Variation Of Unit Cell Parameters Research Articles

Scanning Precession Electron Tomography (SPET) for Structural Analysis of Thin Films along Their Thickness

Accurate structure analysis of epitaxial perovskite thin films is a fundamental step towards the ability to tune their physical properties as desired. Precession-assisted electron diffraction tomography (PEDT) has proven to be an effective technique for performing ab initio structure solutions and refinements for this class of materials. As the film thickness or the region of interest (ROI) decrease in size, the capacity to collect PEDT data with smaller electron beams is a key parameter and ROI tracking becomes a major issue. To circumvent this problem, we considered here an alternative approach to acquiring data by combining PEDT with a scan over an area, extracting the intensities collected at different positions and using them to perform accurate structure refinements. As a proof of concept, a Scanning Precession Electron Tomography (SPET) experiment is performed on a 35 nm thick perovskite PrVO3(PVO) film deposited on a SrTiO3 (STO) substrate. This way, it was possible to detect small changes in the PVO structure along the film thickness, from the variation in unit cell parameters to atomic positions. We believe that SPET has the potential to become the standard procedure for the accurate structure analysis of ROIs as small as 10 nm.

Correlation of structure and dielectric response in Ce-doped double perovskite cobaltite

Double perovskite Bi2Ca2-xCexCoO6; x = 0.00, 0.05, 0.10 and 0.15 (BCCCO) is synthesized by co-precipitation route. X-ray diffraction (XRD) confirms the monoclinic single-phase crystal structure with negligible variation in unit cell parameters, indicating that the Cerium (Ce) has been successfully incorporated. With Ce doping, the average crystallite size of Bi2Ca2CoO6 (BCCO) nanoparticles decreases. Scherrer's formula was used to determine the crystallite sizes (33–37 nm) of BCCO nanoparticles. Jonscher's power law is used to investigate the conduction mechanism of all the prepared specimens. The power-law specifies the correlated barrier hopping for BCCCO x = 0.00 and 0.05, short polaron tunneling for x = 0.10, while BCCCO x = 0.15 follows overlapping large polaron tunneling. The dielectric permittivity has been calculated with a frequency range of 20 Hz - 3 MHz, and the Ce doped samples show a high value of dielectric permittivity εr = 1.79 × 105 at 500 °C. The influence of crystallite size on the dielectric permittivity of BCCCO was examined in this work. The relaxation time and spreading factor of all samples are investigated using Non-linear Debye's function. All these features are studied as a function of frequency at temperatures ranging from 100 to 500 °C. Here, the DC electrical conductivity of BCCCO is investigated by the four-probe method at 50–400 °C. In Ce-doped specimen the lowest value of thermal conductivity (k = 0.797 W/m-K at 120 °C) has been observed.

Study of The Electrical, Optical and Morphological Properties in Submicron and Microstructured ZnO Thin Films Obtained by Spin Coating and Chemical Bath Deposition

In the present work the synthesis of ZnO semiconductor thin films was performed successively using spin coating and chemical bath deposition techniques. The deposition was made by varying the concentration of zinc acetate and hexamethylenetetramine (HMTA: ZnAc) in the precursor solution. This process led to two preferred growth directions (002) and (101), both with very similar texture coefficients, too; a noticeable change in morphology of structured surface, variation in unit cell parameters and crystalline grain size. All the films turned out homogeneously submicro and microstructured and with a wurtzite-type hexagonal crystalline structure. Using pre-loaded Mathematica 11.3 software functions and an algorithm developed in it, the micrographies were analyzed to calculate the percentage of substrate-covered area which was always greater than 80%. Likewise, it also found that resistivity decreases at a higher percentage of covered area and that the variation in the shape of the photo luminescent emission spectrum can be considered as a qualitative indication of the concentration of charge carriers.

Ceramic pigments from CoxNi3-xP2O8 (0 ≤ x ≤ 3) solid solutions

CoxNi3-xP2O8 (0 ≤ x ≤ 3) solid solutions were synthesized via the chemical co-precipitation method. Variation of unit cell parameters and interatomic distances indicated that these solid solutions with the Ni3P2O8 structure are stable between 800 and 1200 °C in compositions with 0 ≤ x ≤ 1.5 and between 800 and 1000 °C when (0 ≤ x ≤ 3). When (2.5 ≤ x ≤ 3.0), the solid solutions lead to the Co3P2O8 structure, being stable between 800 and 1000 °C.The yellow colour of the Ni3P2O8 compound changes to pink or red when Co(II) ions are incorporated in the structure as Ni3P2O8 solid solutions are formed. Bands corresponding to second and third electronic transitions of the Co(II) ions in octahedral coordination appear in the 450–600 nm in the UV-V spectra, and they are responsible of the observed changes in the colour. Absorbance in the visible spectra was also obtained from enamelled samples but a new band at 650 nm with considerable absorbance when x > 1.0 increased the blue amount, and colour of the enamelled samples was yellowish brown, brown, green and blue.

