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1.
A. V. Morozkin 《Journal of Alloys and Compounds》2003,360(1-2):L7-L8
Results of a powder X-ray diffraction investigation of new ternary compounds are reported. The compounds Y6CoBi2 [a=0.8312(1) nm, c=0.4144(1) nm], Ho6CoBi2 [a=0.8246(2) nm, c=0.4095(1) nm], and Tm6CoBi2 [a=0.8155(2) nm, c=0.4066(1) nm] crystallize in the hexagonal Zr6CoAs2-type structure (space group P6b2m No. 189). The Zr6CoAs2-type structure is a superstructure of the Fe2P-type structure. 相似文献
2.
Using X-ray powder and single crystal diffraction, the crystal structures of the Nd(Ru0.6Ge0.4)2 and ErRuGe compounds were investigated. The compounds belong to the KHg2 and TiNiSi type structure, respectively. 相似文献
3.
Ternary R3Pd4Ge4 samples (R=Nd, Eu, Er) were investigated by means of X-ray single crystal (four circle diffractometer Philips PW1100, MoK radiation) and powder diffraction (MX Labo diffractometer, CuK radiation). The Er3Pd3.68(1)Ge4 compound belongs to the Gd3Cu4Ge4 structure type, space group Immm, a=4.220(2) Å, b=6.843(2) Å, c=14.078(3) Å, R1=0.0484 for 598 reflections with Fo>4σ(Fo) from X-ray single crystal diffraction data. No ternary R3Pd4Ge4 compound when R is Nd or Eu was observed. The Nd and Eu containing samples appeared to be multiphase. Ternary phases observed in the Nd3Pd4Ge4 and Eu3Pd4Ge4 alloys and their crystallographic characteristics are the following: NdPd2Ge2, CeGa2Al2 structure type, space group I4/mmm, a=4.3010(2) Å, c=10.0633(2) Å (X-ray powder diffraction data); NdPd0.6Ge1.4, AlB2 structure type, space group P6/mmm, a=4.2305(2) Å, c=4.1723(2) Å (X-ray powder diffraction data); Nd(Pd0.464(1)Ge0.536(1))2, KHg2 structure type, space group Imma, a=4.469(2) Å, b=7.214(2) Å, c=7.651(3) Å, R1=0.0402 for 189 reflections with Fo>4σ(Fo) (X-ray single crystal diffraction data); Eu(Pd,Ge)2, AlB2 structure type, space group P6/mmm, a=4.311(2) Å, c=4.235(2) Å; EuPdGe, EuNiGe structure type, space group P21/c, and ternary compound with unknown structure (X-ray powder diffraction data). 相似文献
4.
Structural studies were performed for the ternary RIr3B2 compounds (R=Ce and Pr) from as cast samples. The crystal structure of the ternary boride CeIr3B2 (CeCo3B2 structure type, space group P6/mmm, a=5.520(3) Å, c=3.066(2) Å, Z=1, V=80.91 Å3, ρx=15.154 g cm−3) was refined to R1=0.0470, wR2=0.1240 from single-crystal X-ray diffraction data. The new ternary boride PrIr3B2 was found to be isostructural with the CeIr3B2 compound. Its lattice parameters a=5.5105(2) Å, c=3.1031(1) Å were obtained from a Rietveld refinement of X-ray powder diffraction data. 相似文献
5.
V. V. Lisnyak N. V. Stus P. Popovich D. A. Stratiychuk Ya. Filinchuk V. M. Davydov 《Journal of Alloys and Compounds》2003,360(1-2):81-84
A novel molybdenum diphosphate, Mo1.3O(P2O7), was obtained by electrochemical lithium deintercalation. The diphosphate crystallises in space group I2/a with the lattice parameters a=22.88(1), b=22.94(2), c=4.832(1) Å, γ=90.36°, Z=8. Its original framework is built up from MoO6 octahedra, P2O7 groups and also from MoO4, Mo2O4 and Mo3O8 units containing Mo2 and Mo3 clusters. These polyhedra delimit large octagonal and z-shaped tunnels running along c, in which the inserted cations may be located. 相似文献
6.
