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1.
A new compound CePt 2+xSb 2−y ( x = 0.125, y = 0.25) was synthesized by arc-melting of the elements. The chemical and structural characterizations were carried out at room temperature on as-cast samples using X-ray diffractometry, metallographic analysis and EDS-microanalysis. According to the results of X-ray single crystal diffraction this antimonide crystallizes in I4 cm space group (no. 108), Z = 32, ρ = 12.19 Mg/m 3, μ = 89.05 mm −1 ( a = 12.5386(3) Å, c = 21.4692(6) Å (crystal I) and a = 12.5455(2) Å, c = 21.4791(5) Å (crystal II)). The structure and composition were confirmed by powder X-ray diffraction ( a = 12.4901(2) Å, c = 21.3620(4) Å) and EDS-microanalysis respectively. Isotypic compounds were observed with La and Pr from X-ray powder diffraction of as-cast alloys at room temperature ( a = 12.6266(4) Å, c = 21.4589(6) Å for LaPt 2+xSb 2−y and a = 12.5184(5) Å, c = 21.4178(7) Å for PrPt 2+xSb 2−y). The CePt 2+xSb 2−y structure is derived from CaBe 2Ge 2 ( a = 2 a0 − 2 b0, b = 2 a0 + 2 b0, c = 2 c0) and comprises a new atomic arrangement with both vacancy on 4(b) pyramidal site and substitution of antimony atoms (X) by platinum (B) in the B–XX–B layers (referring to the subcell structure) forming two B––1/2B1/2XX–3/4B and two X–BB–X layers per cell. The structure of CePt 2+xSb 2−y is compared with those reported before for URh 1.6As 1.9 and CeNi 1.91As 1.94. 相似文献
2.
In our investigation of non-centrosymmetric rare earth sulfides in the La 3AgSnS 7/KBr, LaAlGeS 5/NaBr, HoAlGeS 5/KBr, ErAlGeS 5/NaBr, Er 3AgGeS 7/KBr and La 3NaSnS 7/NaBr systems, five compounds belonging to the R 6B 2C 2Q 14 family have been obtained. These compounds crystallize in the P6 3 space group, and the crystal data are as follows—La 3AgSnS 7: a = 10.3780(15) Å, c = 5.9900(12) Å, Z = 2; La 3Ge 0.25GeS 7: a = 10.2970(15) Å, c = 5.8120(12) Å, Z = 2; Ho 3Ge 0.272(10)GeS 7: a = 9.6480(14) Å, c = 5.7920(12) Å, Z = 2; Er 3Ge 0.330(10)GeS 7: a = 9.5930(14) Å, c = 5.8490(12) Å, Z = 2; La 3Sn 0.25SnS 7: a = 10.2770(15) Å, c = 6.0030(12) Å, Z = 2. Single-crystal analysis indicated that the crystal structures consist of three types of building block: LnS n, MS 4, and AgS 3 (for La 3AgSnS 7) or MS 6 units (for Ln 3M xMS 7, Ln = La, Ho, Er; M = Ge, Sn; 1/4 ≤ x ≤ 1/2), as any other compounds belonging to the R 6B 2C 2Q 14 family. Ln 3M xMS 7 (Ln = La, Ho, Er; M = Ge, Sn; 1/4 ≤ x ≤ 1/2) are deficient compounds with the B sites occupied partly by M(II), and/or M(IV). 相似文献
3.
Two polymorphs (I and II) of Ba 3Sn 2P 4 have been found in the same preparative batch. Both compounds crystallize in the centrosymmetric monoclinic space group P2 1/ c (#14, a = 7.8669(2) Å, b = 19.2378(5) Å, c = 7.8472(2) Å, β = 112.77(1)°, V = 1095.06(5) Å 3, Z = 4, and R/ wR = 0.0303/0.0710 for I; a = 7.8771(3) Å, b = 19.4099(7) Å, c = 7.7040(3) Å, β = 112.44(1)°, V = 1088.67(7) Å 3, Z = 4, and R/ wR = 0.0224/0.0415 for II). Both structures consist of one-dimensional chains separated by Ba 2+ cations. The isolated chain consists of condensed ethane-like [Sn 2P 6] units. In polymorphs I and II, the condensation and connectivity of the [Sn 2P 6] units are quite different. While [Sn 2P 6] units form four- and six-membered rings in I, they form the five-membered rings in II. The electronic structure calculations indicate that semiconducting behavior is expected for both compounds. 相似文献
4.
