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1.
A Partial Statistically Incorporation of Ca2+ into the Ba6Nd2Al4O15-Type: Ba5CaLa2Fe4O15 Using high temperature reactions we succeeded in incorporating Ca2+ into the Ba6Nd2Al4O15 type. Single crystal X-ray methods reveal a partly ordered alkaline earth distribution. Ba2+ and Ca2+ occupy face connected MO6-octahedra as well as a further point position together with La3+ ions (space group C−P63mc; a = 11.770; c = 7.039 Å; Z = 2).  相似文献   

2.
On Ruthenium perovskites of type Ba2BRuO6 and Ba3BRu2O9 with B = Indium, Rhodium The black perovskites Ba2InRu5+O6 and Ba3InRu2O9 (mean oxydation state of ruthenium: +4.5) adopt the hexagonal BaTiO3 structure and form a continuous series of mixed crystals. According to the intensity calculations and analysis of the vibrational spectroscopic data an ordered distribution between indium and ruthenium is present: 1:1 order in Ba2InRuO6 (space group P3 m1 ? D; R′ = 5.3%); 1:2 order in Ba3InRu2O9 (space group P63/mmc ? D; R′ = 4.6%). The corresponding black Rh compounds, Ba2RhRuO6 and Ba3RhRu2O9, crystallize in the rhombohedral 9 L type of BaRuO3.  相似文献   

3.
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   

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 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   

6.
The Structures of the Hexagonal Elpasolite-Type Compounds Ba3NiSb2O9 and Ba3CuSb2O9 The results of an X-ray single crystal study of the hexagonal elpasolite Ba(NiSb2)(6)O9 are given. (Space group: C; a = b = 5.837 Å, c = 14.392 Å; Z = 2). The structure can be described by close-packed BaO3 layers alternating in the sequence c c h c c h … (hex. BaTiO3 type). Groups of two octahedra with common faces are connected by SbO6 octahedra via common corners. They are occupied alternately by Ni and Sb. The final reliability index was R = 3.0%. The Cu2+-compound is of the same structural type. The ligand field and EPR spectra are discussed in comparison with related Ni2+ and Cu2+ compounds.  相似文献   

7.
On Hexagonal Perovskites with Cationic Vacancies. XXVI. Ba12Ba2 2/3M 1/32O333 (MV = Nb, Ta) – the First Stacking Polytypes of a Rhombohedral 36 L-Type In the systems BaO? MO5(MV = Nb, Ta) for a Ba:MV ratio of 2:1 polymorphism is observed. Here the low temperature modifications are described. They crystallize in a rhombohedral 36 L structure with three formula units Ba12Ba2 2/3M 1/32O333 for the trigonal setting (MV = Nb: a = 5.922 Å; c = 93.25 Å; Ta: a = 5,922 Å; s = 93.4 Å).  相似文献   

8.
On Hexagonal Perovskites with Cationic Vacancies. XXXI. Systems BaO? Re2O7? M O5 with MV = Nb, Ta In the systems BaO? Re2O7? MO5 three quaternary oxides are formed, which belong to the perovskite stacking polytypes with cationic vacancies: Ba8Re7/2M□3O24 (MV = Nb, Ta; rhombohedral 24 L type; sequence (hhhhchhc)3; space group R3 m), Ba4Re9/8Ta13/85/4O12 (rhombohedral 12 L type; sequence (hhcc)3; space group R3 m) and the phases Ba5BaRe3/2?xM □O15?xx (MV = Nb, Ta; variants of a hexagonal 5 L type).  相似文献   

9.
Determination of Structures of Ordered Perovskites of the Ba2B MVIO6 Type Intensity calculations on powder patterns of Ba2Y□0.33MVIO6 with MVI = U, W, Te und Ba2Gd0.670.33UO6 lead for the space group Fm3m/O with 8 Ba in 8c, 8/3 BIII and 4/3 □ in 4b, 4 MVI in 4a and 24 O in 24e to R values between 4.3 and 7.6%. Two further models are discussed.  相似文献   

10.
On Hexagonal Perovskites with Cationic Vacancies. I. Compounds of the Type Ba2B □2/3ReVIIO6 Compounds of Type Ba2B□2/3ReVIIO6 are formed with BIII = Sm? Gd Ho? Lu, Y, Sc, In (yellow); Tb (black-brown); Dy (yellow-orange). They crystallize with BIII = Sm? Lu, Y and Sc in a rhombohedral layer structure of 12 L-type (space group R3 m; sequence: cchhcchhcchh) with 6 formula units in the unit cell.  相似文献   

11.
On Hexagonal Perovskites with Cationic Vacancies. XVI. Rhombohedral 12 L-Stacking Polytypes Ba3AIIIM □O12 with MV = Nb, Ta The white quaternary oxides Ba3LaM□O12 with MV = Nb, Ta belong to the group of hexagonal perovskites with cationic vacancies. They crystallize in a rhombohedral 12 L-structure (sequence (hhcc)3; space group R3 m) with a = 5.751 Å; c = 28.11 Å (MV = Nb); a = 5.746 Å; c = 28.20 Å (Ta) and Z = 3. Signs for the formation of isotypic compounds with AIII = Pr, Nd could be obtained as well.  相似文献   

