Phase equilibria,charge transport,and mass transport in Sr<Subscript>4</Subscript>Nb<Subscript>2</Subscript>O<Subscript>9</Subscript>-“M<Subscript>4</Subscript>Nb<Subscript>2</Subscript>O<Subscript>9</Subscript>” (M = Cd,Cu, Ni,and Zn) systems

Homogeneous fields of Sr_{4 − x} M _x Nb₂O₉ (M = Cd, Cu, Ni, or Zn) solid solutions were determined using powder X-ray diffraction. Phase fields were plotted proceeding from the tolerance factor t and electronegativity ratio $ \bar k_A /\bar k_B $ \bar k_A /\bar k_B with a satisfactory fit of experimental results. Thermogravimetry was used to establish the major kinetic laws of solid-phase synthesis (conversion, rate-controlling stage, and effective activation energy) in (4 − x)SrCO₃ + xMO + Nb₂O₅ powdery mixtures. Direct radiometry was used to determine ⁹⁰Sr, ⁶³Ni, and ⁶⁵Zn self-diffusion coefficients in solid solutions based on the Sr₄Nb₂O₉ phase. Electrical conductivity was measured as a function of temperature for all Sr₄Nb₂O₉-“M₄Nb₂O₉” samples. The conductivity of Sr_{4 − x} M _x Nb₂O₉ (M = Cd, Cu, Ni, or Zn) solid solutions has a mixed ion-electron character.     

Synthesis and characterization of new metal(II) complexes with formates and some nitrogen donor ligands

New mixed-ligands complexes with empirical formulae: M(2,4′-bpy)₂L₂·H₂O (M(II)Zn, Cd), Zn(2-bpy)₃L₂·4H₂O, Cd(2-bpy)₂L₂·3H₂O, M(phen)L₂·2H₂O (where M(II)=Mn, Ni, Zn, Cd; 2,4′-bpy=2,4′-bipyridine, 2-bpy=2,2′-bipyridine, phen=1,10-phenanthroline, L=HCOO⁻) were prepared in pure solid state. They were characterized by chemical, thermal and X-ray powder diffraction analysis, IR spectroscopy, molar conductance in MeOH, DMF and DMSO. Examinations of OCO⁻ absorption bands suggest versatile coordination behaviour of obtained complexes. The 2,4′-bpy acts as monodentate ligand; 2-bpy and phen as chelating ligands. Thermal studies were performed in static air atmosphere. When the temperature raised the dehydration processes started. The final decomposition products, namely MO (Ni, Zn, Cd) and Mn₃O₄, were identified by X-ray diffraction.     

The Tetrachloridoaurates(III) of Zinc(II) and Cadmium(II)

The first salt‐like compounds of dications with [AuCl₄]^– anions are reported. The compounds Zn[AuCl₄]₂ · (AuCl₃)_1.115 ( 1 ) and Cd[AuCl₄]₂ ( 2 ) are obtained from reactions of MCl₂ (M = Zn, Cd) and elemental gold in liquid chlorine at ambient temperature under autogenous pressure and subsequent annealing at 230 °C. The structure of 1 represents an incommensurately modulated composite [superspace group C2/c(α0γ)0s] built of two subsystems. The first subsystem contains chains of zinc(II) tetrachloridoaurate(III), which feature a slightly distorted octahedral coordination of Zn and can be described by the Niggli formula ¹_∞{Zn[AuCl₄]_1/1[AuCl₄]_2/2}. The second subsystem consists of Au₂Cl₆ molecules, which are located in channels built up by the first subsystem. The structural parameters of the hosted Au₂Cl₆ molecules show only small deviations from neat AuCl₃. The crystal structure of Cd[AuCl₄]₂ ( 2 ) consists of chains built of Cd²⁺ ions coordinated by bridging [AuCl₄]^– anions and alternating Cd‐Au sequence. Cd has a distorted octahedral coordination environment.     