A new ternary compound Ce(Au,Sb) 2, with a homogeneity range has been observed from X-ray powder diffraction of as cast alloys, a = 4.743–4.712 Å, c = 3.567–3.768 Å. Its crystal structure was investigated by X-ray diffraction from Ce(Au 1−xSb x) 2 ( x = 0.266) single crystal: CAD-4 automatic diffractometer, Mo K radiation, a = 4.7256(6) Å, c = 3.6711(6) Å, P6/ mmm space group, V = 70.997(17) Å 3, Z = 1, ρ = 10.732 Mg/m 3, μ = 76.369 mm −1, R1 = 0.0415, wR2 = 0.0793 for 99 reflections with I > 2 σ( I0). The coordination polyhedron of X (X = 0.734Au + 0.266Sb) atom is a full-capped trigonal prism [XCe 6X 3X 2]. Ce atom is coordinated by 14 atoms: [CeX 12Ce 2]. The compound is isotypic with UHg 2 structure, a deformation derivative of AlB 2 structure type. It forms isostructural compounds with La and Pr. 相似文献
5.
Two ternary alkali earth silver bismuthides, CaAgBi and BaAg 1.837Bi 2, have been synthesized by solid-state reactions of the corresponding metals in welded Nb tubes at high temperature. Their structures have been established by single-crystal X-ray diffraction studies. CaAgBi crystallizes in the hexagonal space group P6 3mc (No.186) with cell parameters of a = b = 4.8113(4) Å, c = 7.8273(9) Å, V = 156.92(3) Å 3, and Z = 2. BaAg 1.837Bi 2 belongs to tetragonal space group P4/ nmm (No.129) with cell parameters of a = b = 4.9202(2) Å, c = 11.628(1) Å, V = 281.50(3) Å 3, and Z = 2. The structure of CaAgBi is of the LiGaGe type, and features a three-dimensional four-connected (3D4C) anionic network with Ca 2+ encapsulated in the channels formed by [Ag 3Bi 3] six-membered rings. BaAg 1.837Bi 2 is isostructural with CaBe 2Ge 2, a variant of the tetragonal ThCr 2Si 2-type structure. Its structure exhibits a three-dimensional anionic network built of (0 0 1) and (0 0 2) puckered [Ag 2Bi 2] layers interconnected via additional Ag–Bi bonds along the c-axis. BaAg 1.837Bi 2 is metallic based on band structure calculations. 相似文献
6.
The crystal structure of new ternary R 3Si 1.25Se 7 (R = Pr, Nd and Sm) compounds (Dy 3Ge 1.25S 7 structure type, Pearson symbol hP22.5, space group P6 3, a = 1.05268 (3) nm, c = 0.60396 (3) nm, RI = 0.0897 for Pr 3Si 1.25Se 7; a = 1.04760 (3) nm, c = 0.60268 (3) nm, RI = 0.0891 for Nd 3Si 1.25Se 7; a = 1.04166 (6) nm, c = 0.59828 (6) nm for Sm 3Si 1.25Se 7) was determined using X-ray powder diffraction. The nearest neighbours of the R and Si atoms are exclusively Se atoms. The latter form distorted trigonal prisms around the R atoms, octahedra around the Si1 atoms and tetrahedra around the Si2 atoms. Tetrahedral surrounding exists for Se1 and Se3 atoms. Six neighbours surround every Se2 atom. 相似文献
7.
The subsolidus phase relation of the system ZnO–Li 2O–MoO 3 has been investigated by X-ray diffraction (XRD) analyses. The phase diagram has been constructed. There are six binary compounds and one ternary compound in this system. The phase diagram comprises nine three-phase regions. The ternary compound Li 2Zn 2(MoO 4) 3 is refined by the Rietveld method. It belongs to an orthorhombic system with space group Pnma and lattice constants a = 5.1114 Å, b = 10.4906 Å, c = 17.6172 Å. 相似文献
8.
