Structure of Y3TaNi6+xAl26: a filled-up substitution variant of the BaHg11 type

The crystal structure of Y₃TaNi_6+xAl₂₆ (refined composition Y₄TaNi_6+[7]Al_20+[6]) was determined by single-crystal X-ray diffraction (λ(Mo K) −0.71073 A. μ −17.827 mm¹, F(000) = 700, T = 293 K, wR = 0.015 for [8] unique reflections). This new quaternary aluminide crystallizes with a cubic structure. Pearson code cP49-12.85, (221) Pm-3m-ji'gdba, a = 8.3600(1) Å. V = 584.28(2) Å, Z = 1, M₁ = 1510.25, D_x = 4.292 mg mm¹. The structure of Y_xTaNi_6+xAl₂₆ is filled-up substitution variant of the BaHg₁₁ structure type with one additional atom site, partly occupied (around 15%) by Ni atoms, located at the centre of a cube formed by Al atoms. Distinct atom coordinates were refined for Ni and Al atoms on a site for which mixed occupation (approximately 50% Ni/50% Al) was found. The Ta atoms centre regular Al atom cuboctahedra, and the Y atoms 20-vertex polyhedra, formed by Al and Ni atoms, similar to those observed in CeMn₄Al₈ and YbFe₂Al₁₀.     

Preparation and magnetic properties of amorphous Co–Zr–B alloy nano-powders

The magnetic Co–Zr–B amorphous alloy powders, having a nearly spherical morphology with diameters <50 nm, were obtained successfully by the reduction of an aqueous solution of zirconium sulphate and cobalt chloride with an aqueous solution of sodium borohydride. XRD, selected-area electron diffraction (SAED) and differential scanning calorimetry (DSC) studies showed that the resultant were partially amorphous together with a tiny volume fraction of crystalline phases, and the main amorphous phase consisted of the Zr-based amorphous particles and the Co-based Zr-containing amorphous particles. It is found that the Co/Zr ratio in the powders was indistinguishably equal to the Co²⁺/Zr⁴⁺ ratio in the original mixed solution and the boron content of the samples increased along with the addition rate of NaBH₄ solution. The crystallization temperatures of the resultant powders were in the range of 765.1–771.3 K. The thermal stability of amorphous Co–Zr–B powder increased with increasing the zirconium content. When the Co/Zr ratio in the samples increased from 1.94 to 5.14, the saturation magnetization increased monotonously from 4.76 to 8.87 emu/g, but the coercivity increased irregularly from 15.98 to 26.81 Oe.     

LaMg2NiH7, a novel quaternary metal hydride containing tetrahedral [NiH4] complexes and hydride anions

A new ternary compound of composition LaMg₂Ni has been found and investigated with respect to structure and hydrogenation properties. It crystallizes with the orthorhombic MgAl₂Cu type structure (space group Cmcm, a=4.2266(6), b=10.303(1), c=8.360(1) Å; V=364.0(1) ų; Z=4) and absorbs hydrogen near ambient conditions (<200 °C, <8 bar) thereby forming the quaternary metal hydride LaMg₂NiH₇. Neutron powder diffraction on the deuteride revealed a monoclinic distorted metal atom substructure (LaMg₂NiD₇: space group P2₁/c, a=13.9789(7), b=4.7026(2), c=16.0251(8) Å; β=125.240(3)°, V=860.39(8) ų; Z=8) that contains two symmetry independent tetrahedral [NiD₄]⁴⁻ complexes with Ni–D bond lengths in the range 1.49–1.64 Å, and six D⁻anions in tetrahedral metal configuration with bond distances in the ranges 1.82–2.65 Å (Mg) and 2.33–2.59 Å (La). The compound constitutes a link between metallic ‘interstitial’ hydrides and non-metallic ‘complex’ metal hydrides.     

Electrochemical properties of the MmNi3.55Mn0.4Al0.3Co0.75−xFex (x = 0.55 and 0.75) compounds

The hydrogen storage alloys MmNi_3.55Mn_0.4Al_0.3Co_0.75−xFe_x (x = 0.55 and 0.75) were used as negative electrodes in the Ni-MH accumulators. The chronopotentiommetry and the cyclic voltammetry were applied to characterize the electrochemical properties of these alloys. The obtained results showed that the substitution of the cobalt atoms by iron atoms has a good effect on the life cycle of the electrode. For the MmNi_3.55Mn_0.4Al_0.3Co_0.2Fe_0.55 compound, the discharge capacity reaches its maximum of 210 mAh/g after 12 cycles and then decreases to 190 mAh/g after 30 charge–discharge cycles. However, for the MmNi_3.55Mn_0.4Al_0.3Fe_0.75 compound, the discharge capacity reaches its maximum of 200 mAh/g after 10 cycles and then decreases to 160 mAh/g after 30 cycles.

