2 /mnm; Pearson symbol tP58), and RhMnBi 3 , with a Wyckoff sequence a c g i q, crystallizes in the orthorhombic system (Cmmm; oS20). In the Rh 6 Mn 5 Bi 18 structure, the transition metal atoms are linked into ribbon-like structural units aligned along the [001] direction, whereas planar sheets are formed in RhMnBi 3 . In both crystal structures, the units formed by the transition metal atoms are enveloped by Bi atoms, which themselves form a loosely bound network. The linkage results in a layer structure for RhMnBi 3 , while in the case of Rh 6 Mn 5 Bi 18 , a three-dimensional network is formed; the latter, however, contains several areas where Bi...Bi distances suggest van der Waals interactions. Both phases under discussion have analogous structural motifs., (open access.)

The stannides CuLi 2 Sn (CSD-427095) and Cu 2 LiSn (CSD-427096) were synthesized by induction melting of the pure elements and annealing at 400 °C. The phases were reinvestigated by X-ray powder and single-crystal X-ray diffractometry. Within both crystal structures the ordered CuSn and Cu 2 Sn lattices form channels which host Cu and Li atoms at partly mixed occupied positions exhibiting extensive vacancies. For CuLi 2 Sn, the space group F-43m. was verified (structure type CuHg 2 Ti; a =6.295(2) Å; wR 2 ( F ²)=0.0355 for 78 unique reflections). The 4( c ) and 4( d ) positions are occupied by Cu atoms and Cu+Li atoms, respectively. For Cu 2 LiSn, the space group P 6 3 / mmc was confirmed (structure type InPt 2 Gd; a =4.3022(15) Å, c =7.618(3) Å; wR 2 ( F ²)=0.060 for 199 unique reflections). The Cu and Li atoms exhibit extensive disorder; they are distributed over the partly occupied positions 2( a ), 2( b ) and 4( e ). Both phases seem to be interesting in terms of application of Cu-Sn alloys as anode materials for Li-ion batteries.

The complete Cd-Pr equilibrium phase diagram was investigated with a combination of powder-XRD, SEM and DTA. All intermetallic compounds within this system, already reported in literature, could be confirmed: CdPr, Cd2Pr, Cd3Pr, Cd45Pr11, Cd58Pr13, Cd6Pr and Cd11Pr. The corresponding phase boundaries were determined at distinct temperatures. The homogeneity range of the high-temperature allotropic modification of Pr could be determined precisely and a limited solubility of 22.1 at.% Cd was derived. Additionally, single-crystal X-ray diffraction was employed to investigate structural details of Cd2Pr; it is isotypic to the AlB2-type structure with a z value of the Cd site of 0.5. DTA results of alloys located in the adjacent two-phase fields of Cd2Pr suggested a phase transformation between 893 and 930°C. For the phase Cd3Pr it was found that the lattice parameter a changes linearly with increasing Cd content, following Vegard's rule. The corresponding defect mechanism could be evaluated from structural data collected with single-crystal XRD. Introduction of a significant amount of vacancies on the Pr site and the reduction in symmetry of one Cd position (8c to 32f) resulted in a noticeable decrease of all R-values.

The noncentrosymmetric space group P43m but a pseudocentric cubic crystal structure were reported for the compound Ni5.20Sn8.7Zn4.16Cu1.04 [Larsson et al. (1994). Acta Cryst. C50, 9-12]. The recently described Ni2Sn2Zn shows a closely related structure, although it is centrosymmetric and contains additional voids which are partially occupied. Therefore, a new refinement of Ni5.20Sn8.7Zn4.16Cu1.04 based on the originally published structure factors was performed. The results indicate that the structure can indeed be described in the centrosymmetric space group Pm3m; no justification for the absence of the inversion centre could be found within the accuracy of the available data. In comparison with Ni2Sn2Zn, slight but significant differences were confirmed; consequently, the two structures are topologically related but not isotypic.