Phase equilibria and oxygen content of intermediate phases in the Sm2O3–SrO–Fe2O3 system

Six types of oxide phases are formed in the Sm2O3–SrO–Fe2O3 system at 1100 °C in air: perovskite type Sr1-хSmхFeO3-δ (0.05 ≤ х ≤ 0.50 with the cubic structure, S.G. Pm-3m and 0.85 ≤ x ≤ 1.0 with the orthorhombic structure, S.G. Pbnm), and Ruddlesden-Popper series corresponding to n = 1,2,3, i.e. Sr2-ySmyFeO4-δ, Sr3-uSmuFe2O7-δ (0 ≤ u ≤ 0.3; u = 1.80) and Sr4-rSmrFe3O10-δ. The structural parameters of single-phase samples, refined by the Rietveld method, allowed to reveal the variation of unit cell parameters with composition. A subsolidus isothermal isobaric phase diagram (1100 °C, Po2 = 0.21 atm) for the ½Sm2O3–SrO–½Fe2O3 system has been constructed. The compositional triangle was divided into 24 phase fields. The values of oxygen content and mean oxidation state of iron in all single phases were determined by iodometric titration. The changes in oxygen content with temperature in Sr2.7Sm0.3Fe2O7-δ, Sr1.2Sm0.8FeO4-δ, and Sr3.1Sm0.9Fe3O10-δ were studied by TGA within the range of 25−1100 °C in air. They show that the maximum oxidation state of Fe ions in RP oxides at room temperature increases with n, reaching 3.52 for the Sr3.1Sm0.9Fe3O10-δn = 3 member.

Growth and characterization of lithium chloride doped KDP crystals: a DFT and experimental approach

The potassium dihydrogen phosphate (KDP) is a popular nonlinear optical material. Optically good quality LiCl doped KDP crystals have been grown by slow solvent evaporation method at room temperature. The structural study of grown crystals reveled single phasic nature of grown crystals with slight variation in unit cell parameters. I had done the Rietveld refinement to study the influence of dopant in the structure of KDP. The linear optical properties of grown crystals such as optical transparency energy band gap, reflectance, extinction coefficient, refractive index, etc. were studies using the UV-Visible spectroscopy. The Kurtz and Perry powder NLO technique was employed to study the nonlinear optical improvement in KDP crystal due to doping. The AC electrical study of grown crystals was done using the complex impedance spectroscopy. The theoretical study of grown crystals has been done using the Generalized Gradient Approximation pseudopotential method. The results are discussed here.

Hydrogen storage in AB2 hydride alloys: Diffusion processes analysis

AB2 alloys have been extensively studied as Ni-MH battery anodes. In the hydriding process, hydrogen diffusion inside the crystal lattice is the determining step, so a comparison between gas phase and electrochemical environment was carried out. As concern, we have found structural changes as a consequence of hydriding in terms of segregation of different stable phases and variations in unit cell parameters in each alloy. Maximum hydrogen storage capacity and hydrogen molar volume for studied alloys were evaluated by PCT curves at different temperatures. Resulting values were compared with electrochemical PCT (ECT plots). Results obtained for both methods were similar, with a hydrogen molar volume value close to 30 cm3 mol−1 being higher for AB2M0 in accordance with the reported capacity values. Diffusion time constants were determined from GITT, achieved data were similar to previously reported by EIS and HRD. AB2M1 alloy showed the best kinetic behavior, depicting a time constant value an order of magnitude lower than AB2M0. This fact could be attributed to the diffusion coefficient and/or the hydrogen diffusion length mean path. No significant differences in thermodynamic parameters were observed between both alloys, therefore, the diffusion coefficients should be similar. Thus, differences in time diffusion constants were attributed to dissimilar mean lattice diffusion paths associated with changes in crystalline structures as a result of the hydriding process.

Determining phase transitions of layered oxides via electrochemical and crystallographic analysis

ABSTRACT The chemical diffusion coefficient in LiNi1/3Mn1/3Co1/3O2 was determined via the galvanostatic intermittent titration technique in the voltage range 3 to 4.2 V. Calculated diffusion coefficients in these layered oxide cathodes during charging and discharging reach a minimum at the open-circuit voltage of 3.8 V and 3.7 V vs. Li/Li+, respectively. The observed minima of the chemical diffusion coefficients indicate a phase transition in this voltage range. The unit cell parameters of LiNi1/3Mn1/3Co1/3O2 cathodes were determined at different lithiation states using ex situ crystallographic analysis. It was shown that the unit cell parameter variation correlates well with the observed values for chemical diffusion in NMC cathodes; with a notable change in absolute values in the same voltage range. We relate the observed variation in unit cell parameters to the nickel conversion into the trivalent state, which is Jahn-Teller active, and to the re-arrangement of lithium ions and vacancies.

