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1.
The clathrate‐I phase Cs8–xGe44+y2–y (space group Pm$\bar{3}$ n) was prepared by high‐pressure high‐temperature reactions of Cs4Ge4 and α‐Ge. Different reaction conditions were found to have a strong influence on the lattice parameter of the clathrate‐I phase ranging from 10.8070(2) Å to 10.8493(3) Å. A single crystal with composition Cs8Ge44.40(2)1.60(2) was obtained from a sample with a = 10.8238(2) Å (niobium ampoule, p = 3.4 GPa, Tmax = 1400 °C). Structure analysis based on X‐ray single crystal data shows unambiguously an excess of germanium atoms with respect to the electron balanced composition Cs8Ge442 on basis of the Zintl concept.  相似文献   

2.
New Germanides with an Ordered Variant of the Ce3Pt4Ge6 Type of Structure – The Compounds Ln3Pt4Ge6 (Ln: Pr–Dy) Six new germanides Ln3Pt4Ge6 with Ln = Pr–Dy were synthesized by heating mixtures of the elements at 900 °C, annealing the inhomogeneous powders at 1050‐1100 °C for six days and then cooling down from 700 °C in the course of two months. The crystal structures of Pr3Pt4Ge6 (a = 26.131(5), b = 4.399(1), c = 8.820(2) Å), Sm3Pt4Ge6 (a = 25.974(3), b = 4.356(1), c = 8.748(1) Å), and Dy3Pt4Ge6 (a = 26.079(5), b = 4.311(1), c = 8.729(2) Å) were determined by single crystal X‐ray methods. The compounds are isotypic (Pnma, Z = 4) and crystallize with an ordered variant of the Ce3Pt4Ge6 type of structure (Cmcm, Z = 2) consisting of CaBe2Ge2‐ and YIrGe2‐analogous units. The platinum atoms are located in distorted square pyramids of germanium atoms and build up with them a three‐dimensional network. The coordination polyhedra of the platinum and germanium atoms around the rare‐earth metal atoms are pentagonal and hexagonal prisms. These are completed by some additional atoms resulting in coordination numbers of 14 and 15 respectively. The other germanides were investigated by powder methods resulting in the following lattice constants: a = 26.067(6), b = 4.388(1), c = 8.800(2) Å for Ln = Nd; a = 25.955(7), b = 4.337(1), c = 8.728(2) Å for Ln = Gd; a = 25.944(5), b = 4.322(1), c = 8.698(2) Å for Ln = Tb. The atomic arrangement of Ln3Pt4Ge6 is compared with the well‐known monoclinic structure of Y3Pt4Ge6.  相似文献   

3.
The ternary rare‐earth germanium antimonides RE12Ge7?xSb21 (RE=La–Pr; x=0.4–0.5) are synthesized by direct reactions of the elements. Single‐crystal X‐ray diffraction studies indicate that they adopt a new structure type (space group Immm, Z=2, a=4.3165(4)–4.2578(2) Å, b=15.2050(12)–14.9777(7) Å, c=34.443(3)–33.9376(16) Å in the progression from RE=La to Pr), integrating complex features found in RE6Ge5?xSb11+x and RE12Ga4Sb23. A three‐dimensional polyanionic framework, consisting of Ge pairs and Sb ribbons, outlines large channels occupied by columns of face‐sharing RE6 trigonal prisms. These trigonal prisms are centered by additional Ge and Sb atoms to form GeSb3 trigonal‐planar units. A bonding analysis attempted through a Zintl–Klemm approach suggests that full electron transfer from the RE atoms to the anionic substructure cannot be assumed. This is confirmed by band‐structure calculations, which also reveal the importance of Ge? Sb and Sb? Sb bonding. Magnetic measurements on Ce12Ge6.5Sb21 indicate antiferromagnetic coupling but no long‐range ordering down to 2 K.  相似文献   

