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1.
The Pentatellurides M2Te5 (M = Al, Ga, In): Polymorphism, Structural Relations, and Homogeneity Ranges The hitherto unknown crystal structure of the black solid Al2Te5 is solved by Rietveld refinement of X-Ray powder data: a = 1359.29(3) pm, b = 415.27(1) pm, c = 983.92(2) pm, β = 126.97(1)°, space group: C2/m (no. 12), Z = 2. In contrast to Ga2Te5 and In2Te5Al2Te5 is very sensitive to hydrolysis. It can formally be described as Te[AlTe3/3Te1/1]2, containing layers made up of chains of cis-edge-sharing AlTe4 tetrahedra [AlTe3/3Te1/1] and additional Te atoms. In2Te5-I and In2Te5-II are characterized by layers with a similar topology, Ga2Te5 however is different. It has no layer structure, but contains chains of trans-edge-sharing GaTe4-tetrahedra and additional Te-atoms according to the formulation Te[GaTe4/2]2. It can be regarded as a variant of the TlSe type structure. From heterogeneous samples with the nominal composition In0.5Ga1.5Te5 single crystals of a new stacking variant (In2Te5-III) of the In2Te5 structure type can be isolated. The composition of the crystals, determined by single crystal structure analysis, is In0.77Ga1.23Te5, with a = 1613.2(3) pm, b = 424.6(1) pm, c = 1330.5(2) pm, β = 97.39(1)°, space group C2/c (Nr. 15), Z = 4. This structure type is not yet known for unsubstituted In2Te5. The range of homogeneity for Ga2Te5 with respect to the substitution of Gallium by Indium is given by Ga2-xInxTe5 (x < 0.4). Within the limits of experimental error however a substitution of Te in Ga2Te5 by Se cannot be detected. 相似文献
2.
Tetrapnictidotitanates(IV) M4TiX4 (M = Sr, Ba; X = P, As), hierarchical Derivatives of the KGe Structure K4□Ge4 The four new tetrapnictidotitanates(IV) Sr4TiP4, Sr4TiAs4, Ba4TiP4 and Ba4TiAs4 are synthesized from the binary pnictides MX (M = Sr, Ba and X = P, As) and elementary titanium in tantalum ampoules. The compounds are isotypic and isoelectronic with Ba4SiAs4 (space group P4 3n (no. 218); cP72; Z = 8; Sr4TiP4: a = 1259.0(1) pm; Sr4TiAs4: a = 1288.3(4) pm; Ba4TiP4: a = 1316.6(2) pm; Ba4TiAs4: a = 1346.9(2) pm). The transition metal compounds form cubic, metallic reflecting crystals (Sr4TiP4 (green); Sr4TiAs4 (silver coloured); Ba4TiP4 (silver coloured); Ba4TiAs4 (violet). They are semiconducting and very sensitive against air and moisture. The structure is a hierarchical derivative of Cr3Si (A15) and KGe type: Cr6Si2 ? (□Ge4K4)6(□Ge4K4)2 ? (TiX4M4)6(TiX4M4)2, where Ti occupies the positions of the Cr3Si structure, and the alkaline-earth metal and pnicogen atoms occupy the positions of the KGe structure. Therefore, Ti is surrounded by four X and four more distant M atoms forming a heterocubane. The mean bond lengths are: d (Ti? P) = 238.0(5) pm; 307 ? d(Sr? P) ? 333 pm; d (Ti? As) = 245.9(4); 313 ? d(Sr? As) ? 341 pm; d (Ti? P) = 240.5(5); 324 ? d(Ba? P) ? 348 pm; d (Ti? As) = 248.3(3) pm; 331 ? d(Ba? As) ? 355 pm. 相似文献
3.