Solvolthermal Syntheses and Crystal Structures of Three Linear Trinuclear Schiff Base Complexes of Zinc(II) and Cadmium(II)

Three linear trinuclear Schiff base complexes, {Zn[Zn(CH₃COO)(C₁₇H₁₆N₂O₂)]₂} ( 1 ), {Zn[Zn(CH₃COO)(C₂₅H₂₀N₂O₂)]₂} ( 2 ), and {Cd[Cd(CH₃COO)(C₁₈H₁₈N₂O₂)]₂} ( 3 ), were synthesized for the first time under solvolthermal conditions. Their structures have been characterized by elemental analyses, X-ray single crystal determinations, and infrared spectroscopy. There are three bridges across the M-M atom pairs (M is Zn for 1 and 2 , or Cd for 3 ) in each complex, involving two O atoms of a Schiff base ligand (N,N′-bis(salicylidene)-1, 3-propanediaminate (SALPD^2-) for 1 , N, N′-bis(2-hydroxy-naphthalmethenylimino)-1, 3-propanediaminate (NAPTPD^2-) for 2 , and N,N′-bis-(salicylidene)-1,4-butanediaminate (SALBD^2-) for 3 ), and an O-C-O moiety of a μ-acetato group. In each of the complexes, the central M²⁺ ion is located on an inversion center and has a distorted octahedral coordination involving four bridging O atoms from two Schiff base ligands in the equatorial plane and one O atom from each bridging acetate group in the axial positions. The coordination around the terminal M²⁺ ions is irregular square pyramidal, with two O atoms and two N atoms of the Schiff base ligand in the basal plane and one O atom from an acetate group in the apical position. The acetate bridges linking the central and terminal M²⁺ ions are mutually trans. The M…M distances are 3.050(3) Å in 1 , 3.139(2) Å in 2 , and 3.287(6) Å in 3 .     

Experimental evidences for some unusual divalent cation complexes of valinomycin

From extraction experiments and γ-activity measurements, the exchange extraction constants corresponding to the general equilibrium M ²⁺ (aq) + 1 · Sr²⁺ (nb) ⇄ 1 · M ²⁺ (nb) + Sr²⁺ (aq) taking place in the two-phase water-nitrobenzene system (M ²⁺ = Cu²⁺, Zn²⁺, Cd²⁺, Pb²⁺, UO₂ ²⁺, Fe²⁺, Co²⁺, and Ni²⁺; 1 = valinomycin; aq = aqueous phase, nb = nitrobenzene phase) were evaluated. Moreover, the stability constants of the 1 · M ²⁺ complexes in water saturated nitrobenzene were calculated; they were found to increase in the order Fe²⁺ < Cd²⁺, Co²⁺ < Ni²⁺ < UO₂ ²⁺, Zn²⁺ < Cu²⁺ < Pb²⁺.     

Reactions of neodymium(ii), dysprosium(ii), and thulium(ii) diiodides with cyclopentadiene. Molecular structures of complexes CpTmI2(THF)3 and [NdI2(THF)5]+[NdI4(THF)2]–

The reactions of LnI₂ (Ln = Nd (1) or Dy (2)) with cyclopentadiene (CpH) in THF at 0 °C afforded the CpLnI₂(THF)₃ complexes in 65—67% yields. The reaction of thulium diiodide (3) with an excess of CpH at 60 °C produced CpTmI₂(THF)₃, Cp₂TmI(THF)₂, and TmI₃(THF)₃ in 21, 58, and 63% yields, respectively. The reactions of 1 and 2 with pentamethylcyclopentadiene (Cp*H) in THF were accompanied by disproportionation giving rise to the Cp*₂LnI(THF)₂ and LnI₃(THF) _x complexes. Neodymium triiodide was isolated in the ionic form [NdI₂(THF)₅]⁺[NdI₄(THF)₂]^–. Its structure and the structure of CpTmI₂(THF)₃ were established by X-ray diffraction analysis.     

Novel heterodinuclear transition metal macrocyclic complexes: syntheses,characterization and crystal structures

Two unsymmetrical, macrocyclic, heterodinuclear complexes, [Cu^IIM^II(L)]?(ClO₄)₂·nH₂O (n?=?3; M?=?Zn, Cd) have been obtained by cyclocondensation of N,N′-bis(3-formyl-5-n-butylsalicylidene)ethylenediimine and 1,3-diaminopropane in the presence of M²⁺. The structures of both complexes were determined by X-ray diffraction techniques. In each complex, two metals are located in the tetraimine macrocyclic cavity, and a water molecule and a perchlorate group are separately coordinated to the metal ions on the same side of the ring. Coordination geometry around each metal is approximately square pyramidal. ESMS spectra were used to characterize the complexes and isotopic distributions were investigated.     