4.
Crystal Structures of CaBe2Ge2 and CeMg2Si2 analogous Units: The Phosphides LnPt2P2?x (Ln: La, Sm) Single crystals of LaPt2P1.44 (a = 4.174(1), c = 19.212(5) Å) were grown by reaction of vaporous phosphorus with LaPt2 at 1050 °C during two weeks, whereas SmPt2P1.50 (a = 4.131(1), c = 19.086(4) Å) was synthesized by heating mixtures of the elements at 900 and 1100 °C (60 h) and annealing at 1050 °C (300 h). Both phosphides were investigated by single crystal X‐ray methods. Their crystal structures (I4/mmm; Z = 4) consist of CaBe2Ge2 and CeMg2Si2 analogous units alternating with each other along [001]. The positions of the P1 atoms are occupied incompletely causing the deviation to the 1:2:2 stoichiometry. Another compounds LnPt2P2?x were studied by X‐ray powder diffraction resulting in the following lattice constants: a = 4.150(1), c = 19.132(5) Å for CePt2P2–x, a = 4.137(1), c = 19.085(4) Å for PrPt2P2?x, and a = 4.127(1), c = 19.040(2) Å for NdPt2P2?x.  相似文献   

5.
Crystallization of chloro­(2,2′:6′,2′′‐terpyridine)platinum(II) chloride from dimethyl sulfoxide yields a red polymorph, [PtCl(C15H11N3)]Cl·C2H6OS, (I), which exhibits stacking along the a axis through pairs of Pt⋯Pt(−x, −y, −z) inter­actions of 3.3155 (8) Å. The cations are further associated through close Pt⋯Pt(1 − x, −y, −z) distances of 3.4360 (8) Å. Recrystallization from water gives a mero­hedrally twinned yellow–orange dihydrate form, [PtCl(C15H11N3)]Cl·2H2O, (II), with pairwise short Pt⋯Pt(1 − x, 2 − y, −z) contacts of 3.3903 (5) Å but no long‐range stacking through the crystals. Inter­pair Pt⋯Pt(−x, 2 − y, −z) distances between cation pairs in the hydrate are 4.3269 (5) Å.  相似文献   

6.
Hydrothermal reactions of MoO3, CuO, and pyrazine‐2‐carboxylic acid (Hpzca) resulted in two polymeric complexes, {[Cu5(pzca)6(H2O)4][Mo8O26]}n ( 1 ; pzca=pyrazine‐2‐carboxylate) and [Mo3Cu2O10(pz)]n ( 2 ; pz=pyrazine). The former crystallized in the monoclinic space group P21/c with a=10.805(3) Å, b=13.061(5) Å, c=13.337(10) Å, β=90.20(4)°, V=2729(2) Å3, and Z=2. The later crystallized in the orthorhombic space group Pnma with a=12.385(2) Å, b=7.6044(9) Å, c=12.7880(14) Å, V=1204.4(2) Å3, and Z=4. X‐Ray diffraction analysis revealed that 1 possesses a two‐dimensional wave‐like structure, formed from a zigzag one‐dimensional chain, and 2 is a three‐dimensional network structure formed from a one‐dimensional chain and a pz bridging ligand. The temperature‐dependent magnetic behavior of 1 was studied.  相似文献   

7.
《Solid State Sciences》2012,14(4):426-429
The single crystal of Fe6−xGayGe5−y (x ∼0.5, y = 1.3(1)) has been obtained from arc-melting of the elements and its crystal structure has been investigated by single-crystal X-ray diffraction analysis. The compound crystallizes in the hexagonal space group P63/mmc (No. 194) with a = 8.0346(2) Å, c = 5.007(1) Å, Z = 1 and adopts the Ti6Sn5 structure type with a refined composition of Fe5.52(12)(Ga/Ge)5. By a mean of scanning electron microscopy the composition of the single crystal has been determined as Fe4.9(2)Ga1.3(1)Ge3.7(1). The crystal structures of the Fe6−xGayGe5−y (x ∼0.5, y = 1.3(1)) and all compounds in the Fe–Ge binary system have been crystallographically analyzed and structural relationship has been established.  相似文献   

