The Inverse Perovskite Nitrides (Sr3N2/3–x)Sn, (Sr3N2/3–x)Pb,and (Sr3N)Sb: Flux Crystal Growth,Crystal Structures,and Physical Properties

Black single crystals with metallic luster of (Sr₃N_2/3–x)E (E = Sn, Pb) and (Sr₃N)Sb were grown in lithium flux from strontium nitride, Sr₂N, and tin, lead, or antimony, respectively. Nitrogen deficiency in the tin and the lead compound is a result of the higher ionic charge of the tetrelide ions E^4– as compared to the antimonide ion Sb^3–. In contrast to microcrystalline samples from solid state sinter reactions obtained earlier, the flux synthesis induces nitrogen order in the nitrogen deficient tetrelides. The antimony compound crystallizes as inverse cubic perovskite [a = 517.22(5) pm, Z = 1, space group Pm3 m, no. 221] with fully occupied nitrogen site, whereas the nitrogen deficient tin and lead compounds exhibit partially ordered arrangements and a certain phase width in respect to nitrogen contents. For the tetrelides, the nitrogen order leads to a cubic 2 × 2 × 2 superstructure [E = Sn: a = 1045.64(8) pm for x = 0, a = 1047.08(7) pm for x = 0.08; and E = Pb: a = 1050.7(1) pm for x = 0, space group Fm3 m, no. 225] as derived from single‐crystal X‐ray diffraction data. The metallic tetrelides show diamagnetic behavior, which is consistent with electronic structure calculations.     

Strukturuntersuchungen an Usoviten: Ba2CaMIIV2F14 (MIII = Mn,Fe), Ba2CaMnFe2F14 und Ba2CaCuM2IIIF14 (MIII = Mn,Fe, Ga)

Structural Studies with Usovites: Ba₂CaM^IIV₂F₁₄ (M^III = Mn, Fe), Ba₂CaMnFe₂F₁₄ and Ba₂CaCuM₂^IIIF₁₄ (M^III = Mn, Fe, Ga). Single crystals of six compounds Ba₂CaM^IIM₂^IIIF₁₄ were prepared to refine their usovite type structure (space group C2/c, Z = 4) using X‐ray diffractometer data. The cell parameters of the phases studied with M^IIM₂^III= MnV₂, FeV₂, CuMn₂, MnFe₂, CuFe₂ und CuGa₂ are within the range 1374≤a/pm≤1384, 534≤b/pm≤542, 1474≤c/pm≤1510, 91, 3≤ß/°≤93, 2. The atoms Ca and M^II are incompletely ordered on the 8‐ and 6‐coordinated positions, 4e and 4b, respectively. In the case of Ba₂CaFeV₂F₁₄ and Ba₂CaCuGa₂F₁₄ there is reciprocal substitution (x≈0, 1): (Ca_1‐xM_x^II) (4e) and (M_1‐x^IICa_x) (4b). In the case of the other usovites Ca‐enriched phases Ba₂Ca(M_1‐y^IICa_y)M₂^IIIF₁₄ occured (up to y≈0, 35), exhibiting partial substitution at the octahedral position (4b) only, showing a corresponding increase in M^II‐F distances. The distortion of [M^IIF₆] and [M^IIIF₆] octahedra within the structure is considerably enhanced on replacement by Cu^II and Mn^III. The results of powder magnetic susceptibility measurements of Ba₂CaMnV₂F₁₄ and Ba₂CaFeV₂F₁₄ (T_N≈7K) are reported.     

