Decreased Lattice Constant Research Articles

Enhanced high-rate and long-cycle performance of Mg2+-Al3+ co-doped spinel LiMn2O4 cathode materials for Li-ion batteries

Spinel LiMn2O4 has the potential to be used as a cathode material in lithium-ion batteries because of its affordability, low toxicity, and excellent charge/discharge capability. However, severe capacity attenuation results from the degradation of its long-cycle and high-rate performance caused by the Jahn-Teller distortion and Mn dissolution. Herein, a simple solid-state combustion process is used to successfully prepare the Mg2+-Al3+ co-doped LiMn2O4 with truncated octahedral morphology. The Jahn-Teller distortion is inhibited by the stable Mn-O framework and the decreased lattice constant, which in turn lowers the dissolution of Mn. Moreover, Mg2+-Al3+ co-doped LiMn2O4 have lower activation energy and greater Li+ diffusion coefficient. As a result, the optimized LiMg0.03Al0.10Mn1.87O4 delivers satisfied initial capacity of 102.1 mAh‧g−1 with a capacity retention of 76.2 % after 1000 cycles at 10 C. Even at the ultra-high rate of 15 C and 20 C, Mg2+-Al3+ co-doped sample also remain desired structure stability and cycling performance, which remains 73.8 % of its original capacity after 1000 cycles at 20 C. This work provides a reference for developing high-performance and stability cathode materials for lithium-ion battery.

Insights into the optoelectronic and thermoelectric properties of defect chalcopyrites XAl2Se4 (X = Zn, Cd, and Hg): A density functional theory approach

In the current study, we employed the full-potential linearized augmented plane wave plus local orbitals (FP-LAPW + lo) approach within the density functional theory (DFT) to investigate the physical properties of Defect Chalcopyrites XAl2Se4 (X = Zn, Cd, and Hg). Calculations yield precise structural and electronic parameters in good agreement with experimental data, revealing all three compounds as direct wide-bandgap semiconductors. The modified Becke-Johan potential (TB-mBJ) method accurately estimates energy gaps, which increase with decreasing lattice constants. The calculated values are 3.34 eV, 3.12 eV, and 2.30 eV for ZnAl2Se4, CdAl2Se4, and HgAl2Se4, respectively. The optical properties, including dielectric function and absorption coefficient, indicate potential applications in visible and ultraviolet optoelectronic devices. The high anisotropy of these materials further enhances their suitability for a range of linear and nonlinear optical applications. Moreover, ZnAl2Se4 exhibits the highest Seebeck coefficient at room temperature. The positive Seebeck coefficient confirmed the p-type behavior of the studied compounds. The highest observed power factor demonstrates optimal thermoelectric performance for these materials. High electrical conductivity values suggest their suitability as effective electrical conductors, especially at elevated temperatures. This study encourages further research into defect chalcopyrites for applications in optoelectronics and thermoelectric energy conversion.

RF magnetron sputtering of [formula omitted] thin films: Analysis of thermal annealing induced tuning of structural, optical characteristics, and energy band alignments

This correspondence showcases the deposition of ultra-wide bandgap β−Ga2O3 thin films via the utilization of RF magnetron sputtering at an elevated deposition temperature of 400 °C, followed by a comprehensive analysis of their structural, surface and optical properties using X-ray Diffraction (XRD), X-ray Photoelectron Spectroscopy (XPS), Raman, Ultraviolet–Visible Spectroscopy (UV–Vis), and Atomic Force Microscopy (AFM) at 800 °C, 900 °C, and 1000 °C annealed sample. Annealing up to 1000 °C led to a significant enhancement in the film’s crystallinity by 10%, accompanied by a remarkable decrease in dislocation density of up to 93.5%. The study also observed several key trends upon annealing, including a decreasing lattice constant from 12 to 11.97 Å, and an increase in the bandgap from 4.8 to 5.3 eV. Concurrently, crystallite size was consistently increased from 4.07 to 15.77 nm. The conduction band offset (CBO) decreased with higher annealing temperatures. Additionally, the increase in bandgap led to an enhancement in the critical electric field from 8.9 to 11.2 MV/cm. The Electron Density Mapping (EDM) results depicted a covalent bond between the atoms for different annealing processes along with the fundamental structural change in atomic coordinates and unit cell parameters, which has not been reported yet. These findings underline the remarkable material properties of β−Ga2O3 at 1000 °C temperatures. This establishes it as a compelling substitute for materials like SiC and GaN, showcasing its potential across various high-power applications due to a superior Baliga figure of merit and robust sensitivity even under elevated temperatures, positioning it as a promising candidate for optoelectronic applications.