8.
Ce2Ti2SiO9 – the First Titanate‐Silicate with Cerium – Preparation, Characterization, and Structure Ce2Ti2SiO9 was synthesized by chemical vapour transport in a temperature gradient (1050 °C → 900 °C) using Ce2Ti2O7 as precursor and ammoniumchloride as transport agent. SiO2 was provided from the wall of the used silica tubes. The chemical composition of the crystals was determined by EDX and EELS analysis. The structure of Ce2Ti2SiO9 was determined and refined to R1 = 0.025, wR2 = 0.067, respectively. The monoclinic phase crystallizes in the space group C2/m (No. 12) with a = 16.907(3) Å, b = 5.7078(8) Å, c = 7.574(2) Å, β = 111.38(2)° and Z = 4. Ti is octahedral, Si is tetrahedral surrounded by oxygen. Ce(1) is coordinated by eight, Ce(2) by ten oxygen atoms. There are edge connected chains of Ti(1)–O‐octahedra parallel [010] which are connected along [001] with each other by Ti(2)–O‐octahedra‐pairs and Si–O‐tetrahedra.  相似文献   

9.
The title compounds, 2‐(4‐bromo­phenyl)‐1,2‐di­hydro­pyrimido­[1,2‐a]­benzimidazol‐4‐(3H)‐one, C16H12Br­N3O, (IVa), and 4‐(4‐methylphenyl)‐3,4‐dihydropyrimido[1,2‐a]benzimidazol‐2‐(1H)‐one, C17H15N3O, (Vb), both form R(8) centrosymmetric dimers via N—H?N hydrogen bonds. The N?N distance is 2.943 (3) Å for (IVa) and 2.8481 (16) Å for (Vb), with the corresponding N—H?N angles being 129 and 167°, respectively. However, in other respects, the supra­molecular structures of the two compounds differ. Both compounds contain different C—H?π interactions, in which the C—H?π(centroid) distances are 2.59 and 2.47 Å for (IVa) and (Vb), respectively (the latter being a short distance), with C—H?π(centroid) angles of 158 and 159°, respectively. The supramolecular structures also differ, with a short Br?O distance of 3.117 (2) Å in bromo derivative (IVa), and a C—H?O interaction with a C?O distance of 3.2561 (19) Å and a C—H?O angle of 127° in tolyl system (Vb). The di­hydro­pyrimido part of (Vb) is disordered, with a ratio of the major and minor components of 0.9:0.1. The disorder consists of two non‐interchangeable envelope conformers, each with an equatorial tolyl group and an axial methine H atom.  相似文献   

10.
In this work, the largest heterometallic supertetrahedral clusters, [Zn6Ge16]4? and [Cd6Ge16]4?, were directly self‐assembled through highly‐charged [Ge4]4? units and transition metal cations, in which 3‐center–2‐electron σ bonding in Ge2Zn or Ge2Cd triangles plays a vital role in the stabilization of the whole structure. The cluster structures have an open framework with a large central cavity of diameter 4.6 Å for Zn and 5.0 Å for Cd, respectively. Time‐dependent HRESI‐MS spectra show that the larger clusters grow from smaller components with a single [Ge4]4? and ZnMes2 units. Calculations performed at the DFT level indicate a very large HOMO–LUMO energy gap in [M6Ge16]4? (2.22 eV), suggesting high kinetic stability that may offer opportunities in materials science. These observations offer a new strategy for the assembly of heterometallic clusters with high symmetry.  相似文献   

11.
Synthesis and Crystal Structures of Zinc Rhodium Boride Zn5Rh8B4 and the Lithium Magnesium Rhodium Borides LixMg5?xRh8B4 (x = 1.1 and 0.5) and Li8Mg4Rh19B12 The title compounds were prepared by reaction of the elemental components in metal ampoules under argon atmosphere (1100 °C, 7 d). In the case of Zn5Rh8B4 (orthorhombic, space group Cmmm, a = 8.467(2) Å, b = 16.787(3) Å, c = 2.846(1) Å, Z = 2) a BN crucible enclosed in a sealed tantalum container was used. The syntheses of LixMg5?xRh8B4 (orthorhombic, space group Cmmm, Z = 2, isotypic with Zn5Rh8B4, lattice constants for x = 1.1: a = 8.511(3) Å, b = 16.588(6) Å, c = 2.885(1) Å, and for x = 0.5: a = 8.613(1) Å, b = 16.949(3) Å, c = 2.9139(2) Å) and Li8Mg4Rh19B12 (orthorhombic, space group Pbam, a = 26.210(5) Å, b = 13.612(4) Å, c = 2.8530(5) Å, Z = 2) were carried out in tantalum crucibles enclosed in steel containers using lithium as a metal flux. The crystal structures were solved from single crystal X‐ray diffraction data. In both structures Rh atoms reside at z = 0 and all non‐transition metal atoms at z = 1/2. Columns of Rh6B trigonal prisms running along the c‐axis are laterally connected to form three‐dimensional networks with channels of various cross sections containing Li‐, Mg‐, and Zn‐atoms, respectively. A very short Li‐Li distance of 2.29(7) Å is observed in Li8Mg4Rh19B12.  相似文献   