On the role of interlayer atoms and molecular water in formation of crystal structure of salts of uranoarsenic acid HAsUO<Subscript>6</Subscript> · 4H<Subscript>2</Subscript>O

A number of uranoarsenates of alkali metals (Li⁺, Na⁺, K⁺, Rb⁺, Cs⁺, NH₄⁺), alkaline-earth metals (Mg²⁺, Ca²⁺, Sr²⁺, Ba²⁺), and rare-earth metals (Y³⁺, La³⁺, Ln³⁺) of the composition M ^k (AsUO₆) _k · nH₂O were prepared by ion exchange in the M ^k -HAsUO₆ · 4H₂O system. On the basis of the data of X-ray diffraction, IR spectroscopy, thermal analysis, and elemental analysis, molecular water and the nature of the interlayer atom M ^k were found to play the key role in structure formation for the compounds.     

Experimental evidences for some unusual divalent cation complexes of valinomycin

From extraction experiments and γ-activity measurements, the exchange extraction constants corresponding to the general equilibrium M ²⁺ (aq) + 1 · Sr²⁺ (nb) ⇄ 1 · M ²⁺ (nb) + Sr²⁺ (aq) taking place in the two-phase water-nitrobenzene system (M ²⁺ = Cu²⁺, Zn²⁺, Cd²⁺, Pb²⁺, UO₂ ²⁺, Fe²⁺, Co²⁺, and Ni²⁺; 1 = valinomycin; aq = aqueous phase, nb = nitrobenzene phase) were evaluated. Moreover, the stability constants of the 1 · M ²⁺ complexes in water saturated nitrobenzene were calculated; they were found to increase in the order Fe²⁺ < Cd²⁺, Co²⁺ < Ni²⁺ < UO₂ ²⁺, Zn²⁺ < Cu²⁺ < Pb²⁺. Correspondence: Emanuel Makrlík, Faculty of Applied Sciences, University of West Bohemia, Pilsen, Czech Republic.     

Innerkomplexe mit Metallamidbindungen. II. Zink- und Chrom(II)-Komplexe des 2-[β-(Phenyl-amino)-äthyl]-pyridins

The preparation of uncharged complexes with metal amide bonds of type [MeN₄]^±0 (Me = Zn²⁺, Cr²⁺ is reported. These compounds are obtained by the interaction between Zn(C₆H₅)₂ or Cr(C₆H₅)₃ · 3 THF and 2-[β-(phenyl-amino)-ethyl]-pyridine (I). The same complexes are formed by the reaction between ZnCl₂ · 2 THF, CrBr₂ · 2 THF, or CrCl₃ · 3 THF and the lithium amide (II), which is prepared from (I) and phenyl lithium. The structure of the chromium(II) complex is discussed on the basis of magnetic and visible absorption measurements.     

Structural variation from linear,layer to 3D framework: Syntheses,structures and luminescence

Self‐assembly of Zn (II) or Cd (II) nitrates, flexible bis (pyridyl)‐diamine, as well as arenesulfonic acids, leads to the formation of ten coordination polymers, namely, [Zn(L1)(H₂O)₃]·2(p‐TS)·2H₂O ( 1 ), [Zn(L1)(H₂O)₂]·2(p‐TS)·2H₂O ( 2 ), [Zn(L1)₂(p‐TS)₂] ( 3 ), [Zn(H₂L1)(H₂O)₄]·2(1,5‐NDS)·2H₂O ( 4 ), [Zn(H₂L2)(H₂O)₄]·2(1,5‐NDS)·4MeOH ( 5 ), [Cd(L1)(p‐TS)(NO₃)]·H₂O ( 6 ), [Cd(L1)(1,5 ‐NDS)_0.5(H₂O)]·0.5(1,5‐NDS)·H₂O ( 7 ), [Cd(L2)(H₂O)₂]·(p‐TS)·(NO₃)·3H₂O ( 8 ), [Cd(L2)(1,5‐NDS)] ( 9 ) and [Cd(L2)(1,5‐NDS)]·MeOH ( 10 ) (L1 = N,N′‐bis (pyridin‐4‐ylmethyl) ethane‐1,2‐diamine, L2 = N,N′‐bis (pyridin‐3‐ylmethy l)ethane‐1,2‐diamine, p‐HTS = p‐toluenesulfonic acid, 1,5‐H₂NDS = 1,5‐naphthalene disulfonic acid), which have been characterized by elemental analysis, IR, TG, PL, powder and single‐crystal X‐ray diffraction. Complexes 1 , 4 , 5 and 6 present linear or zigzag chain structures accomplished by the interconnection of adjacent M (II) cations through L1 ligands or protonated H₂L1²⁺/H₂L2²⁺ cations, while complexes 2 , 3 and 8 show similar (4,4) layer motifs constructed from the connection of M (II) cations through L1 and L2. The same coordination modes of L1 and L2 in complexes 7 and 9 join adjacent Cd (II) cations to form double chain structures, which are further connected by bis‐monodentate 1,5‐NDS^2? dianions into different (6,3) and (4,4) layer motifs. The L2 molecules in complex 10 join adjacent Cd (II) cations together with 1,5‐NDS^2? dianions to form 3D network with hxl topology. Therefore, the diverse coordination modes of the bis (pyridyl) ligand with chelating spacer and the feature of different arenesulfonate anions can effectively influence the architectures of these complexes. Luminescent investigation reveals that the emission maximum of these complexes varies from 374 to 448 nm in the solid state at room temperature, in which complexes 4 , 5 , 7 , 9 and 10 show average luminescence lifetimes from 7.20 to 14.82 ns. Moreover, photocatalytic properties of complexes 7–10 towards Methylene blue under Xe lamp irradiation are also discussed.     