Synthesis and Characterization of High-Entropy-Alloy-Type Layered Telluride MBi2Te4 (M = Ag, In, Sn, Pb, Bi).

Recently, high-entropy alloys (HEAs) and HEA-type compounds have been extensively studied in the fields of material science and engineering. In this article, we report on the synthesis of a layered system MBi2Te4 where the M site possesses low-, middle-, and high-entropy states. The samples with M = Pb, Ag1/3Pb1/3Bi1/3, and Ag1/5In1/5Sn1/5Pb1/5Bi1/5 were newly synthesized and the crystal structure was examined by synchrotron X-ray diffraction and Rietveld refinement. We found that the M-Te2 distance was systematically compressed with decreasing lattice constants, where the configurational entropy of mixing at the M site is also systematically increased. The details of structural refinements and the electrical transport property are presented.

Epitaxial growth and electronic properties of an antiferromagnetic semiconducting VI2 monolayer.

The van der Waals materials down to the monolayer (ML) limit provide a fertile platform for exploring low-dimensional magnetism and developing the novel applications of spintronics. Among them, due to the absence of the net magnetic moment, antiferromagnetic (AFM) materials have received much less attention than ferromagnetic ones. Here, by combining scanning tunneling microscopy and state-of-the-art first-principles calculations, we investigate the preparation, and electronic and magnetic properties of a vanadium(II) iodide (VI2) ML. Single-layer VI2 has been grown by molecular beam epitaxy on Au(111) surfaces. A band gap of 2.8 eV is revealed, indicating the semiconducting nature of the VI2 ML. Vanadium and iodine vacancy defects give rise to additional feature states within the bandgap. A typical 120° AFM spin ordering is maintained in the ML limit of VI2, as revealed by the first-principles calculations. Besides, the AFM coupling is greatly enhanced by slightly decreasing lattice constants. Our work provides an ideal platform for further studying two-dimensional magnetism with non-collinear AFM ordering and for investigating the possibility of realizing the spin Hall effect in the ML limit.

Improved tribological behavior of plasma-nitrided AlCrTiV and AlCrTiVSi high-entropy alloy films

Plasma nitriding was used to improve the tribological properties of AlCrTiV and AlCrTiVSi high-entropy alloy (HEA) films. The results indicated that after plasma nitriding, the microstructure and tribological property were improved greatly. For plasma-nitrided AlCrTiV, it is still composed of a single BCC solid solution but with a decreased lattice constant, while for plasma-nitrided AlCrTiVSi, a new V4.75Si3N0.58 nitride phase forms in the amorphous matrix, which all lead to the increase of nano-hardness, promoting the reduction of wear degree or wear rate against GCr15 and Al2O3. Due to the perfect balance of hardness and toughness, the plasma-nitrided AlCrTiV HEA film has the lowest friction coefficient (against Al2O3) and the best wear-resistance.

Highly epitaxial YBa2Cu3O7−δ films grown on gradient La2−x Gd x Zr2O7-buffered NiW-RABiTS using all sol–gel process

The overall purpose of this work is to develop a reliable and low-cost technique for fabrication of coated conductors (CCs) on the flexible substrates, and to understand the effects of oriented growth and microstructure on the superconducting performance of CCs in-depth. The investigations of gradient La2−x Gd x Zr2O7 buffer architecture and YBa2Cu3O7−δ (YBCO) film on Ni-5at%W rolling-assisted biaxially textured substrate using all sol–gel process are reported. Combining x-ray diffraction and transmission electron microscopy (TEM) analysis, it is revealed that the gradient buffer architecture with increased lattice constant along the direction of film growth has an excellent c-axis orientation, while the inversed gradient architecture with decreased lattice constant shows the deteriorated orientation, indicating that the highly epitaxial growth mechanism most likely related to the interfacial lattice matching degree. The detailed analysis of YBCO films grown on gradient La2−x Gd x Zr2O7 under different deposition parameters, and the influence of microstructure on electrical properties are systematically discussed using x-ray diffraction, rocking curve test, scanning electron microscopy and TEM observations. Finally, the excellent biaxial texture YBCO film on gradient La2−x Gd x Zr2O7 buffer architecture is prepared at a proper heat-treatment temperature of 780 °C, and the full width at half maximum of ϕ-scan and ω-scan are 5.9° and 6.4°, respectively. The critical transition temperature T c,onset of the as-prepared YBCO film is 90 K. With elevating the temperatures, the appearance of a large number of weak-link and amorphous regions, being indicative of the microstructural collapse, is mainly responsible for the reduced superconductivity.