Two novel polyphosphides, NaP 5 and CeP 5, were prepared in a BN crucible by the reaction of elemental components under a high pressure of 3 GPa at 800–950 °C. The X-ray structural analysis showed that NaP 5 crystallizes in an orthorhombic space group Pnma with a=10.993(2) Å, b=6.524(1) Å, c=6.903(1) Å, Z=4 and CeP 5 in the monoclinic group P2 1/m with a=4.9143(5) Å, b=9.6226(8) Å, c=5.5152(4) Å, β=104.303(6)°, Z=2. The crystal structure of NaP 5 consists of a three-dimensional framework ∞3[P 5] 1− constructed by P---P bonds among four crystallographically inequivalent phosphorus sites, with large channels hosting the sodium cations, while CeP 5 is a layered compound containing ∞2[P 5] 3− polyanionic layers that are separated by Ce 3+ ions. NaP 5 exhibits the diamagnetic behavior, while the temperature-dependent magnetic susceptibility of CeP 5 essentially follows the Curie–Weiss law. 相似文献
9.
A new mixed-valence iron phosphate Na 1.25Mg 1.10Fe 1.90(PO 4) 3 has been synthesized as single crystals by a flux technique and its structure has been refined from X-ray data to a residual R1 = 0.032. The compound crystallizes in the monoclinic space group C2/ c with the parameters: a = 11.7831(3) Å, b = 12.4740(3) Å, c = 6.3761(2) Å, β = 113.643(2)° and Z = 4. The structure belongs to the alluaudite structural type, and thus it obeys to the X(2)X(1)M(1)M(2) 2(PO 4) 3 general formula. The X(2) and X(1) sites are occupied by sodium while the M(1) and M(2) sites feature a statistical distribution of iron and magnesium. Additional information about the cation distribution has been extracted from a Mössbauer spectroscopy study which confirmed the mixed valency of the compound. A magnetic susceptibility study has also been undertaken and has shown the compound to be antiferromagnetic with a Neel temperature of about 35 K. 相似文献
10.
The crystal structure of La 5Ti 4GaO 17 compound synthesized by heat-treatment of the co-precipitated hydroxy-oxalates has been determined by the X-ray powder diffraction. It was found that crystal structure of La 5Ti 4GaO 17 belongs to the CaLa 4Ti 5O 17-type structure (space group Pmnn, a = 0.3912(1) nm, b = 3.128(1) nm, c = 0.5523(1) nm, Z = 2). The final RW value is equal to 0.081 for 169 independent reflections. 相似文献
11.
The Nd 11Pd 4In 9 compound was prepared by arc melting of pure metals under an argon atmosphere. Crystal structure was refined from X-ray single crystal diffractometer data (space group Cmmm, a = 14.843(3), b = 22.284(3), c = 3.7857(6) Å, Z = 2, RI = 0.0584, 653 F2 values). It has own structure type and together with Mn 2AlB 2, Cr 3AlB 4, Mo 2FeB 2 and Lu 5Ni 2In 4 structure types belongs to homological series based on AlB 2 and CsCl structure types with common formula R m+nM 2nX m. 相似文献
12.
In our investigation of Co-rich alloys in the ternary U–Co–Sn system, we have identified three intermetallic compounds with composition UCo 2Sn, UCo 4Sn and UCo 5Sn, respectively. The existence and the crystal structure of the first compound, already known in the literature, have been confirmed, while the latter two compounds have been identified for the first time. The crystal structure of these compounds was determined by X-ray diffraction methods, performed both on powders (all samples) and single crystals (UCo 4Sn and UCo 5Sn). The crystal data are as follows (lattice constants from Guinier powder patterns): UCo 2Sn [UPd 2Sn-type, orthorhombic, oP16- Pnma, a = 9.402(3), b = 4.321(1), c = 6.615(2) Å], UCo 4Sn [MgCu 4Sn-type, cubic, , a = 6.992(2) Å] and UCo 5Sn [CeCu 4.38In 1.62-type, orthorhombic, oP56- Pnnm, a = 10.250(1), b = 16.012(2), c = 4.837(1) Å]. The physical properties of the compounds have been studied by electric transport (1.5–300 K), heat capacity (1.8–40 K) and magnetic measurements (1.8–300 K). The magnetisation data reveal weakly paramagnetic behaviour (with weak low temperature upturn due to parasitic impurity phases) in all the three alloys and absence of long-range magnetic ordering, despite the presence of uranium and a substantially high concentration of cobalt. The results for UCo 2Sn are in agreement with earlier reports in the literature. The magnitudes of the coefficients of the linear term in the heat capacity and the T2 term in the low temperature resistivity track the room temperature magnetisation. 相似文献
13.