Structural and Magnetochemical Studies of Ba5Mn3F19 and Related Compounds AII5MIII3F19 Single crystal structure determinations by X‐ray methods were performed at the following compounds, crystallizing tetragonally body‐centred (Z = 4): Sr5V3F19 (a = 1423.4(2), c = 728.9(1) pm), Sr5Cr3F19 (a = 1423.5(2), c = 728.1(1) pm), Ba5Mn3F19 (a = 1468.9(1), c = 770.3(1) pm, Ba5Fe3F19 (a = 1483.5(1), c = 766.7(1) pm), and Ba5Ga3F19 (a = 1466.0(2), c = 760.1(2) pm). Only Ba5Mn3F19 was refined in space group I4cm (mean distances for elongated octahedra Mn1–F: 185/207 pm equatorial/axial; for compressed octahedra Mn2–F: 199/182 pm), the remaining compounds in space group I4/m. In all cases the octahedral ligand spheres of the M1 atoms showed disorder, the [M1F6] octahedra being connected into chains in one part of the compounds and into dimers in the other. The magnetic properties of the V, Cr and Mn compounds named above and of Pb5Mn3F19 and Sr5Fe3F19 as well were studied; the results are discussed in context with the in part problematic structures. 相似文献
4.
Single crystals ((Ba0.78(1)Sr0.22)4O)Bi2 and ((Ba0.62(1)Sr0.38)10N2O)Bi4 were successfully prepared from melt beads of Ba, Sr, and Bi in nitrogen atmosphere with oxygen impurities. The phases can be prepared in single phase from the appropriate mixtures of alkaline‐earth metal, bismuth, and bismuth oxide upon heating in pure nitrogen atmosphere. ((Ba0.78(1)Sr0.22)4O)Bi2 crystallizes in the K2NiF4 structure type (space group I4/mmm, No. 139, a = 522.34(5) pm, c = 1844.0(2) pm, Z = 2, Rgt(F) = 0.039) with layers of vertex‐sharing octahedra ((Ba,Sr)4/2Ba2O). ((Ba0.62(1)Sr0.38)10N2O)Bi4 crystallizes as an isotype of Sr4Ti3O10 (space group I4/mmm, No. 139, a = 531.3(1) pm, c = 3983.2(4) pm, Z = 2, Rgt(F) = 0.050) containing slabs of three layers of vertex‐sharing octahedra further connected via corners. These compounds are interpreted in terms of members of an inverse Ruddlesden‐Popper series with the general formula n (A3ONn?1)Bi · ABi or (A3n+1ONn?1)Bin+1, respectively, with n = 1, 3. Partial order of the alkaline‐earth metal ions is analyzed. 相似文献
5.
Ternary rare earth platinum aluminides were prepared by arc‐melting of the elemental components followed by annealing in a high‐frequency furnace. Their crystal structure was determined for the yttrium compound from four‐circle X‐ray diffractometer data. It has hexagonal symmetry with a = 428.1(1) pm, c = 1638.3(3) pm, space group P63/mmc, and was refined to a conventional residual of R = 0.018 for 325 F values and 19 variable parameters. Of the five crystallographic positions, the yttrium position and one of the three aluminum positions show partial occupancies corresponding to the composition Y1.357(3)Pt4Al9.99(2) with the Pearson symbol hP20 — 4.65. These partially occupied sites are that close to each other that at best only one can be fully occupied. A model for an ordered distribution of occupied and unoccupied Y and Al sites requires a √3 larger a axis with the Pearson symbol hP20 — 4.67 for the subcell, very close to the experimental result. Corresponding superstructure reflections could be observed on an image‐plate single‐crystal diffractometer only in the form of diffuse streaks. The compound has the ideal composition Y2Pt6Al15 with Z = 2 for the superstructure. This corresponds to the formula Y1.33Pt4Al10 with Z = 1 for the subcell. The compounds A1.33Pt4Al10 with A = Gd, Tb, Dy, Ho, Er, Tm were found to be isotypic with that of the yttrium compound. This structure is closely related to or isotypic with, respectively, those of Yb2Fe4Si9, Sc1.2Fe4Si9.8, Ce1.2Pt4Ga9.8, Ce2Pt6Ga15, Tb0.67Ni2Ga5—xSix, RE0.67Ni2Ga5—xGex> (with RE = Y, Sm, Ho), and Gd0.67Pt2Al5, reported in earlier investigations. The new compound Zr1.00(1)Pt4Al10.22(3) has nearly the same hexagonal structure with a = 426.1(1) pm and c = 1622.8(3) pm. It was refined from four‐circle diffractometer data to a residual of R = 0.021 for 288 structure factors and 19 variable parameters. 相似文献
6.