Enhancement of the Up-conversion Luminescence of 12CaO · 7Al2O3:Tm3+/Yb3+ Doped with Alkaline Earth Metal Ions

12CaO?·?7Al₂O₃ doped with lanthanide is characterized by remarkable and technologically important up-conversion emission. However, the low up-conversion efficiency still remains the main limitation for practical applications. To improve the efficiency, bivalent alkaline earth ions (Mg²⁺, Sr²⁺, Ba²⁺)-tridoped Tm³⁺/Yb³⁺/12CaO?·?7Al₂O₃ were synthesized through a high-temperature solid-state reaction. The up-conversion luminescence properties of the samples were investigated by X-ray diffraction, fluorescence spectral measurement pump power, and fluorescence decay curves. The luminescence intensity of samples was significantly enhanced by bivalent alkaline earth ions. 12CaO?·?7Al₂O₃ doped with Sr²⁺ ions has stronger effects on up-conversion enhancement, which is better than Mg²⁺ and Ba²⁺. The up-conversion emission intensity was enhanced by 318 times and the red emission intensity by 218 times with 10?mol% Sr²⁺ ion. Additionally, the blue and red up-conversion emission peaks at 475 and 650?nm corresponding to energy transitions of ¹G₄ → ³H₆ and ¹G₄ → ³F₄, ³F₂ → ³H₆ were characterized using steady-state rate equations.     

Syntheses and Structural Characterization of 1D Chain and 1D Ladder Coordination Polymers Assembled from Exo‐bidentate Imidazolyl Ligands

Five novel coordination polymers, [(Cu(L¹)₂OH) · Cl · 3H₂O] ( 1 ) [L¹ = bis(N‐imidazolyl)methane], [Cd(L¹)₂(NCS)₂] ( 2 ), [Zn(L¹)₂(NCS)₂] ( 3 ), [Cu(L¹)₂(NO₃)₂] ( 4 ), and [Cu(L²)_1.5(NCS)₂] ( 5 ) [L² = 1,4‐bis(N‐imidazolyl)butane] were obtained from self‐assembly of the corresponding metal salts with flexible ligands and their structures were fully characterized by X‐ray diffraction (XRD) analysis, Fourier Transform Infrared (FT‐IR) spectroscopy, elemental analysis and thermogravimetric (TGA) measurements. X‐ray diffraction analyses revealed that complexes 1 , 2 , 3 , and 4 exhibit 1D double‐stranded chain structures, which result from doubly bridged [CuOH], [M(NCS)₂] (M = Cd, Zn), and [Cu(NO₃)₂] units, respectively. The polymeric copper complex 5 displays 1D ladder structure., These complexes, with the exception of complex 1 , are stable up to 300 °C.     