Third Order Non Linear Material of L-Threonine Dihydrogen Phosphate Crystals

The L-Threonine dihydrogen phosphate crystals are grown using conventional slow evaporation technique. Single crystal X-ray diffraction studies justify the incorporation of Phosphorus in crystal by variation in unit cell parameters. Field emission scanning electron microscope (FESEM), Energy Dispersive X-ray Analyses (EDAX), and Inductive coupled plasma optical emission spectroscopy provide substantial evidence for the presence of phosphorous and in the crystal. The Second Harmonic Generation (SHG) of the grown crystal is validated using Kurtz-Perry powder technique. The influence of magnesium chloride on nonlinear optical properties (NLO) is investigated using the Third order NLO behaviour by Z-scan method.

Third order non linear material of zinc sulphate doped L-Threonine dihydrogen phosphate single crystal

The Zinc sulphate doped L-Threonine dihydrogen phosphate crystals are grown using conventional slow evaporation technique. Single crystal X-ray diffraction studies justify the incorporation of zinc sulphate in crystal by variation in unit cell parameters. Field emission scanning electron microscope (FESEM), Energy Dispersive X-ray Analyses (EDAX) and Inductive coupled plasma optical emission spectroscopy provide substantial evidence for the presence of phosphorous and zinc in the crystal. The Second Harmonic Generation (SHG) of the grown crystal is validated using Kurtz-Perry powder technique. The influence of zinc sulphate on nonlinear optical properties (NLO) is investigated using the Third order NLO behavior, Z-scan method.

Structural factors affecting the crystal-chemical variability in Al-rich K-dioctahedral 2M1 micas

AbstractTo reveal the factors that determine the different ranges of compositional variations in high- and low-temperature Al-rich K-dioctahedral micas, relationships between structural parameters and cation composition were analysed for: (1) a series of synthetic 2M1 muscovite–phengite–aluminoceladonite samples; and (2) Al-rich, K-dioctahedral 2M1 micas with previously published refined structural data. The dependences of the unit-cell parameters on cation composition and the variations in tetrahedral and octahedral lateral dimensions and sheet thicknesses, interlayer distances and tetrahedral rotation angles were analysed and compared with those found previously for the series 1M trans-vacant (tv) illite–1M aluminoceladonite. The similarities in the variations of unit-cell parameters with cation composition observed in 2M1 and 1M natural and synthetic K-dioctahedral micas imply that these variations are controlled by similar – albeit not identical – structural factors. A major structural factor is the readjustment of the differently sized tetrahedral and octahedral sheets, which is realized in a different manner in micas formed under different pressure and temperature conditions.

Temperature dependent structural studies and phase transition behavior of K2Th(PO4)2

Herein we report the details of crystal structure and phase transition behavior of a complex phosphate, K2Th(PO4)2 as observed from the variable temperature powder x-ray diffraction (XRD) and neutron diffraction (PND) studies. The ambient temperature monoclinic (P21/n) structure was observed to remain unchanged down to 6 K, while above 973 K, it transforms to a tetragonal (I41/amd) structure. This structural transition occurs with a volume discontinuity of about 13.4% and reverts back to monoclinic structure on cooling but with a large hysteresis in temperature (∼100 K). From the variation of unit cell parameters and structural differences as well as differential thermal analyses studies, the transition is concluded as a first order reconstructive type. The unit cell parameters of both structures gradually increases with increasing temperature but the coefficient of thermal expansion decreases appreciably after the transition (monoclinic, αV = 49.9 × 10−6/K in between 6 and 973 K; tetragonal, αV = 33.6 × 10−6/K, in between 673 and 1173 K). The details of crystal chemistry, phase transition and thermal expansion behaviors of K2Th(PO4)2 are explained, and compared with other isostructural compositions.

Structural and magnetic properties of YAl3(BO3)4 and EuAl3(BO3)4 single crystals doped with Co2+