《Journal of solid state chemistry》1986,62(2):133-137
Four ternary phases MPtSi (M = Ca, Eu, Sr, Ba) have been shown to crystallize in the LaIrSi-type structure (space group P213). This ternary structure is a derivative structure of the binary SrSi2-type structure (space group P4332 or P4132). In the MPtSi series the LaIrSi-type structure has a stability range for metals with radii from rCa = 1.973 Å to rBa = 2.243 Å in contrast to MSi2 compounds which exist with the SrSi2-type structure only from rSr = 2.151Å to rBa 2.243 Å. From a single-crystal investigation on CaPtSi remarkably short PtSi distances of 2.30 Å (3x) are obtained. Structural relations are discussed. 相似文献
7.
Caroline Rhr 《无机化学与普通化学杂志》1995,621(9):1496-1500
Novel Suboxide Clusters [O5Ba18] in the Crystal Structures of Ba21M2O5 (M = Si, Ge) The compounds Ba21M2O5 (M = Si, Ge) crystallize in the cubic system with space group Fd3m, lattice constants 2 038.3(10) pm (Si), 2 039.8(9) pm (Ge) resp. and Z = 8. The crystal structure contains isolated Si/Ge atoms coordinated by barium atoms in an icosahedral arrangement. The oxygen atoms are situated in the centers of barium octahedra, four of which share common faces with an additional central octahedron. The novel clusters [O5Ba18] in principal are related to those in the crystal structures of the binary Cs/Rb suboxides. 相似文献
8.
Brigitte Eisenmann Michael Rhode Marco Wendorff Caroline Röhr Prof. Dr.‐Ing. 《无机化学与普通化学杂志》2008,634(1):153-165
New Sr Compounds with Planar Al‐Si/Ge Anions and a Correction of SrSi‐II and SrGe0.76 Planar anions with considerable pπ‐pπ interactions between heavier group 13 and 14 elements are observed in several alkaline earth trielides and tetrelides. In the intermetallics of the series SrAlxGe2?x (border phases: x = 1: , a = 429.4(3), c = 474.4(3) pm, Z = 1, R1 = 0.0305, SrPtSb type and x = 1.6: P6/mmm, a = 440.4(2), c = 478.2(2) pm, Z = 1, R1 = 0.0125, AlB2 type) graphite analogue planar Al/Ge nets with short Al‐Ge bonds are stacked in identical orientation, showing inter‐layer distances of approx. 475 pm. Starting from the related planar ribbons of condensed six‐membered rings in the known intermetallics (MIV = Si, Ge) a series of new metal‐rich oxides with chain pieces consisting of three, two and finally only one six‐membered ring have been prepared and characterized on the basis of single crystal X‐ray data. The formal fragmentation of the ribbons is achieved by the incorporation of [OSr6] octahedra, chains of which (connected via common corners) exactly fit the distance between the planar anions. The structures of the two compounds (MIV = Si, Ge; formerly erroneously reported as SrSi and SrGe0.76, space group Immm, a = 482.48(5)/484.55(8), b = 1306.5(2)/1342.2(2), c = 1814.0(2)/1857.4(3) pm, Z = 2, R1 = 0.0369/0.0316) contain isolated planar anions [M2Al2M2Al2M2]18? with only one six‐membered ring. In the monoclinic structures of the silicide Sr13[Al6Si8][O] (C2/m, a = 2245.1(4), b = 482.76(5), c = 1720.6(5) pm, β=125.21(2)°, Z = 2, R1 = 0.0579) and the germanide Sr16[Al8Ge10][O] (C2/m, a = 2287.23(14), b = 484.94(3), c = 2065.70(13) pm, β=120.150(4)°, Z = 2, R1 = 0.0730) anions [Si2Al2Si2Al2Si2Al2Si2] and [Ge2M2Ge2M2Ge2M2Ge2M2Ge2] with two and three six‐membered rings are left as fragments of the ribbons in Sr3Al2M2. The puzzling bonding situation in these type of polar intermetallics at the Zintl border is calculated (using the DFT FP‐LAPW approach) for the structures with manageably small unit cells and discussed for the series SrAlM – Sr3Al2M2 – Sr16[Al8M10][O] – Sr13[Al6M8][O] – Sr10[Al4M6][O]. 相似文献
9.