First Observation of an Inverse Ruddlesden‐Popper Series: (A3n+1ONn−1)Bin+1 with A = Sr,Ba and n = 1, 3

Single crystals ((Ba_0.78(1)Sr_0.22)₄O)Bi₂ and ((Ba_0.62(1)Sr_0.38)₁₀N₂O)Bi₄ were successfully prepared from melt beads of Ba, Sr, and Bi in nitrogen atmosphere with oxygen impurities. The phases can be prepared in single phase from the appropriate mixtures of alkaline‐earth metal, bismuth, and bismuth oxide upon heating in pure nitrogen atmosphere. ((Ba_0.78(1)Sr_0.22)₄O)Bi₂ crystallizes in the K₂NiF₄ structure type (space group I4/mmm, No. 139, a = 522.34(5) pm, c = 1844.0(2) pm, Z = 2, R_gt(F) = 0.039) with layers of vertex‐sharing octahedra ((Ba,Sr)_4/2Ba₂O). ((Ba_0.62(1)Sr_0.38)₁₀N₂O)Bi₄ crystallizes as an isotype of Sr₄Ti₃O₁₀ (space group I4/mmm, No. 139, a = 531.3(1) pm, c = 3983.2(4) pm, Z = 2, R_gt(F) = 0.050) containing slabs of three layers of vertex‐sharing octahedra further connected via corners. These compounds are interpreted in terms of members of an inverse Ruddlesden‐Popper series with the general formula n (A₃ON_n?1)Bi · ABi or (A_3n+1ON_n?1)Bi_n+1, respectively, with n = 1, 3. Partial order of the alkaline‐earth metal ions is analyzed.     

MZrO3（M=Ba,Sr,Ca）水热合成中结构与反应活性的关系

ＭＺｒＯ_３（Ｍ＝Ｂａ，Ｓｒ，Ｃａ）水热合成中结构与反应活性的关系郑文君，庞文琴（吉林大学化学系，长春，１３００２３）关键词水热合成，ＭＺｒＯ_３（Ｍ＝Ｂａ，Ｓｒ，Ｃａ），结构，反应活性钙钛矿型复合氧化物ＭＺｒＯ３（Ｍ＝Ｂａ，Ｓｒ，Ｃａ）是重要的功能陶...     

Ce~（3＋）在钙钛矿型KMF_3（M＝Mg、Ca、Sr、Ba）基质中的发光特性

采用高温固相反应法，在Ａｒ气氛中合成了ＫＭＦ３（Ｍ＝Ｍｇ、Ｃａ、Ｓｒ、Ｂａ）基质化合物和掺杂Ｃｅ３＋的磷光体。经Ｘ射线衍射分析确定，ＫＭｇＦ３和ＫＣａＦ３属于立方晶系、钙钛矿型结构，ＫＳｒＦ３和ＫＢａＦ３具有类似的结构。测定了ＫＭＦ３∶Ｃｅ３＋的发光光谱，观察到与其结构对应的分为二种不同的光谱结构，讨论了Ｃｅ３＋的取代格位     

相对论效应对AH2化合物(A=Be,Mg, Ca,Sr, Ba)构型的影响规律探讨

讨论了相对论效应对分子构型的影响.选取第IIA族金属氢化物为介绍对象,探讨了该族金属氢化物结构变化趋势以及稳定结构中A―H键的自然键轨道(NBO)数据变化趋势,分析总结了相对论效应在轨道杂化理论中的应用并提出教学建议.     

Potential of AMnO3 (A=Ca,Sr, Ba,La) as Active Layer in Inorganic Perovskite Solar Cells

Inorganic perovskite CaMnO was proposed as a substitution for the TiO anatase in electron transport layers of solar cells containing the hybrid perovskite CH NH PbI based on increased mobility of electrons and better optical matching. Due to a suitable band gap concerning the absorption of sunlight, we investigate the potential of CaMnO and similar manganite perovskites, where Ca is replaced by either Sr, Ba or La, as an absorber layer in inorganic perovskite solar cells. In this study, we have used optical measurements on the synthesized AMnO (A=Ca, Sr, Ba, La) samples to aid density functional theory calculations (DFT) in order to accurately simulate the electronic and optical properties of AMnO compounds and gauge their potential for the role of absorber layer. Both experimental measurements and theoretical calculations show suitable band gap of 1.1-1.5 eV, depending on the compound, and absorption coefficients of the order of cm in the visible part of the spectrum.     