Structural, elastic, electronic, and magnetic properties of Si-doped Co2MnGe full-Heusler type compounds

The structural, electronic, magnetic and elastic properties of Co2MnGe1-xSix (x = 0, 0.25, 0.50, 0.75, and 1) compounds are investigated by first-principles calculations within the generalized gradient approximation (GGA). The calculated structural parameters of these compounds show a slightly decreasing lattice constants and similarly decreasing lattice volumes and enthalpies of formation on increasing Si substitution x. The band structure calculations estimate that these compounds at their optimized lattice constants are half-metallic ferromagnets. The calculated total magnetic moment values are all integers, which is typical for half-metallic materials with a half-metallic bandgap (EHM) in the minority states. Besides, the total magnetic moments of these compounds are fully compatible with the Slater-Pauling rule showing the half-metallicity and large spin polarization desired for spintronics applications. The partial substitution of the Ge atom by the Si does not affect the atomic magnetic moment and total magnetic moment. The obtained values of structural parameters, total and atomic magnetic moments for x = 0 and 1 stoichiometric compounds are in good agreement with experimental and theoretical results. The elastic constants are studied for all compositions of x in order to verify the mechanical stability of these compounds. Born’s stability criterion implemented on elastic constants of Co2MnGe1-xSix (x = 0, 0.25, 0.50, 0.75, and 1) compounds confirm that these materials are mechanically stable. Other elastic parameters like bulk modulus (B), shear modulus (G), ratio of B/G, Young’s modulus (E), Poisson’s ratio (ν), and Shear anisotropic factor (A), which are the significant elastic moduli for technological applications have been thoroughly investigated. Consequently, these compounds, especially Co2MnGe1-xSix (x = 0.25, 0.50, 0.75) mixed systems, are promising candidates for practical applications in the field of spin electronics.

Synthesis and Characterization of Structural, and Electrical Properties of Mg(0.25x)Cu(0.25x)Zn(1 – 5x)Fe2O4 Ferrites by Sol-Gel Method

The effects of magnesium, copper, and zinc substitutions on spinel ferrites have been investigated by the sol-gel technique. Ferrite compositions of Mg0,25xCu0,25xZn(1−0,5x)Fe2O4 (where x = 0.6, 0.7, 0.8 & 0.9) were prepared at a sintering temperature of 1100 ∘C with a presintering at 500 ∘C. X-ray diffraction (XRD), scanning electron microscopy (SEM), and high-precision impedance analysis are used to characterize structural and dielectric properties, as well as the surface topography and morphology of the samples. A single phase, cubic spinel structure, with decreased lattice constant was observed. SEM micrographs revealed a homogeneous microstructure with uniform size distributions. Both the dielectric constant and dielectric loss tangent decrease, as the incident frequency increases up to a certain saturation point. The direct current (dc) resistivity profile shows that the resistivity increases with the temperature up to the Curie point, then it goes to a constant value. The quality factor (Q-factor) increases with the incident frequency. Hence, the high Q-factor will make ferrites highly useful in applications, especially in multilayer chip inductors.

The analyses of structure and luminescence in (MgyY3-y) (Al5-ySiy)O12 and Y3(MgxAl5-2xSix)O12 ceramic phosphors

In this paper, the chemical composition of Y3Al5O12 was modified to Ce:(MgyY2.99-y) (Al5-ySiy)O12 (MYASG) and Ce:Y2.99(MgxAl5-2xSix)O12 (YMASG) through the Mg2+-Si4+ substitution for Y3+-Al3+ and Al3+-Al3+, respectively. The increasing (decreasing) lattice constants, downward (upward) shift of Raman peaks and shorter (longer) luminescence lifetime were investigated in YMASG (MYASG) through the Rietveld analysis, Raman spectra and luminescent decay spectra. Moreover, a massive red-shift emission peak was observed in YMASG, from 537 nm to 577 nm. While for MYASG, the maximum emission peak of Ce3+ locates at 552 nm and the emission peaks remain unchanged even further increasing Mg2+-Si4+. The distinct red-shift properties can be ascribed to the different crystal structure due to the Mg2+ doping in different coordinate sites and are clarified by the configuration coordinate model. The broad color area from yellow to orange region in the color coordinates diagram was achieved which proves the great potential application of YMASG ceramic phosphors in the warm white light illumination.