The magnetic properties of DyFe 10−xNi xSi 2 compounds with x = 0, 1, 2, 3, 4, 6, 9 and 10 have been investigated by means of X-ray diffraction and magnetic measurements. Substitution of Ni for Fe leads to a decrease in the lattice constants a, c and the unit-cell volume V. The Curie temperature reaches a maximum of 590 K at x = 2, then decreases strongly for x ≥ 2. The spin reorientations are observed for the compounds with x = 0, 1, 2 and 3. The spin reorientation temperature decreases strongly from 255 to 60 K as the Ni content is increased from x = 0 to 3. Below the spin reorientation temperature, the compounds exhibit ferrimagnetic ordering. For the Ni-rich compounds with x = 9 and 10, the magnetization of the Dy sublattice decreases strongly since the magnetization of the Dy sublattice is strongly affected by the molecular field produced by the 3d sublattice. 相似文献
14.
Ternary R 3Pd 4Ge 4 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 Er 3Pd 3.68(1)Ge 4 compound belongs to the Gd 3Cu 4Ge 4 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 R 3Pd 4Ge 4 compound when R is Nd or Eu was observed. The Nd and Eu containing samples appeared to be multiphase. Ternary phases observed in the Nd 3Pd 4Ge 4 and Eu 3Pd 4Ge 4 alloys and their crystallographic characteristics are the following: NdPd 2Ge 2, CeGa 2Al 2 structure type, space group I4/ mmm, a=4.3010(2) Å, c=10.0633(2) Å (X-ray powder diffraction data); NdPd 0.6Ge 1.4, AlB 2 structure type, space group P6/ mmm, a=4.2305(2) Å, c=4.1723(2) Å (X-ray powder diffraction data); Nd(Pd 0.464(1)Ge 0.536(1)) 2, KHg 2 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, AlB 2 structure type, space group P6/ mmm, a=4.311(2) Å, c=4.235(2) Å; EuPdGe, EuNiGe structure type, space group P2 1/ c, and ternary compound with unknown structure (X-ray powder diffraction data). 相似文献
15.
Single crystals of KCr 0.8Al 0.2Mo 2O 8 were prepared and investigated by the X-ray diffractometer technique. It shows a structure type related to trigonal KAIMo 2O 8, monoclinic NaCrMo 2O 8 or orthorhombic KInMo 2O 8, space group C2h6— C2/ c; a=17.445 Å, b=5.649 Å, c=8.997 Å, β=119.37°; Z=4. KCr 0.8Al 0.2Mo 2O 8 is characterized by isolated MoO 4 tetrahedra, isolated (Cr/Al)O 6 octahedra and a distorted square antiprism around K +. The crystal structure is discussed with respect to those of related compounds. ZusammenfassungEinkristalle von KCr0.8Al0.2Mo2O8 wurden synthetisiert und mit Vierkreisdiffraktometertechnik röntgenographisch untersucht. Sie zeigen einen mit trigonal-KA1Mo2O8, monoklin-NaCrMo2O8 oder orthorhombisch-KlnMo2O8 verwandten Strukturtyp, Raumgruppe C2h6—C2/c; a=17,445 Å, b=5,649 Å, c=8,997 Å, β=119,37°; Z=4. KCr0.8Al0.2Mo2O8 zeichnet sich durch isolierte MoO4-Tetraeder, isolierte (Cr/Al)O6-Oktaeder und ein verzerrtes quadratisches Antiprisma um K+ aus. Die Kristallstruktur wird mit solchen verwandter Verbindungen diskutiert. 相似文献
16.