碱土金属钛酸盐-TiO2异质结型复合光催化活性研究

采用溶胶-凝胶法制备碱土金属钛酸盐MTiO3(M=Mg,Ca,Sr,Ba),并进一步与TiO2固相法复合制备MTiO3-TiO2异质结型复合光催化剂.以光催化降解亚甲基蓝(MB)为探针,评价了MTiO3和MTiO3-TiO2光催化剂的活性变化.结果表明,紫外光条件下碱土金属钛酸盐MTiO3的光催化活性顺序为:CaTiO3>BaTiO3>SrTiO3>MgTiO3,钙钛矿化合物的容忍因子、电负性以及催化剂的吸附性能都影响催化剂的降解效率.MTiO3与TiO2复合后形成的异质结复合光催化剂的催化活性得到显著的提高,催化剂浓度1.0g/L时,光催化反应1h后,MB(25mg/L)的降解率分别为82.6%,99.8%,93.7%,97.3%,异质结复合光催化剂活性顺序与MTiO3一致.光催化活性的提高与异质结界面形成电荷定向流动,促进光生电子、空穴的分离有关.     

Synthesis and Crystal Structures of the First Quaternary Tantalum Thiogermanates,ATaGeS5 (A = K,Rb, Cs)

The new quaternary thiogermanates, ATaGeS₅ (A = K, Rb, Cs) were prepared with the use of halide fluxes and the crystal structures of the compounds were determined by single‐crystal X‐ray diffraction methods. The compounds are isostructural and crystallize in space group P\bar{1} of the triclinic system with two formula units in a cell of dimensions: a = 6.937(1) Å, b = 6.950(2) Å, c = 8.844(3) Å, α = 71.07(2)°, β = 78.56(2)°, γ = 75.75(2)°, V = 387.6(2) Å³ for KTaGeS₅; a = 6.996(3) Å, b = 7.033(3) Å, c = 8.985(4) Å, α = 70.33(3)°, β = 78.12(4)°, γ = 75.63(4)°, V = 399.6(3) Å³ for RbTaGeS₅; a = 7.012(4) Å, b = 7.202(3) Å, c = 9.267(5) Å, α = 68.55(3)°, β = 77.27(4)°, γ = 74.75(4)°, V = 416.2(4) Å³ for CsTaGeS₅. The structures of ATaGeS₅ (A = K, Rb, Cs) are comprised of anionic infinite two‐dimensional {}_\infty^2 [TaGeS₅^–] layers separated from one another by alkali metal cations (A⁺). Each layer is made up of tantalum centered sulfur octahedra and pairs of edge‐sharing germanium centered sulfur tetrahedra. The classical charge valence of these compounds should be represented by [A⁺][(Ta⁵⁺)(Ge⁴⁺)(S^2–)₅]. UV/Vis diffuse reflectance measurements indicate that they are semiconductors with optical bandgaps of ca. 2.0 eV.     

Visible‐Light‐Activated C−C Bond Cleavage and Aerobic Oxidation of Benzyl Alcohols Employing BiMXO5 (M=Mg,Cd, Ni,Co, Pb,Ca and X=V,P)