Dinickel ditin zinc, Ni(2)Sn(2)Zn, crystallizes in the cubic space group Pm3m, with a lattice parameter of a = 8.845 (1) Å and with all atoms occupying special positions. The crystal structure exhibits pronounced similarities with that of the quaternary compound Ni(5.20)Sn(8.7)Zn(4.16)Cu(1.04). It shares structural features with other compounds in the Ni-Sn-Zn system, such as Ni(5)Sn(4)Zn and Ni(3)Sn(2).

The ternary phase diagram Al-Ge-Ni was investigated between 0 and 50 at.% Ni by a combination of differential thermal analysis (DTA), powder- and single-crystal X-ray diffraction (XRD), metallography and electron probe microanalysis (EPMA). Ternary phase equilibria and accurate phase compositions of the equilibrium phases were determined within two partial isothermal sections at 400 and 700 °C, respectively. The two binary intermediate phases AlNi and Al 3 Ni 2 were found to form extended solid solutions with Ge in the ternary. Three new ternary phases were found to exist in the Ni-poor part of the phase diagram which were designated as τ 1 (oC24, CoGe 2 -type), τ 2 (at approximately Al 67.5 Ge 18.0 Ni 14.5 ) and τ 3 (cF12, CaF 2 -type). The ternary phases show only small homogeneity ranges. While τ 1 was investigated by single crystal X-ray diffraction, τ 2 and τ 3 were identified from their powder diffraction pattern. Ternary phase reactions and melting behaviour were studied by means of DTA. A total number of eleven invariant reactions could be derived from these data, which are one ternary eutectic reaction, six transition reactions, three ternary peritectic reactions and one maximum. Based on the measured DTA values three vertical sections at 10, 20 and 35 at.% Ni were constructed. Additionally, all experimental results were combined to a ternary reaction scheme (Scheil diagram) and a liquidus surface projection.

Work on the ternary Ni-Sn-Zn phase diagram revealed the existence of the title compound pentanickel tetratin zinc, Ni(3.17)Sn(2.67)Zn(0.67) [Schmetterer et al. (2012). Intermetallics, doi:10.1016/j.intermet.2011.05.025]. It crystallizes in the Ni(5)Ga(3)Ge(2) structure type (orthorhombic, Cmcm) and is related to the InNi(2) type (hexagonal, P6(3)/mmc) of the neighbouring Ni(3)Sn(2) high-temperature (HT) phase, but is not a superstructure. The crystal structure was determined using single-crystal X-ray diffraction. Its homogeneity range was characterized using electron microprobe analysis. Phase analysis at various temperatures indicated that the phase decomposes between 1073 and 1173 K, where a more extended ternary solid solution of the Ni(3)Sn(2) HT phase was found instead.

The Al-Fe-Si system was studied for an isothermal section at 800 °C in the Al-rich part and at 900 °C in the Fe-rich part, and for half a dozen vertical sections at 27, 35, 40, 50 and 60 at.% Fe and 5 at.% Al. Optical microscopy and powder X-ray diffraction (XRD) was used for initial sample characterization, and Electron Probe Microanalysis (EPMA) and Scanning Electron Microscopy (SEM) of the annealed samples was used to determine the exact phase compositions. Thermal reactions were studied by Differential Thermal Analysis (DTA). Our experimental results are generally in good agreement with the most recent phase diagram versions of the system Al-Fe-Si. A new ternary high-temperature phase τ 12 ( cF 96, NiTi 2 -type) with the composition Al 48 Fe 36 Si 16 was discovered and was structurally characterized by means of single-crystal and powder XRD. The variation of the lattice parameters of the triclinic phase τ 1 with the composition Al 2+ x Fe 3 Si 3- x (-0.3 <  x  < 1.3) was studied in detail. For the binary phase FeSi 2 only small solubility of Al was found in the low-temperature modification LT-FeSi 2 ( ζ β ) but significant solubility in the high-temperature modification HT-FeSi 2 ( ζ α ) (8.5 at.% Al). It was found that the high-temperature modification of FeSi 2 is stabilized down to much lower temperature in the ternary, confirming earlier literature suggestions on this issue. DTA results in four selected vertical sections were compared with calculated sections based on a recent CALPHAD assessment. The deviations of liquidus values are significant suggesting the need for improvement of the thermodynamic models.