Investigation of s, p, d-element Niobates and Their Solid Solution Formation Processes by Thermal Analysis

The binary and ternary systems M'O(M'CO₃)-Nb₂O₅ and M'O(M'CO₃)-MO-Nb₂O₅, where M'=Ca,Sr and Ba and M=Cu, Ni, Cd, Zn and Pb, were investigated by means of thermal analysis in the temperature range 20–1500°C. The boundaries of stability of the solid solutions Sr_2−xMe_xNb₂O₇,Sr_2−xM_xNb₂O₇, Sr_4−xM_xNb₂O₉ and Sr_6−xM_xNb₂O₁₁ were determined by means of X-ray diffraction, and IR and Raman spectroscopy. The possibility of prognostication of the phase fields of stable solid solutions by calculation from the diagrams of the ‘comparative electronegativity of atoms vs. tolerance factor’ was demonstrated. The kinetic parameters of the interactions in theSrCO₃+MO+Nb₂O₅ powder mixtures were established. This revised version was published online in August 2006 with corrections to the Cover Date.     

Synthesis of maghemite nano-particles and its application as radionuclidic adsorbant to purify <Superscript>109</Superscript>Cd radionuclide

Maghemite nano-particles were synthesized by a solid-state chemical reaction for its highly selective use as, cyclotron-produced, ¹⁰⁹Cd (462.9 days) purification method of choice. ¹⁰⁹Cd radiochemical separation starts with Ag activities precipitated with HCl 0.0015 M followed by, on a second step, ¹⁰⁹Cd separation from Cu carrier and ⁶⁵Zn (243.8 days) using Ca (NO₃)₂ 0.01 M. Experimental parameters such, pH and sorbent concentration, on ¹⁰⁹Cd extraction efficiency were investigated. Phase morphology, nanostructure and size of nano-particles were studied by X-ray diffraction (XRD) and scanning electron microscopy (SEM). A 10–20 nm average grain size was derived from XRD line broadening and SEM data. Heat treatment on Fe³⁺:Fe²⁺ ratios equal to 2:1, produced powders, resulting in tetragonal (maghemite) structure at 300 °C and rhombohedra (hematite) at 600 °C. ¹⁰⁹Cd chemical and radionuclidic purity were determined by ICP-AES and HPGe detector gamma-ray spectrometry. The overall recovery and radionuclide purity were 80.0% from obtained 129.63 kBq/C MeV (70 kBq/μAh) initial activity and 91.4%, respectively.     

Reduction of 2,5-di-tert-butylcyclopentadienone and pyridine with thulium diiodide. Structures of the complexes TmI2(THF)2[η5-But2C5H2O]TmI2(THF)3 and [TmI2(C5H5N)4]2(μ2-N2C10H10)

Reduction of 2,5-di-tert-butylcyclopentadienone with two equivalents of thulium diiodide in tetrahydrofuran afforded the binuclear thulium(iii) complex with the cyclopentadienyl oxide ligand, viz., TmI₂(THF)₂[⁵-Bu^t ₂C₅H₂O]TmI₂(THF)₃ (1). Shielding of the carbonyl carbon atom with two tert-butyl substituents prevents pinacolization of the ketyl radical anions that formed upon one-electron reduction of cyclopentadienone. The reaction of thulium diiodide with an excess of pyridine in tetrahydrofuran gave a product of reductive coupling of two pyridine radical anions, viz., [TmI₂(C₅H₅N)₄]₂(₂-N₂C₁₀H₁₀) (2). The structures of complexes 1 and 2 were established by single-crystal X-ray diffraction analysis.     

Microwave synthesis and photoluminescent properties of Sr2CeO4/Ln3+ (Ln = Er, Ho, Tm)

Sr₂CeO₄/Ln³⁺ (Ln = Er, Ho, Tm) phosphors were synthesized with the microwave radiation method for the first time. The luminescent properties of the samples were investigated and the up-conversion luminescence of Er³⁺, Ho³⁺ and Tm³⁺ doped Sr₂CeO₄ phosphors was observed. The spectra indicate that the energy transfer takes place from the triplet excited state of MLCT (metal-to-ligand charge transfer) state for Sr₂CeO₄ (sensitizer) to the rare earth ions (activator). __________ Translated from Journal of Hebei Normal University (Natural Science Edition), 2007, 31(2): 212–216 [译自: 河北师范大学学报 (自然科学版)]     

Metal Chelates of N‐(2‐pyridylmethyl)iminodiacetate(2‐) Ion (pmda). Part II. Ternary pmda Chelates with M = Co,Cu or Zn and Creatinine as Auxiliary Ligand