Platinum overlayers on PtxRu1−x(111) electrodes: Tailoring the ORR activity by lateral strain and ligand effects

A systematic electrochemical study of pseudomorphic Pt(111) thin films is presented. Well-defined Pt-rich surfaces are obtained by inductive heating of bulk PtxRu1−x(111) single crystals (x=0.1–1) and cooling in an inert gas atmosphere, taking advantage of the segregation behavior of Pt. Due to the difference in atomic diameters of Pt and Ru, compression of the Pt-rich surfaces can be achieved as a function of Pt mole fraction in the bulk alloy single crystal. The electrochemical behavior of characteristic adsorption processes is evaluated by cyclic voltammetry for the samples in contact with 0.1M HClO4 and 0.1M H2SO4. Adsorbed hydrogen (Had), OHad/Oad and (bi)sulfate are found to be more weakly adsorbed with decreasing lattice constant of the Pt(111) surface. A volcano-shaped dependence of the ORR activity on lateral compression of the Pt surface could be established in the potential region of low overpotentials (0.95–1.05V). For 0.1M HClO4, the highest overall ORR-activity was measured for Pt on Pt0.7Ru0.3(111), exceeding that of pristine Pt(111) distinctly, whereas for 0.1 H2SO4 the highest activity was found for Pt0,9Ru0,1(111). Consequently, the electrochemical and the electrocatalytic behavior is strongly dependent on the electrolyte composition, pointing towards an influence of (bi)sulfate adsorption beyond the site-blocking mechanism commonly referred to. Specific adsorption of spectator-species plays a key role for oxygen reduction reaction kinetics. Such correlations between surface electronic structure and reactivity are of major relevance for tailoring the adsorption properties of electro-catalysts, considering both strain and electronic ligand effects.

Self assembly of three-dimensional Lu2O3:Eu3+ inverse opal photonic crystals, their modified emissions and dual-functional refractive index sensing

In this study, Lu2O3:Eu(3+) inverse-opal-photonic crystals (IOPCs) with controllable lattice constants were fabricated using a polymethylmethacrylate (PMMA) template. The modification effect of PC on the (5)D0-(7)F(J) and (5)D1-(7)F(J) (J = 1-6) transitions were systemically studied by emission spectra, luminescent dynamics and the temperature-dependence. It is significant to observe that the increase of (5)D0-(7)F(J) radiative lifetime for Eu(3+) ions (30%) in contrast to the reference sample was mainly due to modulation of the effective refractive index, rather than the density of optical states. The spontaneous decay rate in (5)D1 increased linearly with the decreasing lattice constants, which was due to the change in (5)D1-(5)D0 nonradiative relaxation of the IOPC samples. The temperature quenching of Eu(3+) ions in the IOPCs could be suppressed considerably more than the reference. On this basis, dual functional refractive index detection with infiltrated solutions was realized by monitoring the variation in the photonic stop band (PSB) and the lifetime of (5)D0-(7)F2 transition of the Lu2O3:Eu(3+) IOPCs. This work shows that the Lu2O3:Eu(3+) IOPCs present highly modified photoluminescence properties and are promising candidates for dual-functional refractive index sensing application.

Effects of Alloying Elements on the Oxygen Snoek-Type Relaxation in Ti-Nb Alloys

The effect of ternary alloying elements on the oxygen Snoek-type relaxation in the Ti-24Nb-2X-1.7O alloys (X = Al, Sn, Cr, Mn, Fe) was investigated. The dipole shape factor (δλ) of the Snoek-type relaxation was figured out for each ternary alloy based on the measured damping peak with the variable temperature. The value ofδλin the Ti-Nb-Al alloy was the highest among the present ternary alloys. It was found thatδλincreased with the decreasing lattice constant as well as the decreasing valence electron number per atom (e/a) and came to a maximum value when the e/a value was around 4.24, which defined the β phase boundary. Therefore, decreasing the lattice constants and the e/a value as largely as possible with alloying elements in the β-Ti alloys is one of the feasible ways to increaseδλand to design the high damping Ti alloys.