The synthesis, structure, optical and photocatalytic studies of a family of compounds with the general formula, BiMXO₅; M=Mg, Cd, Ni, Co, Pb, Ca and X=V, P is presented. The compounds were prepared by regular solid‐state reaction of constituents in the temperature range of 720–810 °C for 24 h. The compounds were characterized by powder X‐ray diffraction (PXRD) methods. The Rietveld refinement of the PXRD patterns have been carried out to establish the structure. The optical absorption spectra along with the colors in daylight have been explained employing the allowed d‐d transition. In addition, the observed colors of some of the V⁵⁺ containing compounds were explained using metal‐to‐metal charge transfer (MMCT) from the partially filled transition‐metal 3d orbitals to the empty 3d orbitals of V⁵⁺ ions. The near IR (NIR) reflectivity studies indicate that many compounds exhibit good NIR reflectivity, suggesting that these compounds can be employed as ‘cool pigments’. The experimentally determined band gaps of the prepared compounds were found to be suitable to exploit them for visible light activated photocatalysis. Photocatalytic C?C bond cleavage of alkenes and aerobic oxidation of alcohols were investigated employing visible light, which gave good yields and selectivity. The present study clearly demonstrated the versatility of the Paganoite family of compounds (BiMXO₅) towards new colored inorganic materials, visible‐light photocatalysts and ‘cool pigments’.     

Synthesis,Isolation and Crystal Structures of the Metalated Ylides [Cy3P-C-SO2Tol]M (M = Li,Na, K)

The preparation and isolation of the metalated ylides [Cy₃PCSO₂Tol]M ( ^Cy1-M ) (with M = Li, Na, K) are reported. In contrast to its triphenylphosphonium analogue the synthesis of ^Cy1-M revealed to be less straight forward. Synthetic routes to the phosphonium salt precursor ^Cy1 - H₂ via different methods revealed to be unsuccessful or low-yielding. However, nucleophilic attack of the ylide Cy₃P = CH₂ at toluenesulfonyl fluoride under basic conditions proved to be a high-yielding method directly leading to the ylide ^Cy1-H . Metalation to the yldiides was finally achieved with strong bases such as nBuLi, NaNH₂, or BnK. In the solid state, the lithium compound forms a tetrameric structure consisting of a (C–S–O–Li)₄ macrocycle, which incorporates an additional molecule of lithium iodide. The potassium compound forms a C₄-symmetric structure with a (K₄O₄)₂ octahedral prism as central structural motif. Upon deprotonation the P–C–S linkage undergoes a remarkable contraction typical for metalated ylides.     

Reactions in Anhydrous Liquid Ammonia: Syntheses and Crystal Structures of [M(NH3)8]I2 (M = Eu,Yb) with Bicapped Trigonal-Prismatic Octaammine Lanthanoid(II) Cations

The compounds [M(NH₃)₈]I₂ (M = Eu, Yb) were obtained from reactions in anhydrous liquid ammonia solutions as side products. They were characterized by single-crystal X-ray diffraction and found to be isotypic to the compounds [Ca(NH₃)₈]X₂ (X = Cl, Br, I). The coordination sphere of the lanthanoid(II) cations is not square-antiprismatic but much better described as bicapped trigonal-prismatic. In contrast, quantum-chemical gas-phase calculations show the square-antiprismatic coordination polyhedron (point group S₈) to be energetically favored over the bicapped trigonal prism and the latter is not even a true local minimum. Obviously, hydrogen bonding and eventually other weak interactions have an impact on the observed bicapped trigonal-prismatic coordination sphere of the [M(NH₃)₈]²⁺ cations in the solid state.     

Reactions of [ReOX3(PPh3)2] Complexes (X = Cl,Br) with Phenylacetylene and the Structures of the Products

Oxorhenium(V) complexes [ReOX₃(PPh₃)₂] (X = Cl, Br) react with phenylacetylene under formation of complexes with ylide‐type ligands. Compounds of the compositions [ReOCl₃(PPh₃){C(Ph)C(H)(PPh₃)}] ( 1 ), [ReOBr₃(OPPh₃){C(Ph)C(H)(PPh₃)}] ( 2 ), and [ReOBr₃(OPPh₃){C(H)C(Ph)(PPh₃)}] ( 3 ) were isolated and characterized by X‐ray diffraction. They contain a ligand, which was formed by a nucleophilic attack of released PPh₃ at coordinated phenylacetylene. The structures of the products show that there is no preferable position for this attack. Cleavage of the Re–C bond in 3 and dimerization of the organic ligand resulted in the formation of the [{(PPh₃)(H)CC(Ph)}₂]²⁺ cation, which crystallized as its [(ReOBr₄)(OReO₃)]^2– salt.     