A new ternary compound of composition LaMg 2Ni has been found and investigated with respect to structure and hydrogenation properties. It crystallizes with the orthorhombic MgAl 2Cu type structure (space group Cmcm, a=4.2266(6), b=10.303(1), c=8.360(1) Å; V=364.0(1) Å 3; Z=4) and absorbs hydrogen near ambient conditions (<200 °C, <8 bar) thereby forming the quaternary metal hydride LaMg 2NiH 7. Neutron powder diffraction on the deuteride revealed a monoclinic distorted metal atom substructure (LaMg 2NiD 7: space group P2 1/ c, a=13.9789(7), b=4.7026(2), c=16.0251(8) Å; β=125.240(3)°, V=860.39(8) Å 3; Z=8) that contains two symmetry independent tetrahedral [NiD 4] 4− complexes with Ni–D bond lengths in the range 1.49–1.64 Å, and six D −anions in tetrahedral metal configuration with bond distances in the ranges 1.82–2.65 Å (Mg) and 2.33–2.59 Å (La). The compound constitutes a link between metallic ‘interstitial’ hydrides and non-metallic ‘complex’ metal hydrides. 相似文献
17.
The crystal structure of the monoclinic phase η-Al 11Cr 2 of the space group C2/ c, a ≈ 1.76 nm, b ≈ 3.05 nm, c ≈ 1.76 nm, β ≈ 90° [L.A. Bendersky, R.S. Roth, J.T. Ramon, D. Shechtman, Metall. Trans. A 22A (1991) 5] has been determined by single-crystal X-ray diffraction. The structure model, refined to a final R value of 0.0441, has the composition of Al 83.8Cr 16.2. a = 1.77348(10) nm, b = 3.04555(17) nm, c = 1.77344(10) nm, monoclinic angle β = 91.0520(12)°. There are 80 (66Al + 14Cr) independent atomic positions in a unit cell, of which all Cr atom sites and 8 Al atom sites have icosahedral coordination. These icosahedra are interconnected forming icosahedral chains along , (1 0 1) icosahedral layer blocks as well as a three-dimensional icosahedral structure. 相似文献
18.
Investigations of phase relations in the Ba-rich part of the In 2O 3–BaO(CO 2)–CuO pseudo-ternary system at 900 °C have revealed the existence of new indium–copper oxycarbonate – Ba 4In 0.8Cu 1.6(CO 3) 0.6O 6.2. Rietveld refinement of the X-ray powder diffraction data combined with infrared studies gives evidence that this phase is a oxycarbonate crystallising in the tetragonal structure (space group I4/ mmm) with unit cell parameters: a=4.0349(1) Å and c=29.8408(15) Å. In the binary part of the In 2O 3–BaO(CO 2) system we have identified the occurrence of Ba 4In 2−x(CO 3) 1+xO 6−2.5x oxycarbonate solid solution showing a crystal structure also described by I4/ mmm space group, but with the unit cell parameters: a=4.1669(1) Å and c=29.3841(11) Å for x=1. The existence range of this phase, −0.153< x<0.4, includes chemical compositions of earlier found phases: Ba 5In 2+xO 8+0.5x with 0≤ x≤0.45 (known as the -solid solution), as well as the binary Ba 4In 2O 7 phase. The crystal structures of both new oxycarbonates are isomorphic and related to n=3 member of the Ruddlesden–Popper family. 相似文献
19.
The subsolidus phase relationships of ternary system Na 2O–ZnO–WO 3 have been investigated by X-ray diffraction (XRD) and differential thermal analyzer (DTA). All the samples were synthesized in the temperature range from 530 to 850 °C in air. There are one ternary compound and five binary compounds in the Na 2O–ZnO–WO 3 system, which can be divided into eight three-phase regions. The crystal structure of the ternary compound Na 3.6Zn 1.2(WO 4) 3 is determined by single-crystal structure analysis method. It belongs to triclinic system with space group and lattice constants a = 7.237 (5) Å, b = 9.172 (6) Å, c = 9.339 (6) Å and = 94.920 (4)°, β = 105.772 (9)°, γ = 103.531 (8)°, Z = 2. DTA analyses indicate that the compound Na 2WO 4 is not suitable to be the flux for ZnO crystal growth below 1250 °C, since no liquidus was observed in the system before 1250 °C. 相似文献
20.
The crystal structure of intermetallic compound Gd 6Cr 4Al 43 has been investigated by means of X-ray diffraction data (Ho 6Mo 4Al 43 structure type, space group P6 3/ mcm, Pearson symbol hP106, a = 10.9144(7) Å, c = 17.7361(13) Å). SQUID magnetic measurements carried out for the title compound point to the existence of two antiferromagnetic phase transitions observed at TN1 = 19.0(1) K and TN2 = 6.8(1) K, respectively. 相似文献
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