12.
The Rare Earth Metal Polyselenides Gd8Se15, Tb8Se15?x, Dy8Se15?x, Ho8Se15?x, Er8Se15?x, and Y8Se15?x – Increasing Disorder in Defective Planar Selenium Layers Single crystals of the rare earth metal polyselenides Gd8Se15, Tb8Se15?x, Dy8Se15?x, Ho8Se15?x, Er8Se15?x, and Y8Se15?x (0 < x ≤ 0.3) have been prepared by chemical transport reactions (1120 K→ 970 K, 14 days, I2 as carrier) starting from pre‐annealed powders of nominal compositions between LnSe2 and LnSe1.9. The isostructural title compounds adopt a 3 × 4 × 2 superstructure of the ZrSSi type and can be described in space group Amm2 with lattice parameters of a = 12.161(1) Å, b = 16.212(2) Å and c = 16.631(2) Å (Gd8Se15), a = 12.094(2) Å, b = 16.123(2) Å and c = 16.550(2) Å (Tb8Se15?x), a = 12.036(2) Å, b = 16.060(2) Å and c = 16.475(2) Å (Dy8Se15?x), a = 11.993(2) Å, b = 15.999(2) Å and c = 16.471(2) Å (Ho8Se15?x), a = 11.908(2) Å, b = 15.921(2) Å and c = 16.428(2) Å (Er8Se15?x), and a = 12.045(2) Å, b = 16.072(3) Å and c = 16.626(3) Å (Y8Se15?x), respectively. The structure consists of puckered [LnSe] double slabs and planar Se layers alternating along [001]. The planar Se layers contain a disordered arrangement of dimers, Se2? and vacancies. All compounds are semiconducting and contain trivalent rare earth metals (Ln3+).  相似文献   

13.
Structures of cyclic 2‐(3‐oxo‐3‐phenylpropyl)‐substituted 1,3‐diketones 4a – c were determined by 17O‐NMR spectroscopy and X‐ray crystallography. In CDCl3 solution, compounds 4a – c form an eight‐membered‐ring with intramolecular H‐bonding between the enolic OH and the carbonyl O(11)‐atom of the phenylpropyl group, as demonstrated by increased shielding of specifically labeled 4a – c in the 17O‐NMR spectra (Δδ(17O(11))=36 ppm). In solid state, intermolecular H‐bonding was observed instead of intramolecular H‐bonding, as evidenced by the X‐ray crystal‐structure analysis of compound 4b . Crystals of compound 4b at 293 K are monoclinic with a=11.7927 (12) Å, b=13.6230 (14) Å, c=9.8900 (10) Å, β=107.192 (2)°, and the space group is P21/c with Z=4 (refinement to R=0.0557 on 2154 independent reflections).  相似文献   