The diffusion behavior of hydrogen in the negative electrodes made from these alloys was characterized by cyclic voltammetry after few activation cycles. The values of the hydrogen coefficient in MmNi_3.55Mn_0.4Al_0.3Co_0.2Fe_0.55 and MmNi_3.55Mn_0.4Al_0.3Fe_0.75 are, respectively, equal to 2.96 × 10⁻⁹ and 4.98 × 10⁻¹⁰ cm² s⁻¹. However, the values of the charge transfer coefficients are, respectively, equal to 0.33 and 0.3. These results showed that the substitution of cobalt by iron decreases the reversibility and the kinetic of the electrochemical reaction in these alloys.     

Structural, magnetic and magnetostrictive studies of Tb0.27Dy0.73(Fe1 − xAlx)2

Measurements of magnetic properties, X-ray diffraction and magnetostriction were made on Tb_0.27Dy_0.73(Fe_{1 − x}Al_x)₂ (x = 0.1, 0.2, …, 0.7) compounds. It was found that the system has the cubic MgCu₂ structure over almost the whole (Fe,Al) concentration range investigated, except for a narrow intermediate range (x = 0.4–0.6) where the hexagonal MgZn₂ structure appears. With increasing Al content x, the lattice constant a increases linearly with x. The first replacement of Fe results in a marked decrease in the Curie temperature, which is followed by a slight decrease in T_C with x. A linear decrease in magnetostriction of |λ_| − λ| at room temperature with x was also observed from 1530 × 10⁻⁶ for x=0 to 36×10⁻⁶ for x=0.3. The saturation magnetization σ_s exhibits a complex concentration dependence in the Tb_0.27Dy_0.73(Fe)_{1 − x}Al_x)₂ system: in the range x < 0.5, σ_s increases linearly with x and, for x = 0.5–0.6, σ_s decreases and then increases again. An enhancement of the magnetic ‘hardness’ in this system was also observed at low temperature.     

Relaxation mechanisms and microstructure in glass and glass-ceramics

Two LAS (Li₂O–Al₂O₃–SiO₂)-type glass-ceramics and their parent glass have been studied by isothermal mechanical spectroscopy. These materials have the same chemical composition but the two glass-ceramics differ in microstructure: one is a ‘β-quartz’ glass-ceramic whereas the other one is of ‘β-spodumene’ type. The isothermal internal friction measurements performed in a frequency sweep [10⁻⁴–31.6 Hz] with an inverted torsion pendulum, submitted to subresonant forced oscillations, at temperatures between 93 and 820 K, have revealed several mechanical relaxation peaks. A single internal friction peak is observed in the glass sample whereas two peaks occur in the ‘β-quartz’ and ‘β-spodumene’ glass-ceramics. A detailed microstructure analysis (XRD, IRTF, SEM, TEM and DTA) and dielectric loss measurements have allowed to interpret these relaxation phenomena. The mechanical relaxation peak observed in the glass (290 K for 1 Hz) is assigned to the stress-induced movement of lithium ions. In each glass-ceramic the ‘low-temperature’ peak (340 K for 1 Hz) is linked with the ion mobility in the respective main crystalline phase. As for the ‘high-temperature’ peak, its origin is totally different for the two glass-ceramics; in the ‘β-quartz’ glass-ceramic it is due to the Mg²⁺ and Zn²⁺ ion relaxation in the crystalline phase, whereas in the ‘β-spodumene’ glass-ceramic it is linked with a complex entity within the residual vitreous phase.     