Hashimoto T. Yoshinaga M. Ueda Y. Komazaki K. Asaoka K. Wang S. 《Journal of Thermal Analysis and Calorimetry》2002,69(3):909-917
The phase transitions of Ba2-xSrxIn2O5 were investigated with various thermal analyses and high-temperature X-ray diffraction. It was clarified that crystal structure
of Ba2-xSrxIn2O5 with x=0.0~0.4 varies from brownmillerite through distorted perovskite to another distorted perovskite with increase of temperature.
The phase transition from brownmillerite to distorted perovskite was revealed to be first order, whereas transition from distorted
perovskite to another one was second order. The specimen with x≥0.5 showed only one first order phase transition from brownmillerite to distorted perovskite. The phase diagram of Ba2-xSrxIn2O5 was established and existence of tricritical point at ~1100°C with x=0.4~0.5 was suggested.
This revised version was published online in August 2006 with corrections to the Cover Date. 相似文献
10.
On the A2?2xSn5+xCl12 (A = K, In) Phases The refinement of the structure of A2-2xSn5+xCl12 compounds (A = K+, In+) with single crystal data is reported. They crystallize with the Th7S12 type arrangement (a = 1192(2) pm, c = 428.9(8) pm (K-compound); a = 1189.8(6) pm, c = 431.2(3) pm (In-compound)) for which we propose the space group P6 . The possibility of meroedric twinning is discussed. Due to the composition of these compounds the structure is necessarily disordered and this leads to a wide range of homogeneity which can be influenced by the size and the polarity of the A type cation. 相似文献
11.
The systems CaHPO4−MHPO4−H2O (M=Sr, Ba) were studied at 50°C. ForM=Sr, the series of single phases, Ca1−xSrxHPO4 for 0.95<X<0.75 and CaxSr1−xHPO4 for 0.4<X<1 have been prepared.
These solid solution were caracterized by their infrared spectra and their crystallographic unit cell parameters.
ForM=Ba a new phase Ca2Ba(HPO4)3 has been determined. It was characterized by DRX, IR, ATD and chemical analyses.
Zusammenfassung Bei 50°C wurde das System CaHPO4−MHPO4−H2O (mitM=Sr, Ba) untersucht. FürM=Sr wurden Serien von Einzelphasen erhalten: Ca1−xSrxHPO4 für 0.95<X< 0.75 und CaxSr1−xHPO4 für 0.4<X<1. Diese Mischkristalle wurden anhand ihrer Infrarotspektren und ihrer kristallographischen Elementarzellenparameter charakterisiert. FürM=Ba wurde die neue Phase Ca2Ba(HPO4)3 ermittelt. Sie wurde mittels DRX, IR, ATD und chemischer Analyse charakterisiert.相似文献
12.
Yu. V. Danilov A. D. Neuimin L. A. Dunyushkina L. A. Kuzmina N. S. Zybko Z. S. Martemyanova A. A. Pankratov 《Russian Journal of Electrochemistry》2007,43(1):56-63
Phase composition, electroconductivity, oxygen ion transport number, and microhardness of samples of Ln1 − x
SrxGa0.5 − y/2Al0.5 − y/2MgyO3 − δ (Ln = La, Pr, Nd; x, y = 0.10, 0.15) synthesized by a ceramic methods are studied. Methods of x-ray diffraction analysis and scanning electron microscopy
reveal the La-containing samples to be homogeneous and have a perovskite structure. Magnesium does not dissolve in Pr-and
Nd-containing systems but forms an individual phase based on magnesium oxide. Apart from magnesium oxide, in these systems
there form extrinsic phases, specifically, LnSrGa3O7 and an unknown phase. The electroconductivity of La1 − x
SrxGa1 − y
MgyO3 − δ decreases after substituting Al for Ga. Ceramic La1 − x
SrxGa0.5 − y/2Al0.5 − y/2MgyO3−δ is a purely ionic conductor in the temperature interval 500 to 1000°C; NdxSrxGa0.5 − y/2Al0.5 − y/2MgyO3 − δ has predominantly ionic conduction; and the predominant type of conduction in Pr1 − x
SrxGa0.5 − y/2Al0.5 − y/2MgyO3 − δ is electronic below 700–800°C, with the contribution of ionic conduction increasing at higher temperatures. Substituting
Al for Ga raises the hardness of ceramics under study. Among the compositions studied, La0.85Sr0.15Ga0.45Al0.45Mg0.10O3 − δ and La0.85Sr0.15Ga0.425Al0.425Mg0.15O3 − δ exhibit a combination of electroconductivity and hardness that is optimal for application as electrolyte at reduced temperatures
(600–800°C). The Pr1 − x
SrxGa0.5 − y/2Al0.5 − y/2MgyO3 − δ system possesses mixed ionic-electronic conduction and high hardness, which makes it appealing for application as oxygen-penetrable
membranes.