Effects of the Ta content on the microstructure and electrical property of reactively sputtered Ta xZr 1−xN thin films

The Ta xZr 1−xN films were prepared by reactive magnetron sputtering and the concentration of zirconium and tantalum was regulated by controlling the power to the sputtering guns. The effects of the Ta content on the microstructure, composition and electrical properties of Ta xZr 1−xN films were investigated by x-ray diffraction, field-emission electron probe micro-analyzer, atomic force microscopy, x-ray photoelectron spectroscopy, four point probe and Hall-effect measurements. Results indicated that the Ta xZr 1−xN films with different Ta contents were crystallized in NaCl-type structure. However, the lattice constant of Ta xZr 1−xN films decreased with the increase of the Ta content due to the smaller ionic radius of Ta 5+ comparing with that of Zr 4+. The decreasing lattice constant of Ta xZr 1−xN films with the Ta content evidenced the successful substitution of Zr with Ta. The electrical resistivity of Ta xZr 1−xN films showed a minimum value of 78 μΩ cm at Ta content of 3.5 at.% and then increased with the increase of Ta content. Hall measurements indicated that the electrical conduction of films was essentially due to electrons (n-type). And the increase of carrier density and mobility at a Ta content of 3.5 at.%, caused by the extra d valence electron of Ta and the less electron scattering of grain boundaries, was responsible for the further decreasing of resistivity from pure ZrN x films.

A highly active PtNi/C electrocatalyst for methanol electro-oxidation in alkaline media

A carbon supported PtNi/C electrocatalyst synthesized via a polyol process was characterized by XRD, TEM and voltammetry techniques. The XRD analysis showed a decreased lattice constant of Pt for the PtNi/C catalyst compared with the Pt/C. indicating partial PtNi alloy formed. The PtNi/C exhibited enhanced mass activity towards methanol oxidation reaction as well as decreased CO stripping currents in alkaline media compared with the Pt/C. Density functional theory studies revealed the electronic structure modification of Pt by Ni atoms and weakened CO adsorption energy on the Pt(3)Ni than on the Pt(4) clusters, which may account for the increased MOR activity. Crown Copyright (C) 2010 Published by Elsevier By. All rights reserved.

Enhanced Dielectric Response in Mg-doped CaCu 3Ti 4O 12 Ceramics

CaCu 3 Ti 4 O 12 ceramics substituted by Mg for Ca were prepared by the solid state reaction method. The crystal structures, microstructures, and dielectric properties of the Ca 1- x Mg x Cu 3 Ti 4 O 12 ceramics were investigated. At lower doping concentrations, the substitution of Mg for Ca caused a decreased lattice constant, while at higher doping concentrations, some of the Mg dopants started to replace Ti and resulted in an increased lattice constant, and some could also replace Cu due to the similar ion radius between Mg and Cu ions. Mg doping was found to promote the grain growth of Ca 1- x Mg x Cu 3 Ti 4 O 12 ceramics during sintering. Grain boundary resistance of the Ca 1- x Mg x Cu 3 Ti 4 O 12 ceramics was found to be increased by Mg doping. Enhanced dielectric properties was observed in the Ca 1- x Mg x Cu 3 Ti 4 O 12 ceramics with x =0.05 for the frequency range from 1 kHz to 20 kHz. For other doping concentrations, the dielectric losses of Ca 1- x Mg x Cu 3 Ti 4 O 12 ceramics were generally lowered.

Phonons in Lattice and Structural Dynamics

The critical temperature () of superconductivity in compounds is generally lower smaller with alkali atoms (A). Furthermore decreases with applied pressure. In the BCS model, these trends are explained by the lower density of states at the Fermi level for a decreased lattice constant (R). There is more than one counterexample, however, suggesting that BCS does not give the whole truth. The most important one is that the compound with the largest lattice constant, , is not superconducting at all at ambient pressure. In this paper we derive a novel model where a negative lattice contribution to HubbardU, proportional to1/R, is taken into account. It is possible to explain why compounds with A = Li, and Na have a low or are not superconducting at all, and why is superconducting only at applied pressure and then with the highest of all alkali fullerides. It is concluded that the density of states mechanism derived in the BCS model is in doubt. Nevertheless superconductivity in depends on electron-phonon coupling. The dominating phonon is the bond stretching phonon, a breathing phonon for the whole fullerene molecular ion.