Microstructural evolution during controlled ball milling of (Mg2Ni+MgNi2) intermetallic alloy

Nearly dual-phase Mg–Ni alloy fabricated by ingot metallurgy (IM) and comprising 30 vol% Mg₂Ni and 61 vol% MgNi₂ intermetallic compounds (remaining 9 vol% of unreacted Mg) was mechanically (ball) milled under controlled shearing for 10, 30, 70 and 100 h. The majority of the medium- and small-sized powder particles exhibited a relatively homogeneous microstructure of milled Mg₂Ni and MgNi₂. A fraction of large-sized particles developed the ‘core and mantel’ microstructure after milling for 70 and 100 h. The ‘core’ contains poorly milled MgNi₂ particles and the ‘mantel’ is a thoroughly milled mixture of Mg₂Ni, MgNi₂ and, possibly, residual Mg. X-ray diffraction provides evidence of nanostructurization and eventual amorphization of a fraction of a heavily ball milled Mg₂Ni phase. The remnant Mg₂Ni developed a nanocrystalline/submicrocrystalline structure. The co-existing MgNi₂ phase developed a submicrocrystalline structure within the powder particles. The results are rationalized in terms of enthalpy effects by the application of Miedema’s semi-empirical model to the phase changes in ball milled intermetallics.     

Power factor of La1−xSrxFeO3 and LaFe1−yNiyO3

The electrical conductivity (σ), Seebeck coefficient (S), and power factor (σS²) of perovskite-type LaFeO₃, La_1−xSr_xFeO₃ [0.1 ≤ x ≤ 0.4] and LaFe_1−yNi_yO₃ [0.1 ≤ y ≤ 0.6] were investigated in the temperature range of 300–1100 K to explore their possibility as thermoelectric materials. The electrical conductivity of LaFeO₃ showed semiconducting behavior, and its Seebeck coefficient changed from positive to negative around 650 K with increasing temperature. The electrical conductivity of LaFeO₃ increased with the substitutions of Sr and Ni atoms, while its Seebeck coefficient decreased. The Seebeck coefficient of La_1−xSr_xFeO₃ was positive, whereas that of LaFe_1−yNi_yO₃ changed from positive to negative with increasing Ni content. The substitutions of Sr and Ni were effective in increasing the power factor of LaFeO₃; 0.0053 × 10⁻⁴ Wm⁻¹ K⁻² for LaFeO₃ (1050 K), 1.1 × 10⁻⁴ Wm⁻¹ K⁻² for La_1−xSr_xFeO₃ (x = 0.1 at 1100 K) and 0.63 × 10⁻⁴ Wm⁻¹ K⁻² for LaFe_1−yNi_yO₃ (y = 0.1 at 1100 K).     

Hydrogen redistribution in the solid solutions ZrV2Dx, 2.2≤x≤2.7.: II. Structure of the intermediate phase: ‘Lattice liquid crystal’. A neutron-diffraction study

We have studied the crystal structure of the uncommon phase with k=0 in ZrV₂D_x, 2.2<x<2.5, which is an intermediate between the hydrogen-disordered phase and two hydrogen superstructures, ZrV₂D_<2 with k=(1/2 1/2 1/2) and ZrV₂D_>2.7 with k=(001). This phase is a primary superstructure combining the features of the disordered phase and, depending on the hydrogen concentration, one or another superstructure with k≠0. Its lattice (translational symmetry) is the same as in the disordered phase, which is k=0. Simultaneously, the lattice sites (the hydrogen arrangement in them) are prototypes of the sites of the subsequent superstructure with k≠0. Specifically, each site of the primary superstructure with k=0 is a mix of the sites with different spatial orientation of the superstructure with k≠0. In this sense the primary superstructure can be considered as a ‘lattice liquid crystal’ whereas usual superstructure with k≠0 is a ‘lattice crystal’. In addition, we have determined the crystal structure of the ‘ordered’ phase with k=(001) in ZrV₂D_2.73. It is a transitional state between the primary superstructure and the regular superstructure with the same k.     

Bulk and surface modifications of insulating poly (paraphenylene sulphide) films by ion bombardment