Original Russian Text ? Yu.V. Danilov, A.D. Neuimin, L.A. Dunyushkina, L.A. Kuz’mina, N.S. Zybko, Z.S. Martem’yanova, A.A.
Pankratov, 2007, published in Elektrokhimiya, 2007, Vol. 43, No. 1, pp. 57–65. 相似文献
13.
Layer-Anions in the Crystal Structures of the Isotypic Compounds Sr2[Ga2S5], Ba2[In2S3], and Ba2[In2Se5] The compounds Sr2[Ga2S5], Ba2[In2S5], and Ba2[In2Se5] have been prepared from stoichiometric mixtures of the elements at temperatures between 1150°C and 1250°C. They are isotypic (space group Pbca, Z = 8) with the lattice constants see ?Inhaltsübersicht”?. In the anionic part of the structure GaS4-(InS4-/InSe4)-tetrahedra share three common vertices to form layers with rings built by four and eight tetrahedra. The cations are placed between the sheets and have the coordination number seven. 相似文献
14.
New Ternary Clathrate Compounds in the Systems Barium–Indium/Zinc/Cadmium–Germanium: Zintl Compounds with Phase Width? By systematic investigations in the systems barium–indium/zinc/cadmium–germanium we found a couple of new electrovalent ternary compounds with A8X46 clathrate (I) type structures. They crystallize cubically in space-group Pm3n. For Ba8In16Ge30 (a = 1 075.8 pm), Ba8Zn8Ge38 (a = 1 082.0 pm) and Ba8Cd8Ge38 (a = 1 096.0 pm) the structures were verified by X-ray single crystal diffraction data. According to valence and bounding distances the new clathrates should be Zintl compounds. Measurements of the temperature dependence of the electrical resistivity proved, that they are indeed semiconductors. A part of the 2B/3B metal atoms can be substituted by germanium. Charge balance will be retained by creation of vacancies in the A8X46 type structures. By phase analysis the limits of the composition range were determined as Ba8In4Ge9[]3Ge30 (a = 1 084.9 pm), Ba8Zn4Ge10[]2Ge30 (a = 1 073.6 pm) and Ba8Cd4Ge10[]2Ge30 (a = 1 082.0 pm). 相似文献
15.
A Contribution on the Compound CaBeNd2O5 and Phases of the Composition M1?xMx'BeLn2O5 (M = Ca, Ba; M′ = Sr; x = 0.5). CaBeNd2O5 and the phases (I): Ba0,5Sr0,5BeLa2O5 and (II): Ca0,5Sr0,5BeDy2O5 have been prepared by high temperature reactions using a CO2-LASER. They crystallize with orthorhombic symmetry, space group D-Pnma, CaBeNd2O5: a = 9.448(1), b = 7.155(1), c = 6.483(1) Å; (I) a = 9.821(4), b = 7.436(3), c = 6.734(3) Å; (II): a = 9.352(2), b = 7.016(2), c = 6.375(2) Å; Z = 4, and belong to the isotypic series CaBeLn2O5 and SrBeLn2O5. Calculations of Coulomb energies of ordered BaBeLn2O5 and EuBeLn2O5 and disordered CaBeLn2O5, SrBeLn2O5 and EuBeNd2O5 show dependencies of the ionic radii of the M2+ and Ln3+ ions as well as of the order/disorder state. 相似文献
16.