Die Reaktionen von M[BF4] (M = Li,K) und (C2H5)2O·BF3 mit (CH3)3SiCN. Bildung von M[BFx>(CN)4—x] (M = Li,K; x = 1, 2) und (CH3)3SiNCBFx(CN)3—x, (x = 0, 1)

The Reactions of M[BF₄] (M = Li, K) and (C₂H₅)₂O·BF₃ with (CH₃)₃SiCN. Formation of M[BF_x(CN)_4—x] (M = Li, K; x = 1, 2) and (CH₃)₃SiNCBF_x(CN)_3—x, (x = 0, 1) The reaction of M[BF₄] (M = Li, K) with (CH₃)₃SiCN leads selectively, depending on the reaction time and temperature, to the mixed cyanofluoroborates M[BF_x(CN)_4—x] (x = 1, 2; M = Li, K). By using (C₂H₅)₂O·BF₃ the synthesis yields the compounds (CH₃)₃SiNCBF_x(CN)_3—x x = 0, 1. The products are characterized by vibrational and NMR‐spectroscopy, as well as by X‐ray diffraction of single‐crystals: Li[BF₂(CN)₂]·2Me₃SiCN Cmc2₁, a = 24.0851(5), b = 12.8829(3), c = 18.9139(5) Å V = 5868.7(2) ų, Z = 12, R₁ = 4.7%; K[BF₂(CN)₂] P4₁2₁2, a = 13.1596(3), c = 38.4183(8) Å, V = 6653.1(3) ų, Z = 48, R₁ = 2.5%; K[BF(CN)₃] P1¯, a = 6.519(1), b = 7.319(1), c = 7.633(2) Å, α = 68.02(3), β = 74.70(3), γ = 89.09(3)°, V = 324.3(1) ų, Z = 2, R₁ = 3.6%; Me₃SiNCBF(CN)₂ Pbca, a = 9.1838(6), b = 13.3094(8), c = 16.840(1) Å, V = 2058.4(2) ų, Z = 8, R₁ = 4.4%     

(A19N7)[In4]2 (A = Ca,Sr) and (Ca4N)[In2]: Synthesis,Crystal Structures,Physical Properties,and Chemical Bonding

Single phase powders of (A₁₉N₇)[In₄]₂ (A = Ca, Sr) and (Ca₄N)[In₂] were prepared by reaction of melt beads of the metallic components with nitrogen. The crystal structure of (Ca₁₉N₇)[In₄]₂ was refined based on neutron and X‐ray powder diffraction data. The crystal structure of (Sr₁₉N₇)[In₄]₂ was solved from the X‐ray powder pattern. The structure refinements in combination with results from chemical analyses ascertain the compositions. The compounds (A₁₉N₇)[In₄]₂ (A = Ca, Sr) are isotypes of (Ca₁₉N₇)[Ag₄]₂; (Ca₁₉N₇)[In₄]₂ is probably identical to the earlier reported (Ca_18.5N₇)[In₄]₂. The crystal structure of the isotypes (A₁₉N₇)[In₄]₂ (A = Ca, Sr; cubic, , Ca: a = 1471.65(3) pm; Sr: a = 1561.0(1) pm) contains isolated [In₄] tetrahedra embedded in a framework of edge‐ and vertex‐sharing (A₆N) octahedra. Six of these octahedra are condensed by edge‐sharing around one central A²⁺ ion to form “superoctahedra” (A₁₉N₆) which are connected three‐dimensionally via further octahedra by corner‐sharing. The crystal structure of (Ca₄N)[In₂] (tetragonal, I4₁/amd, a = 491.14(4) pm, c = 2907.7(3) pm) consists of alternating layers of perovskite type slabs of vertex‐sharing octahedra (Ca₂Ca_4/2N) and parallel arranged infinite zigzag chains equation/tex2gif-stack-1.gif[In₂]. In the sense of Zintl‐type counting the compounds (A²⁺)₁₉(N^3?)₇[(In^2.125?)₄]₂ present an electron excess, (Ca²⁺)₄(N^3?)[(In^2.5?)₂] is electron deficient. Metallic properties are supported by electrical resistivity and magnetic susceptibility measurements. The analysis of the electronic structures gives evidence for the existence of homoatomic interactions In–In and significant heteroatomic metal–metal interactions Ca–In which favor the deviations of the title compounds from the (8 – N) rule.     

