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1.
On Ordered Perovskites with Cationic Vacancies. XI. Compounds of Type A B B □1/4WVIO6 ? A BIIB □W O24 with AII, BII = Ba, Sr Depending on the ionic radii of the two and three valent cations in the perovskites of type ABB □1/4WVIO6 ?; ABIIB □WO24 order disorder phenomena are present. The results of the x-ray and vibrational spectroscopic investigations as well as the diffuse reflectance spectra and the visible photoluminescence are reported.  相似文献   

2.
Dibromomethylsulfoniumsalts — Preparation and Crystal Structure The salts CH3SBrA? (A? = SbCl, AsF) were prepared by various routes and characterized by their Ramanspectra. CH3SBrAsF crystallized in the monoclinic space group P21/c with a = 770,5(4) pm, b = 942,4(12) pm, c = 1329,3(14) pm, β = 100,28(6)°, Z = 4. Distances and bond angles in the cation are as expected.  相似文献   

3.
On the Stoichiometry of the Allotropic Variation γ-Bi2O3 The study of the solid solutions Bi12[BBi□1/5]O20 (B+V = As, V) with 0 ? x ? 0,80 leads for x = 0,77 to a phase whose cubic centered symmetry and parameter (10.255 Å) correspond to those previously announced for γ-Bi2O3. The présence of impurities seems required to obtain such a phase whose theoretical stoichiometry should be Bi12[Bi□1/5]O20 i. e. Bi2O3,125.  相似文献   

4.
On Perovskites Ba2B B TeVIO6 Compounds of composition Ba2BBTeVIO6 with BI = Li, Na; BIII = La, Pr, Nd, Sm, Eu, Gd, Tb, Ho, Yb, Y, In, Sc crystallize in a cubic 1:1 ordered perovskite structure. The vibrational spectroscopic investigations show, that more species of TeO6 octahedra are present in the lattice.  相似文献   

5.
On Ordered Perovskites with Cationic Vacancies. X. Compounds of Type A B B □1/4MVIO6 ? A BIIB □M O24 with AII, BII = Ba, Sr, Ca and MVI = U, W Perovskites of type Ba8BIIB2III□UO24 show polymorphic phase transformations of order disorder type. An 1:1 ordered orthorhombic HT form is transformed into a higher ordered LT modification with a fourfold cell content (four formula units Ba8BIIB□U4O24), compared to cubic 1:1 ordered perovskites A2BMO6. In the series Ba8BaB□W4O24 and Sr8SrB□W4O24 different ordering phenomena are observed. In comparison with 1:1 ordered cubic perovskites A2BMO6, the cell contains eight formula units ABIIB□W4O24. The higher ordered cells with UVI and WVI are face centered, which has its origin in an ordering of cationic vacancies.  相似文献   

6.
Vibration spectra and force constants of the series O2PF — S2PF — S2P(CH3). The vibrational spectra of OSPF, S2PF, S2PF(CH3) and S2P(CN) are reported and discussed with O2PF and S2P(CH3). On the basis of a simplified valence-force-field the force constants are calculated and the bonding relations are discussed. In the ions, f PF is lower than in corresponding molecules. The ionic charge is distributed over nearly all atoms of the ions.  相似文献   

7.
On Hexagonal Perovskites with Cationic Vacancies. XXIV. Rhombohedral 9 L Stacking Polytypes in the Systems Ba3W M □O9?x/2x?2 with MV = Nb, Ta In the system Ba3WNb□O9?x/2x/2 stacking polytypes of rhombohedral 9 L type (sequence (hhc)3; space group R3 m) can be prepared with ~1/3 ? × ? 2. For x = 2(Ba3Nb2□O8□) two modifications are formed. In the corresponding Ta system the phase with is reduced to a smaller region with x ? 1/3.  相似文献   

8.
19F NMR Spectroscopic Evidence and Calculation of the Statistical Formation of Mixed Cluster Anions [(Mo6Br Cl )F ]2?, n = 0 – 8 The complete system of the innersphere mixed clusters (Mo6BrCl)4+ is formed by exchange of innersphere bound Cli against outersphere bound Bra on tempering the solid [(Mo6Cl)Br] at 500°C for 16 h. After conversion with conc. HCl into (H3O)2[(Mo6BrCl)Cl] and precipitation of the outer Cla with AgBF4 in ethanol, treatment with tetrabutylammonium(TBA)fluoride yields (TBA)2 [(Mo6BrCl)F], a mixture of 22 different species. According to the sets of chemical equivalent fluorine atoms in total 55 19F nmr signals are expected, which are really observed in the high resolution 1D-19F-nmr spectrum. Using increments of chemical shifts, peak intensities and multiplet structures as well as the 2D-19F/19F-COSY spectrum the complete and unambiguous assignment of all resonances is achieved. From the measured integral intensities the distribution of the different compounds is determined, revealing statistical formation of the geometrical isomers.  相似文献   