12.
Synthesis and Crystal Structure of Sr2Zn(OH)6 and Ba2Zn(OH)6 Crystallization from supersaturated sodium hydroxozincate solutions by adding solutions of alkali earth metal hydroxides yields crystals of Sr2Zn(OH)6 and Ba2Zn(OH)6. The X-ray structure determination on these crystals was successful including all hydrogen positions: Sr2Zn(OH)6: P21/n, Z = 2, a = 5.794(1) Å, b = 6.160(1) Å, c = 8.141(1) Å, b = 91.23(1)°, N(F ³° 2σ F) = 1127, N(Var.) = 53, R1/wR2 = 0.047/0.081Ba2Zn(OH)6: P21/n, Z = 2, a = 6.043(1) Å, b = 6.336(1) Å, c = 8.451(2) Å, b = 91.23(2)°, N(F ° 2σ F) = 1669, N(Var.) = 54, R1/wR2 = 0.029/0.067. Sr2Zn(OH)6 and Ba2Zn(OH)6 crystallize isotypic in a distorted Li2O structure type. Sr2+ resp. Ba2+ form a cubic primitive arrangement. Distorted octahedra of OH around Zn2+ fill therein alternating cubic gaps in an ordered way.  相似文献   

13.
On the Atomic Distribution in Ba2SrIn2O6 with a Contribution to the Existence of the Calciumferrite-Type of Oxoindates (I) Ba2SrIn2O6 and (II) Sr0.93Ba0.07In2O4 were prepared and investigated by single crystal X-ray technique. I crystallizes with tetragonal symmetry, space group D – I4/mmm, a = 4.168; c = 21.290 Å; Z = 2; II belongs to the orthorhombic space group D – Pnma, a = 9.858; b = 3.273; c = 11.520 Å; Z = 4. I shows in respect to the formerly investigated compound BaSr2In2O6 an unexpected statistically distribution of Ba2+ and Sr2+ with the La2SrCu2O6 type. II marks the range of existence of the calciumferrite type within the alkaline earth oxoindates in direction of large radii of M2+ ions.  相似文献   

14.
On a New Oxometallate of Manganese (II): Ba5Mn4Nd8O21 Single crystals of Ba5Mn4Nd8O21 were prepared for the first time by CO2-Laser technique using H2-atmosphere. It was investigated by a single crystal X-ray diffractometer study. Ba5Mn4Nd8O21 crystallizes with tetragonal symmetry space group: C? I4/m; a = 14.2104 Å; c = 5.8581 Å; Z = 2. Mn2+ is found in square pyramids of oxygen.  相似文献   

15.
On Hexagonal Perovskites with Cationic Vacancies. XXX. 5 L Stacking Polytypes in the Systems BaO — Re2O7? Sb2O5 and BaO? WO3? Sb2O5 In the systems BaO? Re2O7? Sb2O5 and BaO? WO3? Sb2O5 phases of composition Ba5BaRe Sb□O15?xx (x = 0 up to x ? 3/4) and Ba5BaWSb□O15?x/2x/2 (x ? 3/2 up to x ? 2) are existent, which have an orthorhombic distorted 5 L structure. The pure Sb compound has to be formulated as Ba3BaSb2O9 and crystallize in an orthorhombic variant of the hexagonal BaTiO3 type.  相似文献   

16.
Ba2BiV3O11 containing Bismuth within closed Coordination A new barium bismuth oxovanadate, Ba2BiV3O11, was prepared and investigated by X-Ray single crystal technique. It crystallizes with monoclinic symmetry space group C—P21/a, lattice constants a = 24.6473; b = 7.7347; c = 5.6375 Å, β = 103.16°; Z = 4. Octahedra arround Bi3+, tetrahedra and double tetrahedra arround V5+ form a tunnel structure. The tunnel positions are occupied by Ba(2).  相似文献   

17.
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   

18.
On the Oxoargentato(I)-aurat(III): Ba4AgAuO6 The hitherto unknown compound Ba4AgAuO6 was prepared by oxidizing Ba/Au/Ag alloy with BaO2/Ba(OH)2 mixture in closed Ag tubes. X-ray single crystal investigation led to orthorhombic symmetry space group D-Cmcm; a = 13.275; b = 5.782; c = 11.396 Å; Z = 4. Ba4AgAuO6 shows distorted pentagonal bipyramidal polyhedra around Ba2+ and square planar AuO4 polygones. Ag+ shows an unusual 2 + 2 coordination by O2?.  相似文献   

19.
A New Crystal Structure of ABLn2O5 Compounds. About BaNiNd2O5 The compound BaNiNd2O5 was prepared by solid state reaction. Single crystal examination show a new structure type (a = 3.829(2), b = 5.932(3), c = 11.649(3) Å space group D–Immm, Z = 2) with Ni2+ in octahedral coordination. The surrounding of Ba2+ and Nd3+ conforms to BaPtNd2O5 with significant differences of the polyhedra connection.  相似文献   

20.
About Ba6La2Co4O15 Ba6La2Co4O15 were prepared and investigated by X-ray single crystal work. It crystallizes with hexagonal symmetry, space group C–P63mc; a = 11.8082; c = 7.0019 Å; Z = 2. Ba2+ show face connected BaO6-octahedra and larger polyhedra of C.N. = 10 and 12. Co3+ is surrounded by four and six (tetrahedra, octahedra) oxygen. The Ba2+ and La3+ ions occupy one point position statistically.  相似文献   

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