Nd0.67M0.33MnO3(M=Mg,Ca,Sr,Ba)的制备、结构与电性

本文通过共沉淀工艺合成了系列陶瓷化合物Nd_0.67M_0.33MnO₃(M=Mg,Ca,Sr,Ba)。与传统的陶瓷法相比，其成相温度降低了400℃。经X射线衍射分析表明，所得化合物为立方钙钛矿结构，各化合物的成相温度范围受碱土二价金属离子(M²⁺)的影响。样品的四极法电阻率测试结果表明：M²⁺的离子半径对样品的导电性起决定作用，并提出了反铁磁性(AF)与铁磁性(AF)等磁性结构假设，解释了该系列化合物的导电性。     

甲烷氧化偶联La－Me－O（Me＝Mg，Ca，Sr，Ba）系催化剂表面氧种的研究

利用ＣＯ_２－ＴＰＤ法考察了Ｌａ－Ｍｅ－Ｏ（Ｍｅ＝Ｍｇ，Ｃａ，Ｓｒ，Ｂａ）系催化剂的表面碱性，并用Ｏ_２－ＴＰＤ、ＣＨ_４－ＴＰＤ法对该体系的表面活性氧种进行了表征，并与催化性能相关联。结果表明，Ｌａ－Ｂａ－Ｏ催化剂由于表面强碱性中心数目多，产生活性氧种的数目也多，有利于甲烷的活化，因而具有最高的甲烷转化率和Ｃ_２烃选择性。脉冲反应表明，在无气相氧存在下，表面晶格氧参与了氧化偶联，而且是选择氧化的活性氧种。     

Polymorphie bei APd2X2-Verbindungen (A = Sr,Ba; X = As,Sb)

Polymorphism of APd₂X₂-Compounds (A = Sr, Ba; X = As, Sb) SrPd₂Sb₂ crystallizes at room temperature in the CaBe₂Ge₂-type structure (lattice constants see “Inhaltsübersicht”); a high-temperature modification with ThCr₂Si₂-type structure was obtained by quenching samples from above 730°C. The same structure was found for the high-temperature modification of BaPd₂As₂ which can be prepared by quenching from above 720°C. For (ThCr₂Si₂-structure) no phase transition could be observed.     

MO-RE2O3-B2O3(M=Mg,Ca,Sr,Ba;RE=La,Eu,Gd)玻璃的发光性质

在空气中采用高温固相反应方法合成的17MO－（8-x-y)-75B2O3-xGd2O3(MLBEG,M-Mg,Ca,Sr,Ba)玻璃，在紫外光（λex=350nm)激发下发射蓝光和红光，在绿色光（λex=532nm)激发下发射红光，电子自旋共振谱研究表明玻璃体系中有Eu^2 离子存在，蓝色区的宽带发射是Eu^2 离子的5d-4f跃迁发射：红色区的窄带发射是Eu^3 离子的5Do-7FJ(J=1,2,3,4)跃迁发射，发现玻璃中的碱土金属离子对Eu^3 /Eu^2 离子的比例有很大影响，选择不同的碱土金属离子可以调节玻璃蓝色光和红色光的相对发射强度，MLBEG玻璃的发光性质可用于转换太阳能，增强植物的光合作用。