9.
The blue mixed-crystal title compound Na15[MoMoO462H14 (H2O)70]0.5[MoMoO457H14 · (H2O)68]0.5 · ca. 400 H2O ≡ Na15[ 1 a ]0.5[ 1 b ]0.5 · ca. 400 H2O 1 , which crystallizes in the triclinic space group P 1 (a = 30.785(2), b = 32.958(2), c = 47.318(3) Å, α = 90.53(1), β = 89.86(1), γ = 96.85(1)°, V = 47665(6) Å3, Z = 2, Dcalc = 2.149 g cm–3), precipitates within one day when an acidic (pH ≈ 1) aqueous solution of sodium molybdate (because of the extremely high solubility of the reaction product used in relatively high concentration) is reduced by sodium dithionite. 1 contains hitherto unknown pure molybdenum-oxide based, nanosized, ring-shaped, crystallographically independent cluster anions of the type {Mo154} 1 a and {Mo152} 1 b , the lacunary-type analogue of 1 a . Using the same reducing agent but in the presence of a reagent with a high affinity to the specific {Mo2}-type building unit (also a leaving group) of 1 a , such as formic acid, the compound Na22[MoMoO442H14(H2O)58] · ca. 250 H2O 2 (space group P 1, a = 24.724(1), b = 35.726(2), c = 44.608(3) Å, α = 93.25(1), β = 93.51(1), γ = 106.72(1)°, V = 37552(4) Å3, Z = 2, Dcalc = 2.401 g cm–3) is obtained in which the giant rings, having four missing {Mo2} units compared to 1 a , are linked to chains. Until now, similar chain-type compounds could only be obtained using a non-well-defined synthetic method.  相似文献   

10.
On the Formation of Monoselenane and Monotellurane Disulphane-diphosphonate by the Reaction of SPO with Seleno and Telluropolythionates In the reaction of seleno- and telluropolythionates with SPO, SeS2P2O and TeS2P2O are formed and are described for the first time. Polysulfphane-diphosphonates, -disulphonates and -phosphonsulphonates occur as side and consecutive products. By evaluation of radiochemical double labelling with the nuclide pairs 35S? 32P and 35S? 75Se, it is possible to identify the products formed and obtain information about the reaction mechanism.  相似文献   

11.
LaCl(BO2)2 and Er2Cl2[B2O5]: Two Chloride Oxoborates of Trivalent Lanthanides Er2Cl2[B2O5] is obtained as single crystals by the reaction of ErCl3, Er2O3 and B2O3 with an excess of ErCl3 as flux in evacuated silica tubes after two weeks at 850 °C. The compound crystallizes as long, pale pink needles and appears to be air‐ and water‐resistant. Single‐crystalline LaCl(BO2)2 emerges from the reaction of La2O3, LaCl3, and B2O3 with an excess of B2O3 as flux in evacuated silica tubes after four weeks at 900 °C. LaCl(BO2)2 crystallizes as thin, colourless, air‐ and water‐resistant needles which tend to severe twinning due to their fibrous habit. The crystal structure of Er2Cl2[B2O5] (orthorhombic, Pbam; a = 1489.65(9), b = 1004.80(6), c = 524.86(3) pm; Z = 4) contains two crystallographically different erbium cations. (Er1)3+ resides in pentagonal‐bipyramidal coordination of seven anions while (Er2)3+ is surrounded by only six anions with the shape of an octahedron. The planar oxodiborate units [B2O5]4— consisting of two vertex‐shared [BO3]3— triangles are isolated according to {([BOO]2)4—}. LaCl(BO2)2 crystallizes isostructurally with PrCl(BO2)2 in the triclinic space group P1¯ (a = 423.52(4), b = 662.16(7), c = 819.33(8) pm; α = 82.081(8), β = 89.238(9), γ = 72.109(7)°; Z = 2). The characteristic unit consists of endless chains built up by corner‐linked [BO3]3— triangles. These quasi‐planar zigzag chains of the composition {[(B1)OO(B2)OO]2—} (≡ {[BO2]} run parallel [100]. The La3+ cations exhibit coordination numbers of ten and are coordinated by three Cl and seven O2— anions.  相似文献   