P. Salamakha O. Sologub A. P. Gonalves M. Almeida 《Journal of Alloys and Compounds》2003,360(1-2):131-136
The crystal structure of a new ternary boride Ce2Ir5B2, space group
, a=5.477(2) Å, c=31.518(5) Å, Z=6, V=818.79 Å, was refined down to R=0.0484, wR2=0.1211 from single crystal X-ray diffraction data. This is the first representative of a new structure type of intermetallic compounds (an ordered variant of the binary Er2Co7 compound). The structure of Ce2Ir5B2 is the stacking variant of the MgCu2- and CeCo3B2-type slabs and belongs to the structural series with the general formula R2+nM4+3nX2n (n=2). 相似文献
7.
Powder X-ray diffraction results and macroscopic magnetic properties of new ternary RRh5Ge3 compounds (R=Sm, Gd, Tb) are reported. The compounds SmRh5Ge3 (a=2.2744(4) nm, c=0.3888(1) nm), GdRh5Ge3 (a=2.2711(5) nm, c=0.3872(1) nm) and TbRh5Ge3 (a=2.2628(7) nm, c=0.3851(1) nm) crystallize in the hexagonal SmRh5Ge3-type structure (space group P63/m; No. 176). The GdRh5Ge3 and TbRh5Ge3 compounds are Curie–Weiss paramagnets down to 5 K. 相似文献
8.
《Journal of Alloys and Compounds》2003,360(1-2):76-80
Powder X-ray and neutron diffraction and magnetic measurements have been performed on R2RhSi3 (R=Ho and Er) compounds at low temperatures. The compounds crystallize in a derivative of the hexagonal AlB2-type structure. The crystal structure parameters have been refined on the basis of the X-ray and neutron diffraction patterns collected in the paramagnetic region. These compounds are antiferromagnets with Néel temperatures of 5.2 K for Ho2RhSi3 and 5 K for Er2RhSi3. Both compounds exhibit collinear magnetic structures, described by the propagation vector k=(1/2,0,0) for Ho2RhSi3 and k=(0,0,0) for Er2RhSi3. This magnetic order is stable in the temperature range between 1.5 K and the Néel temperature. 相似文献
9.
H. Samata M. Kai T. Uchida M. Ohtsuka G. Tanaka S. Sawada T. Taniguchi Y. Nagata 《Journal of Alloys and Compounds》2003,350(1-2):77-85
Crystals of Ba3NaRu2O9−δ (δ≈0.5) and Ba3(Na, R)Ru2O9−δ (R=Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm and Yb) were grown by an electrochemical method, and their crystallographic, magnetic, and electric properties were studied. All crystals have a hexagonal structure of space group P63mmc. Ba3NaRu2O9−δ and Ba3(Na, R)Ru2O9−δ (except Ce) have a negative asymptotic Curie temperature suggesting the existence of an antiferromagnetic order; however, they are paramagnetic at temperatures above 1.7 K. Ba3NaRu2O9−δ has an effective magnetic moment Peff of 0.91 μB, while Peff of Ba3(Na, R)Ru2O9−δ (except Ce) reflects the large free-ion moment
of the rare earth ions. Ba3(Na, Ce)Ru2O9−δ shows peculiar magnetic behavior that differs from the magnetism of other Ba3(Na, R)Ru2O9−δ crystals. The resistivity of all crystals exhibits an activation-type temperature dependence with an activation energy in the range of 0.10.2 eV. 相似文献
10.