Martin Kirchner Walter Schnelle Frank R. Wagner Rüdiger Kniep Rainer Niewa 《无机化学与普通化学杂志》2005,631(8):1477-1486
Single phase powders of (A19N7)[In4]2 (A = Ca, Sr) and (Ca4N)[In2] were prepared by reaction of melt beads of the metallic components with nitrogen. The crystal structure of (Ca19N7)[In4]2 was refined based on neutron and X‐ray powder diffraction data. The crystal structure of (Sr19N7)[In4]2 was solved from the X‐ray powder pattern. The structure refinements in combination with results from chemical analyses ascertain the compositions. The compounds (A19N7)[In4]2 (A = Ca, Sr) are isotypes of (Ca19N7)[Ag4]2; (Ca19N7)[In4]2 is probably identical to the earlier reported (Ca18.5N7)[In4]2. The crystal structure of the isotypes (A19N7)[In4]2 (A = Ca, Sr; cubic, , Ca: a = 1471.65(3) pm; Sr: a = 1561.0(1) pm) contains isolated [In4] tetrahedra embedded in a framework of edge‐ and vertex‐sharing (A6N) octahedra. Six of these octahedra are condensed by edge‐sharing around one central A2+ ion to form “superoctahedra” (A19N6) which are connected three‐dimensionally via further octahedra by corner‐sharing. The crystal structure of (Ca4N)[In2] (tetragonal, I41/amd, a = 491.14(4) pm, c = 2907.7(3) pm) consists of alternating layers of perovskite type slabs of vertex‐sharing octahedra (Ca2Ca4/2N) and parallel arranged infinite zigzag chains equation/tex2gif-stack-1.gif[In2]. In the sense of Zintl‐type counting the compounds (A2+)19(N3?)7[(In2.125?)4]2 present an electron excess, (Ca2+)4(N3?)[(In2.5?)2] is electron deficient. Metallic properties are supported by electrical resistivity and magnetic susceptibility measurements. The analysis of the electronic structures gives evidence for the existence of homoatomic interactions In–In and significant heteroatomic metal–metal interactions Ca–In which favor the deviations of the title compounds from the (8 – N) rule. 相似文献
17.
New Tin‐rich Stannides of the Systems AII‐Al‐Sn (AII = Ca, Sr, Ba) Four new tin‐rich intermetallics of the ternary systems Ca/Sr/Ba‐Al‐Sn were synthesized from stoichiometric amounts of the elements at maximum temperatures of 1200 °C. Their crystal structures, representing two new types, have been determined using single crystal x‐ray diffraction. Close to the 1:1 composition, the structures of the two isotypic compounds A18[Al4(Al/Sn)2Sn4][Sn4][Sn]2 (overall composition A9M8; A = Sr/Ba, tetragonal, space group P4/mbm, a = 1325.9(1)/1378.6(1), c = 1272.8(2)/1305.4(1) pm, Z = 4, R1 = 0.0430/0.0293) contain three different anionic Sn/Al building units: Isolated Sn atoms (motif I) coordinated by the alkaline earth cations only (comparable to Ca2Sn), linear Sn chains (II), which are comparable to the anions in trielides related to the W5Si3 structure type and finally octahedral clusters [Al4M2Sn4] (III), composed of four Al atoms forming the center plane, two statistically occupied Al/Sn atoms at the apexes and four exohedral Sn attached to Al. Close to the AM2 composition, two isotypic tin‐rich intermetallics A9[Al3Sn2][(Sn/Al)4]Sn6 (overall composition A9M15; A = Ca/Sr; space group C2/m, a = 2175.2(1)/2231.0(2), b = 1210.8(1)/1247.0(1), c = 1007.4(1)/1042.0(2) pm, β = 103.38(1)/103.42(1)°, Z = 2, R1 = 0.0541/0.0378) are formed. Their structure is best described as a complex three‐dimensional network, that can be considered to consist of the building units of the binary border phases too, i.e. linear zig‐zag chains of Sn (motif I) like in CaSn, ladders of four‐bonded Sn/Al atoms (II) like in SrAl2 and trigonal‐bipyramidal clusters [Al3Sn2] (III) also present in Ba3Al5. Despite the complex structures, some statistically occupied Al/Sn positions and the small disorder of one building unit, the bonding in both structure types can be interpreted using the Zintl concept and Wade's electron counting rules when taking partial Sn‐Sn bonds into account. 相似文献
18.