12.
Magnetic interactions in some oxyfluoroferrites of spinel structure with the formula ZnxMe2?xO4?xFx (M = Fe, Co, Ni) Whereas the ferromagnetic spin arrangement of the B-cations is not modified by the Zn2+?Fe3+ substitution in the ZnFe[Fe2+Fe3+]O4?xFx (0 ≤ x ≤ 0,50) spinel, this same substitution leads to a spin canting in the ZnFe[Co2+Fe3+]O4?xFx and ZnFe[Ni2+Fe3+]O4?xFx (0 ≤ x ≤ 0,80) simples. The difference in the magnetic behaviors with regard to the AB and BB interactions can be explained on the basis of the magnetic exchange theory.  相似文献   

13.
Photoluminescence of Trivalent Rare Earths in Perovskite Stacking Polytypes Ba2La2?x RE MgW2□O12, Ba6Y2?x RE W3□O18, and Sr8SrGd2?xRE W4□O24 Rhombohedral 12 L stacking polytypes Ba2La2?xREMgW2□O12 show with RE3+ = Pr, Sm, Eu, Tb, Dy, Ho, Er, Tm; the 18 L stacking polytypes Ba6Y2?xREW3□O18 and the polymorphic perovskites Sr8SrGd2?xREW4□O24 with RE3+ = Sm, Eu, Dy, Ho, Er visible photoluminescence. The concentration dependence and the influence of the coordination number of the rare earth are reported.  相似文献   

14.
Preparation and Spectroscopic Characterization of the Cluster Anion [(Mo6Cl )(CF3COO) ]2? On heating of [(Mo6Cl)Cl]2? in dichloromethane with trifluoroacetic acid the new stable cluster anion [(Mo6Cl)(CF3COO)]2? is formed by elimination of HCl. The (Mo6Cl) unit remains unattacked. The 19F nmr spectrum exhibits a downfield shifted singulett as compared to free CF3COO? indicating the equivalence of all trifluoroacetate ligands, which unidentate coordination is deduced from characteristic i. r. frequencies of the carboxyl groups. The most intense i.r. band at 501 cm?1 is assigned to the antisymmetric Mo? Oa vibration, the most intense Raman line at 319 cm?1 to the breathing mode of the Cl cube.  相似文献   

15.
On Perovskites A B B WVIO6 Compounds of type ABBWVIO6 can be obtained with AII ? Ba; BI ? Li, Na and BIII ? La, Nd, Sm, Gd, Y, In, Sc just as with AII ? Sr, BI ? Li and BIII ? La, Nd, Sm, Gd, Y, In (all cubic ordered perovskites). For the cubic perovskites Sr2Na0,5La0,5WO6 and Sr2Na0,5Nd0,5WO6 additional superlattice reflections are observed (a ∽ 16.4 Å). The compounds Sr2Na0,5BWO6 crystallize with BIII ? Sm, Gd in a monoclinic and with BIII ? Y, In in a rhombic distorted perovskite lattice. For the perovskites with A = Sr — dependent on ionic radii of the B ions — two different lattice types are present.  相似文献   

16.
Tetraammine Lithium Cations Stabilizing Phenylsubstituted Zintl-Anions: The Compound [Li(NH3)4]2[Sn2Ph4] Ruby-red, brittle single crystals of [Li(NH3)4]2[Sn2Ph4] were synthesized by the reaction of diphenyltin dichloride and metallic lithium in liquid ammonia at ?35°C. The structure was determined from X-ray singlecrystal diffractometer data: Space group, P1 , Z = 1, a = 9.462(2) Å, b = 9.727(2) Å, c = 11.232(2) Å, α = 66.22(3)°, β = 85.78(3)°, γ = 61.83(3)°, R1 (F ? 4σF) = 5.13%, wR2 (F02 ? 4σF) = 10.5%, N(F ? 4σF) = 779, N(Var.) = 163. The compound contains to Sb2Ph4 isosteric centres [Sn2Ph4]2? as anions which are connected to rods by lithium cations in distorted tetrahedral coordination by ammonia. These rods are arranged parallel to one another in the b,c-plane, but stacked along [100].  相似文献   