The compounds [Cu(pmda)(crea)]·H₂O ( 1 ), [Zn(pmda)(crea)]·H₂O ( 2 ) and [Co(pmda)(crea)(H₂O)]·H₂O ( 3 ) were prepared and characterized by thermal, spectral and X‐ray diffraction methods. In compounds 1 and 2 the M^II coordination is of type 4+1 and approaches to a trigonal bipyramid (71.85 and 86.18 %, respectively) with rather linear N(pmda)‐M^II‐N(crea) trans‐apical angles, but with different longest coordination bond (Cu‐O(pmda) or Zn‐N(apliphatic, pmda), respectively). Both compounds are isotypic and one intra‐molecular interligand N‐H···O interaction reinforces the molecular recogniton crea‐M^II(pmda) chelate. In contrast, the compound 3 exhibits an octahedral coordination, imposed by the 3d⁷ electronic configuration of the cobalt(II) atom, and the crea‐chelate recognition involves the Co‐N(crea) coordination bond and one intramolecular ‘bifurcated’ H‐bonding interaction between one N‐H(crea) bond and one O(pmda) plus the O(aqua) atoms as ‘acceptors’.     

Systematische Studie zu den Koordinationseigenschaften des Guanidin‐Liganden Bis(tetramethylguanidino)propan mit den Metallen Mangan,Cobalt, Nickel,Zink, Cadmium,Quecksilber und Silber

The transition metal complexes with the ligand 1,3‐bis(N,N,N′,N′‐tetramethylguanidino)propane (btmgp), [Mn(btmgp)Br₂] ( 1 ), [Co(btmgp)Cl₂] ( 2 ), [Ni(btmgp)I₂] ( 3 ), [Zn(btmgp)Cl₂] ( 4 ), [Zn(btmgp)(O₂CCH₃)₂] ( 5 ), [Cd(btmgp)Cl₂] ( 6 ), [Hg(btmgp)Cl₂] ( 7 ) and [Ag₂(btmgp)₂][ClO₄]₂·2MeCN ( 8 ), were prepared and characterised for the first time. The stoichiometric reaction of the corresponding water‐free metal salts with the ligand btmgp in dry MeCN or THF resulted in the straightforward formation of the mononuclear complexes 1 – 7 and the binuclear complex 8 . In complexes with M^II the metal ion shows a distorted tetrahedral coordination whereas in 8 , the coordination of the M^I ion is almost linear. The coordination behavior of btmgp and resulting structural parameters of the corresponding complexes were discussed in an comparative approach together with already described complexes of btmgp and the bisguanidine ligand N¹,N²‐bis(1,3‐dimethylimidazolidin‐2‐ylidene)‐ethane‐1,2‐diamine (DMEG₂e), respectively.     

Crystal Chemistry of the M11+,2+–M22+,3+–(H)‐Arsenites: the First Cadmium(II) Arsenite,Na4Cd7(AsO3)6

The crystal structures among M1–M2–(H)‐arsenites (M1 = Li⁺, Na⁺, K⁺, Rb⁺, Cs⁺, Ca²⁺, Sr²⁺, Ba²⁺, Cd²⁺, Pb²⁺; M2 = Mg²⁺, Mn^2+,3+, Fe^2+,3+, Co²⁺, Ni²⁺, Cu²⁺, Zn²⁺) are less investigated. Up to now, only the structure of Pb₃Mn(AsO₃)₂(AsO₂OH) was described. The crystal structure of hydrothermally synthesized Na₄Cd₇(AsO₃)₆ was solved from the single‐crystal X‐ray diffraction data. Its trigonal crystal structure [space group R$\bar{3}$ , a = 9.5229(13), c = 19.258(4) Å, γ = 120°, V = 1512.5(5) ų, Z = 3] represents a new structure type. The As atoms are arranged in monomeric (AsO₃)^3– units. The surroundings of the two crystallographically unique sodium atoms show trigonal antiprismatic coordination, and two mixed Cd/Na sites are remarkably unequal showing tetrahedral and octahedral coordinations. Despite the 3D connection of the AsO₃ pyramids, (Cd,Na)O_x polyhedra and NaO₆ antiprisms, a layer‐like arrangement of the Na atoms positioned in the hexagonal channels formed by CdO₄ deformed tetrahedra and AsO₃ pyramids in z = 0, 1/3, 2/3 is to be mentioned. These pseudo layers are interconnected to the 3D network by (Cd,Na)O₆ octahedra. Raman spectra confirmed the presence of isolated AsO₃ pyramids.