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1.
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
2.
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
3.
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
4.
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
5.
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
6.
The structural properties of the compounds in the tin-rich part of the dysprosium–tin system have been studied by X-ray powder diffraction. The crystal structures of six compounds DySn 2+x (0 < x < 1) have been characterized. There are four compounds with known structural types: DySn 2 with the ZrSi 2 structure, Dy 3Sn 7 with the Gd 3Sn 7 structure, Dy 2Sn 5 with the Er 2Ge 5 structure, DySn 3 with the DyGe 3 structure and two compounds characterized by new body-centred orthorhombic types ( Immm): Dy 5Sn 11 ( a = 4.411 Å, b = 42.50 Å and c = 4.328 Å) and Dy 5Sn 13 ( a = 4.341 Å, b = 48.05 Å and c = 4.405 Å) which result from various insertions of AuCu 3 and Po slabs into the ZrSi 2 structure. The relationships and structural evolution are discussed. 相似文献
7.
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
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 hydrothermal reaction of 2,5-pyridinedicarboxylic acid (H 2PDC), diethylene triamine and In(NO 3) 3·4.5H 2O gave rise to a two-dimensional (2D) coordination polymer In(OH)(2,5-PDC). This compound crystallizes in the orthorhombic space group Iba2, with cell parameters, a = 12.656(3) Å, b = 20.114(4) Å, c = 6.2216(1) Å, V = 1583.9(5) Å 3 and Z = 8. Its structure contains one-dimensional In–O–In–O– chains, which are further linked by 2,5-PDC ligands into a 2D supramolecular neutral framework. The adjacent 2D layers are parallel with each other and construct a three-dimensional framework via hydrogen bands. At room temperature, the compound exhibits intense photoluminescence. On the basis of the results of TG/DTA analyses, the structure is thermally stable up to 390 °C. 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.
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
13.
LEAlB 14 (orthorhombic, Imam) (LE = Li, Mg) crystals were grown using metal salts (Li 2CO 3, LiF, LiI, MgO, MgF 2, MgI 2) and crystalline boron from a high-temperature aluminium metal flux. The growth conditions for growing LEAlB 14 were established using the starting mixtures of B/LE = 2.0, and Al metal was added to each mixture at a mass ratio of 1:15–20. LEAlB 14 crystals from the Al-self flux using metal salts could be obtained from all the different salts. The maximum dimensions of LiAlB 14 and MgAlB 14 crystals were approximately 18 and 12 mm for the crystals obtained from LiF and MgF 2. The unit-cell parameters of as-grown LEAlB 14 are as follows: for LiAlB 14, obtained from LiF, a = 0.5846 (2) nm, b = 0.8144 (2) nm, c = 1.0355 (3) nm, V = 0.4930 (2) nm 3: for MgAlB 14, obtained from MgF 2, a = 0.5845 (2) nm, b = 0.8114 (2) nm, c = 1.0330 (3) nm, V = 0.4899 (3) nm 3. Microhardness, oxidation resistance and magnetic susceptibility of these materials are described in detail. 相似文献
14.
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
15.
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
16.
Structural studies were performed for the ternary RIr 3B 2 compounds (R=Ce and Pr) from as cast samples. The crystal structure of the ternary boride CeIr 3B 2 (CeCo 3B 2 structure type, space group P6/ mmm, a=5.520(3) Å, c=3.066(2) Å, Z=1, V=80.91 Å 3, ρ x=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 PrIr 3B 2 was found to be isostructural with the CeIr 3B 2 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
17.
Light yellow single crystals of potassium nitridoditungstate (K 6W 2N 4O 3) and pale single crystals of potassium digermanate (K 6Ge 2O 7) were obtained by the reaction of the metal oxides WO 3 (molar ratio, 1 : 15.7) or GeO 2 (molar ratio, 1 : 2) in alkali metal amide melts in an autoclave at 530–600 °C for 6–8 days. Colourless single crystals of rubidium digermanate (Rb 6Ge 2O 7) were prepared by the reaction of GeO 2 with rubidium amide (molar ratio, 1 : 2) in ammonia at 350 °C in a high-pressure autoclave (H. Jacobs and D. Schmidt, in E. Kaldis (ed.), High-pressure Ammonolysis in Solid State Chemistry, Current Topics in Materials Science, Vol. 8, North Holland, Amsterdam, 1981, p. 379) ( p( NH3) = 5.5 kbar) for 10 days. In all three cases other nitrogen-containing products were present. The structures of the title compounds were determined on the basis of single-crystal data. They are isotypic or structurally closely related to each other: K6W2N4O3: P21/n, a = 6.720(2) Å, b = 9.473(1) Å, c = 9.581(2) Å, β = 91.99(2)°, Z = 2, R/Rw = 0.040/0.048, N(I) > 3σ(I) 2057, N(Var.) = 71. K6Ge2O7: Pn, a = 6.529(2) Å, b = 9.079(4) Å, c = 9.162(6)Å, β = 91.85(4)°, Z = 2, R/Rw = 0.022/0.024, N(I) 3σ(I) = 1486, N(Var.) = 135. Rb6Ge2O7: P21/n, a = 6.839(4) Å, b = 9.437(6) Å, c = 9.460(6) Å, β = 91.53(5)°, Z = 2, R/Rw = 0.061/0.074, N(I) 3σ(I) = 1055, N(Var.) = 71. 相似文献
18.
The new compound Li 2VGeO 5 with a layered structure has been synthesized at 580 °C via the hydrothermal method. The compound crystallizes in the space group P4/ n of the tetragonal system with two formula units in a cell of dimensions a=6.5187(9) Å, c=4.5092(9) Å ( T=298 K), V=191.61(5) Å 3. The structure is composed of layers made of repeating [(VO 5)(GeO 4)] 1− units. Li + ions reside between the layers. The magnetic susceptibility data show an antiferromagnetic coupling below 5 K with C=0.47 emu K mol −1, and θ=−13 K with μ eff=1.89 μB for each Li 2VGeO 5 unit. 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.
A new Mg-containing quaternary nitride, Sr 3GeMgN 4, was obtained as single crystals from constituent elements in molten Na. It crystallizes in space group Pnna (No. 52) with a=5.939(1) Å, b=10.320(2) Å, c=9.618(2) Å, and Z=6. It is isostructural with Sr 3Ga 2N 4, both of which contain one-dimensional chains of edge-sharing tetrahedra. 相似文献
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