Thin poly(paraphenylene sulphide) (PPS) films (2 μm thick), bombarded with He⁺ (380 keV), B⁺ (350 keV) and Ar²⁺ (700 keV) at fluences ranging from 10¹² to 2 × 10¹⁶ ions cm⁻², were analysed by X-ray diffractometry, UV-visible absorption spectroscopy, electrical resistance measurements and solubility tests. The polymer gradually underwent an amorphization process indicated by the decrease in the main X-ray diffraction peak area and also lost its solubility with increasing ion fluence. This behaviour revealed the formation of cross-linking and amorphous structures. A red shift of the optical absorption threshold with increasing fluence was also observed by UV-visible spectroscopy. This trend is usually attributed to the conjugation of unsaturated carbon bonds which gives rise to non-localized π electrons. From these spectral data the gap between valence band and conduction band (optical gap E_g) using a model for amorphous semiconductors can be obtained. The conjugation process increased with fluence resulting in a decrease in the optical gap. For Ar²⁺ -bombarded samples the optical gap saturated at 0.9 eV for fluences around 10¹⁵ cm⁻². The decrease in E_g with increasing fluence is a direct indication that a new group of conducting structures is being formed in the polymeric material. Electrical measurements made immediately after 2 × 10¹⁶ Ar²⁺ cm⁻² bombardment revealed that the electrical resistivity decreased by 18 orders of magnitude in relation to the original PPS. When the bombarded samples were exposed to air the electrical conductivity decreased. This electrical instability was assigned to the free radicals present in the polymer chain after ion bombardment. This work shows that different hydrogenated amorphous carbon films can be obtained from one common polymeric matrix by judicious choice of the projectile ion stopping mechanism.     

Crystal structure and magnetism of the Y2Pd14B5 compound

The crystal structure of the ternary boride Y₂Pd₁₄B₅, space group I4₁/amd, a=8.484(2) Å, c=16.490(3) Å, V=1186.98 ų, Z=4, was refined down to R=0.0475, wR2=0.1276 from single crystal X-ray diffraction data. Two types of coordination for boron atoms were observed: the coordination sphere for the B1 atom is a trigonal prism with one additional atom; the B2 atom has only four neighboring atoms which form a square. No boron–boron contact was observed. Analysis of the Y₂Pd₁₄B₅ crystal structure shows the existence of a correlation between this structure and the Sc₄Ni₂₉B₁₀ structure type. Magnetization and AC susceptibility measurements indicate that there is no superconducting or magnetic transition in Y₂Pd₁₄B₅ down to 2 K.     

Hydrogenation of oxygen-stabilized Zr3NiOx compounds

It is shown that oxygen-stabilized compounds Zr₃NiO_x (x=0.4, 0.6, 0.8, 1.0) interact with hydrogen at ambient temperature and pressure forming saturated hydrides with a filled Re₃B-type structure. The hydrogen storage capacity decreases with increasing oxygen content from 6.65 H/f.u. for Zr₃NiO_0.4 down to 5.58 H/f.u. for Zr₃NiO_1.0. A slight decrease of the crystal lattice parameters of the parent compounds and a substantial increase of these parameters for the saturated hydrides were observed with increasing oxygen content. The partial hydrogen-induced lattice expansion, ΔV/at. H, increases from 2.333 ų for Zr₃NiO_0.4H_6.65 to 3.047 ų for Zr₃NiO_1.0H_5.58. Joint Rietveld refinement using X-ray and neutron powder diffraction data showed a distribution of deuterium atoms on similar positions as in oxygen-free Zr₃FeD_x and Zr₃CoD_x. The oxygen atoms move during deuteration from the octahedral site to one trigonal bi-pyramidal and two tetragonal interstices that are fully occupied in the saturated deuterides jointly by deuterium and oxygen. After deuterium desorption the oxygen atoms fully return to the initial octahedral site.     

Synthesis and electrode characteristics of the new composite alloys Mg2Ni-xwt.% Ti2Ni

A new composite alloy Mg₂Ni-xwt.% Ti₂Ni has been successfully synthesised using a ‘particle inlaying’ method. Scanning electron microscopy and energy dispersive spectroscopy revealed that very fine Ti₂Ni particles were inlaid onto the surface of Mg₂Ni particles by mechanical treatment and sintering. XRD showed the composite alloys were composed of primary alloys Mg₂Ni, Ti₂Ni and new phases TiNi, Ti---Mg formed in the composite procedure. The electrode characteristics of Mg₂Ni-xwt.% Ti₂Ni alloys in an alkaline solution have been investigated and compared with those of Mg₂Ni. The discharge capacity of the alloy electrode was effectively improved from 8 mA h g¹ of Mg₂Ni to 165 mA h g¹ of Mg₂Ni-40wt.% Ti₂Ni at ambient temperature, which is almost comparable with that of Ti₂Ni electrode (170 mA h g¹). It is believed that the fine Ti₂Ni particles inlaid on the surface of Mg₂Ni particles play a two-fold role: firstly, they hydride-dehydride as hydrogen storage materials themselves: secondly, they provide active sites and pathways for Mg₂Ni hydriding-dehydriding. This is supported by analysis of discharge behaviour and electrochemical impedance spectra studies.     