Y. Filinchuk V.V. Lisnyak D.A. Stratiichuk N.V. Stus 《Journal of Alloys and Compounds》2008,463(1-2):124-128
The crystal structure of sodium pentamolybdyl tetradiphosphate Nax(MoO)5(P2O7)4 has been determined from synchrotron diffraction data collected at 293 K on two microcrystals. The compound crystallizes in a monoclinic space group I 1 1 2/a (no. 15, setting 11), with unit cell parameters a = 22.905(3), b = 23.069(2), c = 4.8537(2) Å, γ = 90.641(9)° and a = 22.898(3), b = 23.056(2), c = 4.8551(2) Å, γ = 90.82(1)°, for crystals I and II, respectively. The structure is pseudo-tetragonal, and the crystals are pseudo-merohedrally twinned by 90° rotation around the c-axis. The structure closely resembles the previously reported Li-deintercalated Mo1.3OP2O7 [V.V. Lisnyak, N.V. Stus, P. Popovich, D.A. Stratiychuk, Ya. Filinchuk, V.M. Davydov, J. Alloys Compd. 360 (2003) 81–84]. Comparison of the two structures led us to conclude that the Mo2 and Mo3 clusters were erroneously identified in Mo1.3OP2O7. A revised structure of Mo1.3OP2O7 contains a fully occupied oxygen site instead of the 16% occupied Mo(2) site, thus the revised formulae for the Li-deintercalated compound is (MoO)5(P2O7)4. In both structures, the (MoO)5(P2O7)4 framework strongly resembles the one in the earlier reported Ag(MoO)5(P2O7)4, while the location of Na and Ag atoms differ. 相似文献
11.
Bo Zhou Zhengfei Gu Junqin Li Gang Cheng Jun Cheng Chengfu Xu Lei Ma 《Journal of Alloys and Compounds》2007,430(1-2):132-135
A portion of the isothermal section (1173 K) of the phase diagram of the Gd–Co–Al ternary system (up to 33.3 at.% Gd) were investigated by X-ray diffraction (XRD), scanning electron microscopy (SEM) and energy dispersion spectroscopy (EDS) techniques. Fourteen single-phase regions (including solid solution regions of the binary compounds), twenty-five two-phase regions and twelve three-phase regions were found to exist at this isothermal section. In the GdCo2–GdAl2 system, the existence of the GdCo0.74Al1.26 phase is identified and it has a composition range of 30–45 at.% Al, the maximum solid solubility of Al in GdCo2 is about 15 at.%, and Co in GdAl2 is about 16 at.%. Besides, the maximum solid solubility of Al in Co, Gd2Co17 and GdCo5 is about 6, 17 and 25 at.%, respectively, the maximum solid solubility of Gd in Co, CoAl is below 2 at.% and the solid solubility range is from 47 to 61 at.% Al in CoAl phase. In this work, no new ternary compounds were observed. 相似文献
12.
Neutron diffraction data show that PrMn0.5Sn1.83 has a defect CeNiSi2-type crystal structure and orders antiferromagnetically below TN=16 K. The Pr magnetic moments are coupled antiferromagnetically according to the τ6 mode. 相似文献
13.
Ewa Talik Marie-Emilie Lucas Wojciech Suski R. Tro 《Journal of Alloys and Compounds》2003,350(1-2):72-76
The XPS electronic structures of the AFe4Al8 (A=Sc, Y, U, Th) single crystals were measured. The valence band of UFe4Al8 exhibits domination of the U 5f states at the Fermi level, while for the other AFe4Al8 compounds the valence states are shifted by 0.5 eV toward higher binding energy. The multiplet structure of the U 4f and Th 4f states was analyzed in comparison with the U 4f states of U3Ge5 and UNiSb2. 相似文献
14.
