PANI , Marcella

We report on the synthesis and crystal structure of the new family of rare earth ternary equiatomic RZnSn compounds. The phases are found to form for R = La to Nd, Sm, Gd to Lu, Y, all belonging to the hexagonal hP12-P63/mmc YPtAs structure type. The lattice parameters, as obtained by the Guinier method on polycrystalline samples, vary...

The phase diagram of the Sr–Si system has been investigated across almost the whole composition range (0–75 at.% Si) using differential thermal analysis (DTA), metallographic analysis, X-ray diffraction and electron microscopy. Four intermediate phases exist: Sr2Si (PbCl2-type), Sr5Si3 (Cr5B3-type), SrSi (CrB-type) and the dimorphic SrSi2...

The phase diagram of the Ba-Si system has been completely revised from a thermal point of view. All the already-known intermediate phases have been confirmed: Ba2Si (Co2Si type), Ba5Si3 (Ba5Si3 type), BaSi (CrB type), Ba3Si4 (Ba3Si4 type) and BaSi2 (BaSi2 type). Save for Ba5Si3, which forms peritectically, all other compounds melt congruently....

The synthesis and the crystal structure of two new intermetallic phases with formula Ca5Rh and Ca5Ir are reported. The two compounds are isotypic and crystallize with anewstructuretype. The crystal structure, elucidated by single-crystal X-ray techniques for the iridium compound and confirmed for Ca5Rh by powder data, is orthorhombic,...

The atomic volume of an AxByCz ternary intermetallic compound can be calculated starting from volumes of some proper AB, AC and BC binary phases. The three methods by Colinet, Muggianu and Kohler, originally used to estimate thermodynamic quantities, and a new method here proposed, were tested to derive volume data in eight systems containing...

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The phase diagram of the Yb-Ge system was investigated over the whole compositional range by means of differential thermal analysis (DTA), X-ray diffraction (XRD), optical microscopy (LOM) and electron probe microanalysis (EMPA). Besides the already known intermediate phases Yb2Ge (PbCl2-type), Yb5Ge3 (Mn5Si 3-type), Yb11Ge10 (Ho11Ge 10-type)...

The phasediagram of the Ba–Gesystem has been revised, in the composition range 0–75 at.% Ge, from a thermal point of view, resulting substantially different from that previously reported in Massalski collection. The existence and composition of the following compounds are confirmed: Ba2Ge, Ba5Ge3, BaGe, dimorphic Ba3Ge4, BaGe2, Ba6Ge25 and...

Segments of the basic structures BaAl4, AlB2, W, Po, Cu3Au, CaF2 or hybrids obtained combining two segments of these types are used with the mechanism of intergrowth to describe nine linear structures of binary and ternary intermetallic compounds formed by rare earth or alkaline earth metals. Such a representation allows to display relationship...

The crystal structure of Ba5Ga6 was determined by single-crystal diffractometry. It is hexagonal, hP22, space group P6c2 (n. 188), a = 7.771(2) A ̊, c = 14.376(4) A ̊, Z = 2, refined with anisotropic displacement factors, R = 0.076 with 358 reflections, and contains a disordered Ba position with partial occupation. The structure is...

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In the crystal structure of C12H11ClO, the (planar) molecules give rise to a parallel packing. A model crystal obtained by semi-empirical and packing-energy calculations is consistent with the observed structure.

The intermetallic compounds Yb2Ge, Eu2Ge and Eu2Si were synthesized from the elements by HF melting in tantalum crucibles. The three phases crystallize in the PbCl2 structure type, as shown by Rietveld refinement of powder pattern intensity data. The structure of Yb2Ge was confirmed by a single crystal study.

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The synthesis and crystal structure of the new family of rare earth ternary equiatomic RZnGe phases are reported. The compounds are found to form for R = La to Nd, Sm, Gd to Tm, Y, all crystallizing with the hexagonal hP12-P63/mmc YPtAs structure type, a four-layers superstructure derivative of the AlB2 type. No formation of the equiatomic...

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The structures of ScAuSi, YAuSi and LuAuSi were determined by single-crystal diffractometry. ScAuSi, hP6, hexagonal P6m2 (no. 187), a=4.212(1) A ̊, c=7.546(3) A ̊, Z=2, R=0.039 using 66 reflections, represents a new ternary ordered type. YAuSi, hP6, hexagonal P63mc (no. 186),a=4.288(2) A ̊, c=7.546(3) A ̊, Z=2, R=0.039 using 66 reflections, is...

The ternary intermetallic compounds R3NiSi3 (R = La, Ce, Pr, Nd, Sm, Gd, Tb, Dy, Er, Tm), R3FeSi3 (R = Er, Tm) and R3CoSi3 (R = Er) have been synthesized and structurally characterized by X-ray diffraction on powders and single crystals. In particular, within the nickel series, the lighter rare earths (from La to Dy) adopt the orthorhombic...

The synthesis and structural characterization of phases in the R–Li–Ge (R = rare earth) systems are reported. The R4LiGe4 compounds with R = La–Nd, Sm complete the series, where the analogues with R = Gd–Tm, Lu were confirmed, all crystallizing with the Tm4LiGe4 type. Nd4LiGe4 and Ho4LiGe4 were structurally studied by single crystal X-ray...

The new R2Co2Al compounds (R = Pr, Nd, Sm, Gd, Tb, Dy, Ho, Er, Tm, Y), studied by single crystal and powder X-ray diffraction, crystallize with the W2CoB2 structure type. Pr2Co2Al is dimorphic, showing also its own monoclinic structure (a = 9.595 Å, b = 5.602 Å, c = 7.753 Å, β = 103.89°), which is closely related to the W2CoB2 type. Both...

Seventeen new RMX phases were synthesized in the systems with R Ca, Sr, Ba, Eu, Yb, M Mg, Hg and X Si, Ge, Sn, Pb. X-Ray analysis on powders and single crystals assigned the phases to five structure types: ZrBeSi, LiGaGe, TiNiSi, CeCu2 and ZrNiAl. The distribution of 180 possible RMX compounds among eight structural types is discussed in a...

25 new RMX phases (R ≡ Ca, Sr, Ba, Eu, Yb; M ≡ Zn, Cd; X ≡ Si, Ge, Sn, Pb) were found to crystallize in the structure types ZrBeSi, LiGaGe, TiNiSi, ZrNiAl and CeCu2. Single-crystal refinements were made for YbZnSn (LiGaGe type) with complete atomic ordering, and for SrCdSn, BaCdSn and BaCdPb with disordered CeCu2 structure. A two-dimensional...

19 intermetallic compounds with the general formula RMX (R ≡ Ca, Sr, Ba, Eu, Yb; M ≡ Cu, Ag, Au; X ≡ Sb, Bi) were synthesized and structurally studied by X-ray methods on powders and single crystals. The ternary phases crystallize in four ordered structural types: ZrBeSi, LiGaGe, TiNiSi and MgAgAs. Some comments are given on the parameters...

The ternary RAgX phases, with R = Ca, Sr, Ba, Eu, Yb and X = Si, Ge, Sn, Pb, were structurally studied by means of X-ray diffraction on powders and single crystals. The tin and lead compounds exist on the equiatomic composition and crystallize in the CeCu2, CaLiSn and YbAgPb types. The silicon and germanium compounds are in most cases...