Optical study of praseodymium dicarboxylate [Pr(H2O)]2[O2C(CH2)3CO2]3.4H2O

Praseodymium dicarboxylate, [Pr(H₂O)]₂[O₂C(CH₂)₃CO₂]₃.4H₂O]–glutarate, Pr[glut], is synthesized by hydrothermal techniques. The title compound crystallizes in the monoclinic space group C2/c (No. 15). The rare earth cation is coordinated by nine oxygen atoms, eight oxygen atoms from the carboxylate groups and one from the water molecule. The local symmetry of Pr site is low, C_s. The absorption spectra of Pr[glut] are recorded from the visible to the far IR domain at 300, 77 and 9 K. Under various Ar⁺ laser excitations no emission is detected from ³P₀ and ¹D₂ excited levels of Pr³⁺ ion. In the low temperature absorption spectra only one electronic line is recorded for ³H₄→³P₀ transition. It confirms a unique local environment for the rare earth ion in Pr[glut]. The utility of the ‘barycenter curves’ in the attribution of electronic lines is demonstrated. Energy level scheme of 36 Stark components is deduced from the absorption spectra. The parametric calculation was performed on the whole 4f² (Pr³⁺) configuration with the starting set of crystal field parameters obtained previously for the Eu³⁺ ion in the isostructural compound. Eight free ion and nine phenomenological crystal field parameters in C_2v symmetry reproduce quite well several electronic levels of Pr³⁺ ion experimentally observed in Pr[glut]. A good r.m.s. standard deviation of 14.8 cm⁻¹ is obtained.     

The characteristics of Li(CoxNi1 − x)O2 cathode powders formed from the fine-sized Co3O4/NiO precursor powders

Li(Co_xNi_1 − x)O₂ (0 ≤ x ≤ 1) cathode powders were prepared by solid state reaction method using Co₃O₄/NiO precursor powders obtained by spray pyrolysis. The effect of the ratios of cobalt and nickel components on the characteristics of Co₃O₄/NiO precursor and Li(Co_xNi_1 − x)O₂ cathode powders were investigated. The Co₃O₄/NiO precursor powders with the ratios of cobalt and nickel components as 1/0, 0.75/0.25 and 0.5/0.5 had submicron size and regular morphologies. On the other hand, the Co₃O₄/NiO powders with the high contents of nickel component had aggregated morphologies of submicron size primary powders. The fine-sized precursor powders formed the fine-sized LiCoO₂ and Li(Co_0.75Ni_0.25)O₂ cathode powders by solid state reaction with LiOH powders. However, the high contents of the nickel component of the Co₃O₄/NiO precursor powders formed the Li(Co_xNi_1 − x)O₂ (0 ≤ x ≤ 0.5) cathode powders with aggregated morphologies and large sizes. The discharge capacities of the powders increased with increasing the nickel content into the Li(Co_xNi_1 − x)O₂ cathode powders up to 188 mAh/g.     

Physical properties of Mo6−xRuxTe8 and Mo6Te8−xSx

A series of the Chevrel phases, Mo_6−xRu_xTe₈ and Mo₆Te_8−xS_x (x=0, 1, 2), has been prepared and the various physical properties, such as the elastic modulus, Debye temperature, and electrical resistivity, have been evaluated. The relationships between several properties of the compounds have also been studied. Young’s modulus and Debye temperature of Mo_6−xRu_xTe₈ and Mo₆Te_8−xS_x increase with increasing x value. The relationship between the Vickers hardness and Young’s modulus shows ceramic characteristics for Mo_6−xRu_xTe₈, while they show glass-like characteristics for Mo₆Te_8−xS_x. The electrical resistivities of Mo_6−xRu_xTe₈ and Mo₆Te_8−xS_x increase with increasing x value.     