P. K. Siwach H. K. Singh N. Khare A. K. Singh O. N. Srivastava 《Journal of Alloys and Compounds》2003,350(1-2):56-61
A new manganite type CMR material, La0.7Hg0.3MnO3 has been successfully synthesized and has been found to exhibit magnetoresistance (≈9%) at low fields (≈1.5 kG). The synthesis has been carried out through a solid state reaction route consisting of the formation of La0.7MnO3 followed by diffusion of Hg leading to La0.7Hg0.3MnO3. The as grown samples are polycrystalline and correspond to an orthorhombic unit cell with the lattice parameters; a=5.5183 Å, b=5.6383 Å and c=7.5368 Å. The typical grain size as revealed by scanning electron microscopy is in the range of 0.5–2 μm. The ρ–T behaviour shows a peak at TIM=227 K. The ρ–T behaviour above this temperature corresponds to that of an insulator and below this to that of a metal. The ρ–T behaviour remains unaltered when a magnetic field (Hdc=1.5 kG) is applied. However, with this magnetic field a drop in the resistivity is observed up to 77 K. At room temperature the magnetoresistance ratio (MRR) is too small but it steadily increases as the temperature is decreased. Thus, MRRs at 227.13 and 77 K are 3.41 and 9.05%, respectively, in an applied field of Hdc=1.5 kG. At a given temperature the variation in MRR with field Hdc is rapid at lower field values (Hdc<1.2 kG) and scales linearly for higher field values (Hdc>1.2 kG). It may be mentioned that the present work on the synthesis and magnetoresistance behaviour of La0.7Hg0.3MnO3, is the first of its type. 相似文献
15.
N.D. Dahale Meera Keskar N.K. Kulkarni K.D. Singh Mudher 《Journal of Alloys and Compounds》2007,440(1-2):145-149
In Na–U(IV)–Mo–O system, two quaternary compounds Na2U(MoO4)3 and Na4U(MoO4)4 were prepared by solid state reactions of Na2MoO4, UMoO5 and MoO3 in the required stoichiometric ratio at 500 °C in evacuated sealed quartz ampoules. The crystal structure of both the compounds were derived from X-ray powder diffraction data in the tetragonal system by Rietveld profile method. Na2U(MoO4)3 has scheelite structure, whereas Na4U(MoO4)4 has scheelite superlattice structure.
TG curves of Na2U(MoO4)3 and Na4U(MoO4)4 did not show any significant weight change up to 750 °C in an inert atmosphere. During the heating cycle in an inert atmosphere, DTA curves of Na2U(MoO4)3 and Na4U(MoO4)4 showed endothermic peaks due to the melting of the compounds at 740 °C and 730 °C, respectively. Na2U(MoO4)3 and Na4U(MoO4)4, when heated in air atmosphere at 1200 °C, decomposed to form Na2U2O7 which was confirmed by weight loss calculation and XRD. 相似文献
16.
P. Salamakha A. P. Gonalves O. L. Sologub M. Almeida 《Journal of Alloys and Compounds》2003,360(1-2):61-68
The crystal structure of the ternary boride Y2Pd14B5, space group I41/amd, a=8.484(2) Å, c=16.490(3) Å, V=1186.98 Å3, Z=4, was refined down to R=0.0475, wR2=0.1276 from single crystal X-ray diffraction data. Two types of coordination for boron atoms were observed: the coordination sphere for the B1 atom is a trigonal prism with one additional atom; the B2 atom has only four neighboring atoms which form a square. No boron–boron contact was observed. Analysis of the Y2Pd14B5 crystal structure shows the existence of a correlation between this structure and the Sc4Ni29B10 structure type. Magnetization and AC susceptibility measurements indicate that there is no superconducting or magnetic transition in Y2Pd14B5 down to 2 K. 相似文献
17.
A. V. Morozkin 《Journal of Alloys and Compounds》2003,360(1-2):L1-L2
A powder X-ray diffraction investigation of the new ternary compounds Zr6CoAs2-type R6MnSb2 and R6MnBi2 (R=Y, Lu, Dy, Ho) is reported. The compounds Ho6MnSb2 (a=0.8070(2) nm, c=0.4230(1) nm), Lu6MnSb2 (a=0.7930(1) nm, c=0.4173(1) nm), Y6MnBi2 (a=0.8242(1) nm, c=0.4292(1) nm), Dy6MnBi2 (a=0.8211(1) nm, c=0.4286(1) nm), Ho6MnBi2 (a=0.8164(1) nm, c=0.4250(1) nm) and Lu6MnBi2 (a=0.8019(2) nm, c=0.4185(1) nm) crystallize in the hexagonal Zr6CoAs2-type structure (space group P6b2m No. 189). The Zr6CoAs2-type structure is a superstructure of the Fe2P-type structure. 相似文献
18.