M3NS3 (M = La – Nd, Sm, Gd – Dy): Struktur und Magnetismus von 3:1:3‐Typ‐Nitridsulfiden dreiwertiger Lanthanide

AbstractM3NS3 (M = La – Nd, Sm, Gd – Dy): Structure and Magnetism of 3:1:3‐Type Nitride Sulfides of Trivalent LanthanidesNitride sulfides of the trivalent lanthanides with the composition M3NS3 (M = La – Nd, Sm, Gd – Dy) can be prepared by the oxidation of the respective lanthanide metal with sulfur, sodium azide (NaN3), and the corresponding lanthanide tribromide (MBr3) when an additional flux (NaBr) is used. Temperature ranges from 800 to 900 °C for the thermal treatment of the reaction mixtures in evacuated silica tubes secure the formation of bright to dark brown, transparent, lath shaped single‐crystals. The orthorhombic crystal structure (Pnma, Z = 4) was determined from single‐crystal X‐ray diffraction data (La3NS3: a = 1215.13(5), b = 415.90(2), c = 1322.12(5) pm, Ce3NS3: a = 1206.28(4), b = 410.16(1), c = 1307.18(5) pm, Pr3NS3: a = 1205.45(7), b = 405.35(2), c = 1297.58(8) pm, Nd3NS3: a = 1207.82(5), b = 401.31(1), c = 1295.20(4) pm, Sm3NS3: a = 1201.58(6), b = 394.84(2), c = 1285.63(7) pm, Gd3NS3: a = 1197.17(7), b = 388.22(3), c = 1286.92(8) pm, Tb3NS3: a = 1191.62(7), b = 385.07(3), c = 1282.44(8) pm, and Dy3NS3: a = 1187.66(7), b = 382.55(3), c = 1276.77(8) pm). There are three crystallographically different M3+ cations present in coordination of both the N3− and the S2− anions. However, [NM4]9+ tetrahedra connected via two common corners (c) to form linear chains $^{1}_{\infty}\rm \{[N(M1)^{t}_{1/1}(M2)^{t}_{1/1}(M3)^{c}_{2/2}]^{6+}\}$ along [010] build up the main structural feature. A non‐linear behaviour for the decreasing lattice constants of the pseudo‐isotypic series from La3NS3 to Dy3NS3 concerning the a‐ and c‐axes is observed along with the lanthanoid contraction caused by the diminishing coordination sphere of (M1)3+ (CN = 7) and (M3)3+ (CN = 7) moving from the light to the heavier lanthanides. Curie‐Weiss‐type magnetic behaviour for Dy3NS3 with μeff = 10.3(1) μB for DyN1/3S corresponding to a 6H15/2 groundstate for Dy3+ at higher temperatures and antiferromagnetic ordering of the Dy3+ moments below 5 K is observed.

Deep ultraviolet photoluminescence studies of AlN photonic crystals

Two-dimensional AlN photonic crystals (PCs) with varying periodicity/diameter down to 150∕75nm were fabricated. Deep ultraviolet photoluminescence spectroscopy has been employed to study the optical properties of AlN PCs. With PC formation, a 20-fold enhancement in the band edge emission intensity at 208nm over unpatterned AlN epilayer has been observed. The emission intensity increases with decreasing lattice constant of AlN PCs. However, the spectral peak energy decreases with decreasing lattice constant, indicating a possible release of compressive stresses as a result of PC formation. Successful fabrication of AlN PCs opens up new opportunities for exploring novel physical phenomena in the artificially structured photonic band gap material system and their applications, particularly in the area of deep UV photonics.

Pressure induced phase transition in rare earth mono-antimonides

Pressure induced structural phase transition of mono-antimonides of lanthanum, cerium, praseodymium and neodymium (LnSb, Ln=La, Ce, Pr and Nd) has been studied theoretically using an inter-ionic potential with modified ionic charge which parametrically includes the effect of Coulomb screening by the delocalized f electrons of rare earth (RE) ion. The anomalous structural properties of these compounds have been interpreted in terms of the hybridization of f electrons with the conduction band and strong mixing of f states of Ln ion with the p orbital of neighbouring antimonide ion. All the four compounds are found to undergo from their initial NaCl (B 1) phase to body centered tetragonal (BCT) phase at high pressure and agree well with the experimental results. The body centered tetragonal phase is viewed as distorted CsCl structure and is highly anisotropic with c/ a=0.82. The transition pressure of LnSb compounds is observed to increase with decreasing lattice constant in NaCl phase. The nature of bonds between the ions is predicted by simulating the ion-ion (Ln–Ln and Ln–Sb) distances at high pressure. The calculated values of elastic constants are also reported.