14.
The synthesis of two formyl 2‐tetrazenes, namely, (E)‐1‐formyl‐1,4,4‐trimethyl‐2‐tetrazene ( 2 ) and (E)‐1,4‐diformyl‐1,4‐dimethyl‐2‐tetrazene ( 3 ), by oxidation of (E)‐1,1,4,4‐tetramethyl‐2‐tetrazene ( 1 ) using potassium permanganate in acetone solution is presented. Compound 3 was also synthesized in an improved yield from the oxidation of 1‐formyl‐1‐methylhydrazine ( 4a ) using potassium permanganate in acetone. Both compounds 2 and 3 were characterized by analytical (elemental analysis, GC‐MS) and spectroscopic methods (1H, 13C, and 15N NMR spectroscopy, and IR and Raman spectroscopy). In addition, the solid‐state structures of the compounds were confirmed by low‐temperature X‐ray analysis. (Compound 2 : triclinic; space group P‐1; a=5.997(1) Å, b=8.714(1) Å, c=13.830(2) Å; α=107.35(1)°, β=90.53(1)°, γ=103.33(1)°; VUC=668.9(2) Å3; Z=4; ρcalc=1.292 cm?3. Compound 3 : monoclinic; space group P21/c; a=5.840(2) Å, b=7.414(3) Å, c=8.061(2) Å; β=100.75(3)°; VUC=342(2) Å3; Z=2; ρcalc=1.396 g cm?3.) The vibrational frequencies of compounds 2 and 3 were calculated using the B3LYP method with a 6‐311+G(d,p) basis set. We also computed the natural bond orbital (NBO) charges using the rMP2/aug‐cc‐pVDZ method and the heats of formation were determined on the basis of their electronic energies. Furthermore, the thermal stabilities of these compounds, as well as their sensitivity towards classical stimuli, were also assessed by differential scanning calorimetry and standard BAM tests, respectively. Lastly, the attempted synthesis of (E)‐1,2,3,4‐tetraformyl‐2‐tetrazene ( 6 ) is also discussed.  相似文献   

15.
The new ternary phase Eu2–xMg2–yGe3 (x = 0.1, y = 0.5) was obtained by solid‐state synthesis and the structure determined by means of Single Crystal X‐ray Diffraction. The compound crystallizes with the orthorhombic space group Cmcm (no. 63) having structural features of the low‐temperature modification of LaSi. The crystal structure contains two different types of germanium anions: isolated Ge4– and $\rm^{2}_{\infty}$ [Ge2–xy] chains. The cation substructure is partially disordered and is best represented assuming a split position. The chemical bonding is well represented by the Zintl‐Klemm concept. Resistivity measurements reveal that the compound is metallic. DFT band structure calculations were carried out on the ideal stoichiometric compound Eu2Mg2Ge3, showing that this model (x = 0; y = 0) would be also metallic as a consequence of the ecliptic stacking of anions. Susceptibility and specific heat measurements evidence the presence of weak, and probably frustrated, antiferromagnetic interactions between disordered europium atoms.  相似文献   

16.
The new clathrate Ba8–xEuxGe433 (x = 0.6) was synthesized at a pressure of 1 GPa and temperatures of up to 1220 K by means of a multi‐anvil device (Walker module) and a hydraulic 1000 ton press. X‐ray powder diffraction data indicate that the crystal structure of Ba8–xEuxGe433 (x = 0.6, space group , a = 21.2588(3) Å) corresponds to that of Ba8Ge433. Measurements of the magnetic susceptibility of Ba8–xEuxGe433 reveal Curie‐paramagnetic behaviour and prove that the electronic state of europium corresponds to 4f7, i.e., Eu2+. Electrical resistivity shows a metal‐like temperature dependence and ρ(300) ≈ 2mΩ cm for x = 0.6. Heat capacity measurements reveal an upturn of cp/T(T) below 7 K that is attributed to magnetic interaction of the europium ions.  相似文献   