The new ternary rhodium borides Mg3Rh5B2 and Sc3Rh5B2 (P4/mbm, Z = 2; a = 943.4(1) pm, c = 292.2(1) pm and a = 943.2(1) pm, c = 308.7(1) pm, respectively) crystallize with the Ti3Co5B2 type structure. Mg and Sc may in part be substituted by a variety of elements M. For M = Si and Fe, homogeneity ranges were found according to A3–xMxRh5B2 with 0 ≤ x ≤ 1.0 for A = Sc and with x up to 1.5 for A = Mg. Quaternary compounds with x = 1 (A2MRh5B2: A/M in short) were prepared with M = Be, Al, Si, P, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Ga, Ge, As, Sn (Co, Ni only with A = Mg; Sn only with A = Sc; P, As with deficiencies). Single crystal X‐ray investigations show an ordered substitutional variant of the Ti3Co5B2 type in which the M atoms are arranged in chains along [001] with intrachain and interchain M–M distances of about 300 pm and 660 pm, respectively. Measuring the magnetisation (1.7 K–800 K) of the phases Mg/Mn, Sc/Mn, Mg/Fe, and Sc/Fe reveals antiferromagnetic interactions in the first and dominating ferromagnetic intrachain interactions in the remaining ones. Interchain interactions of antiferromagnetic nature are evident in Sc/Mn and Mg/Fe leading to metamagnetism below TN = 130 K, while Sc/Fe behaves ferromagnetically below TC = 450 K. The overall trend towards stronger ferromagnetic interactions with increasing valence electron concentration is obvious. 相似文献
19.
New Tetrapnictidotitanates(IV): Na3M3[TiX4] with M ? Na/Sr, Na/Eu and X ? P, As The four novel tetrapnictidotitanates(IV) Na4Sr2TiP4, Na4Sr2TiAs4, Na4.3Eu1.7TiP4 and Na4.3Eu1.7TiAs4 were prepared from the binary pnictides NaX, M3X, M′X (X ? P, As and M′ ? Sr, Eu) and elementary titanium in tantalum ampoules. The air and moisture sensitive transition metal compounds form dark red hexagonal crystals. They are semiconductors with Eg = 1.8eV (Sr) and Eg = 1.3eV (Eu), respectively. The compounds are isotypic with Na6ZnO4 (space group P63mc (no. 186); hP22; Z = 2; Na4Sr2TiP4; a = 936.8(1) pm, c = 740.5(1) pm; Na4Sr2TiAs4: a = 958.2(1) pm, c = 757.1(1) pm; Na4.3Eu1.7TiP4: a = 929.9(2) pm, c = 732.0(2) pm; Na4.3Eu1.7TiAs4: a = 953.9(1) pm, c = 749.5(1) pm). Main structural units are polar oriented [TiP4]8? and [TiAs4]8? tetrahedral anions with d (Ti? P) = 240.2(3) pm and d (Ti? As) = 248.6(3) pm. 相似文献
20.
About the Crystal Structure of Ba3In2O6 Single crystals of Ba3In2O6 could be prepared by recrystallization of a flux and by solid state reaction in closed platinium tubes, respectively. Ba3In2O6 crystallizes with tetragonal symmetry (space group 14/mmm, a = 4.1868; c = 21.7041 Å, Z = 2). Single crystal X-ray work lead to a crystal structure like La2-xSr1+xCu2O6-δ therefor Ba3In2O6 is a modified member of the Sr3Ti2O7-Type. The coordinations of Ba2+ and In3+ are described and the relations to the Sr3Ti2O7-type are discussed. 相似文献