Preparation and bulk thermal expansion studies in M1−xCexSiO4 (M = Th, Zr) system, and stabilization of tetragonal ThSiO4

Two series of compositions with the general formula M_1−xCe_xSiO₄ (M = Th, Zr; x = 0.0–0.5; 1.0) were prepared by a standard solid state route and characterized by powder XRD. About 10 mol% of ceria could be dissolved in the lattice of ThSiO₄. A striking observation was the stabilization of tetragonal modification of ThSiO₄, which is metastable, by ceria substitution. There was no solubility of ceria in zircon (ZrSiO₄) lattice. The average linear thermal expansion coefficient (293–1123 K) of ZrSiO₄, ThSiO₄ and Th_0.9Ce_0.1SiO₄ are 4.65 × 10⁻⁶, 4.97 × 10⁻⁶ and 5.14 × 10⁻⁶ K⁻¹, respectively.     

Crystal fields in (La1−xGdx)OCl:Eu solid solutions

The formation of cation solid solution in the (La_1−xGd_x)OCl:Eu³⁺ (0≤x_Gd≤1; Δx_Gd=0.1) series was studied by photoluminescence spectroscopy. The luminescence from the ⁵D_0–2 to the ⁷F_0–4 levels of the Eu³⁺ ion in the (La_1−xGd_x)OCl series was recorded at 77 K by using argon ion laser excitation (457.9 nm). The interpretation of the spectra according to the C_4v site symmetry of the Eu³⁺ ion in the tetragonal PbFCl-type structure yielded nearly complete sets (18 to 19 levels) for the ⁷F_0–4 levels. Simulations of the Stark level schemes were carried out with the aid of a phenomenological c.f. theory utilizing the five non-zero c.f. B_q^k parameters (B₀², B₀⁴, B₄⁴, B₀⁶ and B₄⁶) allowed for the C_4v site symmetry. By using the calculated c.f. parameter sets a quantitative measure was obtained to monitor the formation of cation solid solutions. The strength of the c.f. effect was estimated with the c.f. strength parameters S and S^k (k=2, 4 and 6). The c.f. parameter sets reproduced the experimental ⁷F_J (J=0–4) energy level schemes with the rms deviations between 4 and 11 cm⁻¹. The individual parameters as well as the c.f. strength parameters were found to evolve in a smooth manner indicating complete solid solubility in the (La_1−xGd_x)OCl series. Some local distortions from the C_4v symmetry — probably of long range—leading to the splitting of the ⁷F₁ doubly degenerate E level were observed, however.     

Length scale and time scale effects on the plastic flow of fcc metals

We examine size scale and strain rate effects on single-crystal face-centered cubic (fcc) metals. To study yield and work hardening, we perform simple shear molecular dynamics simulations using the embedded atom method (EAM) on single-crystal nickel ranging from 100 atoms to 100 million atoms and at strain rates ranging from 10⁷ to 10¹² s⁻¹. We compare our atomistic simulation results with experimental data obtained from interfacial force microscopy (IFM), nano-indentation, micro-indentation and small-scale torsion. The data are found to scale with a geometric length scale parameter defined by the ratio of volume to surface area of the samples. The atomistic simulations reveal that dislocations nucleating at free surfaces are critical to causing micro-yield and macro-yield in pristine material. The increase of flow stress at increasing strain rates results from phonon drag, and a simple model is developed to demonstrate this effect. Another important aspect of this study reveals that plasticity as reflected by the global averaged stress–strain behavior is characterized by four different length scales: (1) below 10⁴ atoms, (2) between 10⁴ and 10⁶ atoms (2 μm), (3) between 2 μm and 300 μm, and (4) above 300 μm.     

Raman scattering study of the lattice dynamics of β-Zn4−xCdxSb3

Micro-Raman scattering experiments have been performed on the ternary solid solution in the Zn₄Sb₃–Cd₄Sb₃ system. Ten samples were studied; their compositions go from Zn₄Sb₃ to Zn_3.1Cd_0.9Sb₃. The homogeneity of these samples was checked by X-ray diffraction and electron microprobe analysis. The corresponding lattice parameters were calculated and their concentration dependence exhibits a small negative deviation from Vegard's law between end members of the Zn₄Sb₃–Cd₄Sb₃ system.

Three peaks and one shoulder are easily observable in the Raman spectrum of β-Zn₄Sb₃. These peaks are still present when the zinc atoms are substituted by cadmium ones. As the intensities of the Raman lines were observed to be very sensitive to the direction of the microcrystallites, only the change of the position could be discussed. From these experiments, we can suggest that the peak at about 155 cm⁻¹ should imply essentially Sb–Sb bondings while the peaks at about 172 cm⁻¹ and 320 cm⁻¹ must also imply Cd–Sb and Zn–Sb bondings.