17.
The new compounds Pr8(C2)4Cl5 (1), Pr14(C2)7Cl9 (2), Pr22(C2)11Cl14 (3), Ce2(C2)Cl (4), La2(C2)Br (5), Ce2(C2)Br (6), Pr2(C2)Br (7), Ce18(C2)9Cl11 (8), and Ce26(C2)13Cl16 (9) were prepared by heating mixtures of LnX3, Ln and carbon or in an alternatively way LnX3, and “Ln2C3–x” in appropriate amounts for several days between 750 and 1200 °C. The crystal structures were investigated by X‐ray powder analysis (5–7) and/or single crystal diffraction (1–4, 8, 9). Pr8(C2)4Cl5 crystallizes in space group P21/c with the lattice parameters a = 7.6169(12), b = 16.689(2), c = 6.7688(2) Å, β = 103.94(1) °, Pr14(C2)7Cl9 in Pc with a = 7.6134(15), b = 29.432(6), c = 6.7705(14) Å, β = 104.00(3) °, Pr22(C2)11Cl14 in P21/c with a = 7.612(2), b = 46.127(9), c = 6.761(1) Å, β = 103.92(3) °, Ce2(C2)2Cl in C2/c with a = 14.573(3), b = 4.129(1), c = 6.696(1) Å, β = 101.37(3) °, La2(C2)2Br in C2/c with a = 15.313(5), b = 4.193(2), c = 6.842(2) Å, β = 100.53(3) °, Ce2(C2)2Br in C2/c with a = 15.120(3), b = 4.179(1), c = 6.743(2) Å, β = 101.09(3) °, Pr2(C2)2Br in C2/c with a = 15.054(5), b = 4.139(1), c = 6.713(3) Å, β = 101.08(3) °, Ce18(C2)9Cl11 in P$\bar{1}$ with a = 6.7705(14), b = 7.6573(15), c = 18.980(4) Å,α = 88.90(3) °, β = 80.32(3) °, γ = 76.09(3) °, and Ce26(C2)13Cl16 in P21/c with a = 7.6644(15), b = 54.249(11), c = 6.7956(14) Å, β = 103.98(3) ° The crystal structures are composed of Ln octahedra centered by C2 dumbbells. Such Ln6(C2)‐octahedra are condensed into chains which are joined into undulated sheets. In compounds 1–4 three and four up and down inclined ribbons alternate (4+4, 4+33+4–, 4+43+44+3), in compounds 8 and 9 four and five (4+5, 5+44+54+4), and in compounds 4–7 one, one ribbons (1+1) are present. The Ln‐(C2)‐Ln layers are separated by monolayers of X atoms.  相似文献   

18.
A series of five l ‐di‐p‐toluoyl‐tartaric acid (l ‐DTTA) lanthanide coordination polymers, namely {[Ln4K4 L6(H2O)x]?yH2O}n, [Ln=Dy ( 1 ), x=24, y=12; Ln=Ho ( 2 ), x=23, y=12; Ln=Er ( 3 ), x=24, y=12; Ln=Yb ( 4 ), x=24, y=11; Ln=Lu ( 5 ), x=24, y=12] have been isolated by simple reactions of H2L (H2L= L ‐DTTA) with LnCl3?6 H2O at ambient temperature. X‐ray crystallographic analysis reveals that complexes 1 – 5 feature two‐dimensional (2D) network structures in which the Ln3+ ions are bridged by carboxylate groups of ligands in two unique coordinated modes. Luminescent spectra demonstrate that complex 1 realizes single‐component white‐light emission, while complexes 2 – 4 exhibit a characteristic near‐infrared (NIR) luminescence in the solid state at room temperature.  相似文献   

19.
Tb16Br23B4: Tetrameric Terbium Clusters with Endohedral Boron Atoms The new cluster compound Tb16Br23B4 was prepared from a stoichiometric mixture of Tb‐metal, TbBr3 and B‐powder under Ar‐atmosphere in sealed Ta ampoules at 920–950 °C. It crystallizes monoclinic in the space group C2/m with a = 17.523(4) Å, b = 12.008(2) Å, c = 11.901(2) Å und β = 103.95(3)°. In the crystal structure B‐centered Tb6 octahedra are connected via common edges to form tetrameric units. The Br atoms connect the Tb16B4‐clusters 3‐dimensionally coordinating the unoccupied edges and corners of the octahedra. Tb16Br23B4 is a semiconductor with an electrical band gap of Eg = 0.4 eV. The magnetic susceptibility follows a Curie‐Weiss law corresponding to an effective magnetic moment μeff = 9.55 μB at high temperatures with an antiferromagnetic ordering below 20 K.  相似文献   

20.
The reaction of NiCl2 and 3‐hydrazine‐4‐amino‐1,2,4‐triazole (Hatr) in the mixed solvent of EtOH and H2O yielded a dimer compound ([Ni2(Hatr)2(H2O)2(EtOH)2Cl2]Cl2·EtOH) with water and EtOH molecules coordinated to nickle ions. It crystallized in trigonal space group R‐3, a=b=29.67(1) Å, c=8.95(7) Å, β=120(1)°, as determined by single‐crystal X‐ray diffraction. Then, they were fully characterized by the IR spectroscopy, differential scanning calorimetry (DSC), thermogravimetry (TG), and elemental analysis.  相似文献   

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