17.
The crystal structure of the title compound has been determined from three dimensional x-ray data obtained by the multiple film method. The space group is P2l/n and the cell dimensions are: a = 14.90, b = 16.84, c = 8.38 Å; β = 93.5° Z = 4. The structure is formed by discrete Co (en) and Fe(CN) ions, both of which have an octahedral configuration. The Fe(CN) ions are approximately octahedrally surrounded by the Co (en) ions while arrangement of Fe (CN) ions around the Co(en) ions completely differs from an octahedron. The mean Fe? C and Co? C dustances are 1.91 and 2.01 Å, respectively. The water molecules do not play an important role in the structure and all distances between oxygen and other atoms indicate the presence of very weak hydrogen bonds. The salts M (en)3 Q(CN)6 · H2O, where M = Co and Cr and Q = Cr, Mn, Fe and Co, are all isomorphous.  相似文献   

18.
Cs5[Na{W4N10}] was prepared from a mixture of NaNH2, CsNH2 and tungsten powder (molar ration 1 : 10 : 4) at 700°C in autoclaves. After the reaction is finished the nitride is embedded in an alkali metal matrix. Dark red crystals were isolated by washing out the alkali metal with liquid ammonia at room temperature. The structure of Cs5[Na{W4N10}] was solved by X-ray single crystal data: I41 (No. 80), Z = 4, a = 13.926(3) Å, c = 8.723(3) Å, Z(F) ≥ 3σ(F) = 1535, Z(Variables) = 63, R/Rw = 0.040/0.052. The compound is highly sensitive against moisture giving oxotungstates and ammonia. It contains a framework of tetrahedra [WNN3/21.5?]. Sodium shares four terminal nitrogen ligands. Including sodium a distorted, β-cristobalite type arrangement [Na{W4N10}5?] results. It contains caesium in all interstices formed by twelve nitrogen ligands in so-called Friauf polyhedra.  相似文献   

19.
The Structures of two Hydrates of Sodium Phenoxide: C6H5ONa · H2O and C6H5ONa · 3 H2O In the monohydrate of sodium phenoxide sodium is coordinated by 4 oxygen atoms having an average distance Na? O of about 2.631 Å being arranged in form of a distorted tetrahedron. The oxygen atoms of water and phenoxid serve as bridging ligands. Hence, the structure can be considered as a network with a general formula [Na[4]O]. Moreover, the oxygen atoms are linked via hydrogen bonding. In the trihydrate of sodium phenoxide sodium is surrounded with 5 oxygen atoms with an average distance of 2.39 Å forming a tetragonal pyramide. The oxygen of the phenoxide, however, does not participate in the coordination of the sodium ion. The coordination polyhedrons are connected by sharing edges and verteces. The resulting layer can be described by the general formula [Na[5]O2[2]O[2]O[1]]. Via hydrogen bonding the phenoxide ions are attached to this layer.  相似文献   

20.
Synthesis, Crystal Structures, and Vibrational Spectra of [(Mo6X)Y]2–; Xi = Cl, Br; Ya = NO3, NO2 By treatment of [(Mo6X)Y]2–; Xi = Ya = Cl, Br with AgNO3 or AgNO2 by strictly exclusion of oxygene in acetone the hexanitrato and hexanitrito cluster anions [(Mo6X)Y]2–, Ya = NO2, NO3 are formed. X-ray structure determinations of (Ph4As)2[(Mo6Cl)(NO3)] · 2 Me2CO ( 1 ) (monoclinic, space group P21/n, a = 12.696(3), b = 21.526(1), c = 14.275(5) Å, β = 115.02(2)°, Z = 2), (n-Bu4N)2[(Mo6Br)(NO3)] · 2 CH2Cl2 ( 2 ) (monoclinic, space group P21/n, a = 14.390(5), b = 11.216(5), c = 21.179(5)Å, β = 96.475(5)°, Z = 2) and (Ph4P)2[(Mo6Cl)(NO2)] (3) (monoclinic, space group P21/n, a = 11.823(5), b = 13.415(5), c = 19.286(5) Å, β = 105.090(5)°, Z = 2) reveal the coordination of the ligands via O atoms with (Mo–O) bond lengths of 2.11–2.13 Å, and (MoON) angles of 122–131°. The vibrational spectra of the nitrato compounds show the typical innerligand vibrations νas(NO2) (∼ 1500), νs(NO2) (∼ 1270) and ν(NO) (∼ 980 cm–1). The stretching vibrations ν(N=O) at 1460–1490 cm–1 and ν(N–O) in the range of 950–1000 cm–1 are characteristic for nitrito ligands coordinated via O atoms.  相似文献   

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