O. L. Sologub K. Hiebl P. S. Salamakha H. Ipser 《Journal of Alloys and Compounds》2003,360(1-2):54-60
The crystal structure of a new series of ternary rare-earth platinum borides RPt3B (R=La, Pr, Nd) has been studied by X-ray powder diffraction analyses from the ‘as-cast’ alloys. The tetragonal CePt3B structure type, space group P4mm (No. 99), has been confirmed for all compounds. Rietveld refinements for the two compounds, PrPt3B and NdPt3B, were performed. LaPt3B is a temperature-independent Pauli-type paramagnet from room temperature down to 4 K. PrPt3B orders antiferromagnetically at TN=15 K followed by a ferromagnetic spin flip at TC=5 K, whereas NdPt3B exhibits an antiferromagnetic spin alignment at a Néel temperature TN=7 K. The temperature dependence of the electrical resistivity, ρ(T), reflects the metallic character of these compounds. Furthermore the characteristic changes of slope of ρ(T) plots prove the magnetic transitions. 相似文献
19.
X.Z. Li X.L. Chen L. Wu Y.G. Cao T. Zhou Y.P. Xu 《Journal of Alloys and Compounds》2004,370(1-2):53-58
A new modification of the compound Ba3YB3O9, β phase, has been attained through solid phase transition from phase at 1125–1134 °C. β-Ba3YB3O9 crystallizes in the hexagonal space group
with cell parameters a=13.0529(8) Å, c=9.5359(9) Å. The crystal structure of -Ba3YB3O9 has been determined from powder X-ray diffraction (XRD) data. The refinement was carried out using the Rietveld methods and the final refinement converged with Rp=8.8%, and Rwp=11.8% with Rexp=5.65%. In its structure, the isolated [BO3]3− anionic groups are parallel to each other and distributed layer upon layer along the c-axis. The Y atoms are six-coordinated by the O atoms to form octahedra. The result of IR spectrum confirmed the existence of [BO3]3− triangular groups. 相似文献
20.
C. Rizzoli P. S. Salamakha O. L. Sologub G. Bocelli 《Journal of Alloys and Compounds》2002,340(1-2):146-150
The crystal structure of the new ternary stannide YbNi2−xSn [space group P63/mmc (N 194), z=4] was investigated using single crystal X-ray diffraction data (automatic single crystal diffractometers Philips PW1100 and Bruker SMART CCD, Mo K radiation). Three crystals with different composition YbNi1.695Sn [a=4.424(4) Å, c=15.232(6) Å, V=258.2(4) Å3, ρ=10.066 g cm−3, μ=57.32 mm−1], YbNi1.705Sn [a=4.424(5) Å, c=15.179(7) Å, V=257.3(4) Å3, ρ=10.116 g cm−3, μ=57.59 mm−1] and YbNi1.745Sn [a=4.303(6) Å, c=16.001(9) Å, V=256.7(5) Å3, ρ=10.199 g cm−3, μ=58.00 mm−1] were refined to R=0.0494, wR2=0.1330, to R=0.0782, wR2=0.1916 and to R=0.0643, wR2=0.1460, respectively. The compounds belongs to a new structure type of intermetallic compounds and are formed from two hypothetical structures YbNi1.5Sn (space group P63/mmc, z=4) and YbNi2Sn (space group P63/mmc, z=4) containing segments of the MnCu2Al, ZrBeSi and ZrPt2Al structures. 相似文献