Structural and magnetic properties of the cobalt-doped YAl3(BO3)4 and EuAl3(BO3)4 crystals were studied using electron paramagnetic resonance (EPR), nuclear magnetic resonance (NMR), X-ray diffraction analysis, and specific heat methods.It was found that cobalt, when doped to the studied crystals, is in divalent state, substitutes the aluminum ions and forms a system of three magnetically equivalent magnetically nonequivalent centers whose magnetic axes are rotated at 120° relative to one another.We have determined parameters of the spin Hamiltonian of orthorhombic symmetry, describing the anisotropic angular dependence EPR spectra for both types of crystals. Strong broadening of EPR lines is caused by the spin-lattice relaxation.Specific heat of the EuAl3(BO3)4 and YAl3(BO3)4 crystals doped with 0.2% of Co2+ was measured over the temperature range from 3 to 395 K, in zero magnetic field. The Debye temperature was determined to be equal to 355К and 358 K for YAl3(BO3)4 and EuAl3(BO3)4, respectively. Crystallographic structure at ambient conditions as well as variations of unit-cell parameters and thermal expansion coefficients with temperature were studied in detail in the range 302 K < T < 1073 K. NMR study on 27Al and 11B nuclei at room temperature was conducted. It is shown that on changing the rare-earth ion from yttrium to europium, the contribution of hyperfine interactions to the resonance characteristics of the samples increases. It is also shown that there are two nonequivalent environments of boron atoms with an attitude close to 1.1 and 1.2 for the samples containing 0.1 and 0.2% of cobalt ions, respectively.

The relationship between Mn oxidation state and structure in triclinic and hexagonal birnessites

Because of their nanocrystallinity and high cation exchange capacities, birnessite phases can control the cycling of heavy metals in soils and groundwaters, and they also are implicated in the oxidation of transition metals in natural environments. Birnessite reactivity is determined by crystal structure and composition. Because birnessites typically are poorly crystalline, synchrotron-based absorption spectroscopy (EXAFS, XANES) often is utilized for structural characterization. For example, linear combination fitting (LCF) of X-ray absorption spectra typically is applied to quantify mixed triclinic and hexagonal birnessite phases. This approach is challenged, however, because the structures of the standards are not always plainly apparent. Moreover, it is difficult to distinguish birnessites with nanoscale intergrowths of hexagonal and triclinic endmembers from homogeneous birnessite structures of “intermediate triclinicity”.We explored these issues by synthesizing a host of cation-exchanged birnessite specimens whose long-range symmetrical character could be determined by X-ray diffraction without ambiguity. Through a combination of Fourier transform infrared spectroscopy (FTIR), extended X-ray absorption fine structure (EXAFS), and X-ray photoelectron spectroscopy (XPS), we have examined the relationships among structural symmetry, Mn oxidation state, and interlayer composition. Our results confirm prior models that as the concentration of Mn3+ increases, the departure from hexagonal symmetry also increases. Rietveld refinements indicate that the Jahn-Teller distortions associated with Mn3+ induce systematic variations in unit-cell parameters, particularly an increase in the a-axis and the β angle of the unit cell. Interlayer cation composition also controls structural distortions, and Ca-rich birnessites showed less deviation from hexagonality than did Na-, K-, and Ba-birnessites. Our linear combination fits of X-ray absorption spectra sometimes yielded misleading results, reinforcing the difficulty and importance of selecting appropriate standards.

Substitution of sulfate in apatite

The substitution of sulfate in apatite is of potential importance in synthetic biomaterials used in bone repair and reconstruction. The counter ion (e.g., Na + , K + , Mg 2+ , Sr 2+ ) in the sulfate reagent may also be used as a source of medically beneficial ions. An understanding of the structural parameters controlling sulfate substitution is also important in expanding our knowledge beyond the substitution of carbonate in apatites. The incorporation of sulfate in calcium and strontium hydroxylapatites, prepared in aqueous solution at pH 9, was verified by combustion analysis of sulfate, infrared and Raman spectroscopy, and by determination of unit-cell parameters. Sulfate could not be incorporated into barium hydroxylapatite because of the preferential formation of BaSO 4 . The amount of sulfate substituted in the apatite was affected by the mole ratio of sulfate to phosphate in the reaction mixture and by the nature of the counter ion in the sulfate reagent. When sodium is the counter ion in the sulfate reagent, the molar amounts of both sodium and sulfate in the product apatite can be explained by assuming charge compensation by sodium ions and sulfate displacement of phosphate and calcium. With lithium as the counter ion, a greater molar amount of lithium than sulfate is incorporated into the apatite, an observation that requires an additional charge-compensation mechanism. With potassium and rubidium as counter ions, less of the counter ion is incorporated than sulfate, probably a result of less favorable accommodation of the larger cation in the apatite structure. The maximum molar amount of sulfate incorporated in hydroxylapatite (prepared in the presence of Na + ) is more than three times lower than the maximum molar amount of carbonate that can be incorporated, a difference that can be explained by the relative solubilities of the substituted apatites. The unit-cell parameters determined for both sulfated calcium and strontium hydroxylapatites synthesized with the sodium counter ion show a slight increase in the a -axis length and a nearly constant c -axis length with increasing sulfate content. The difference in the variation of unit-cell parameters with anion content can be rationalized by the difference in size of the anion. The results indicate that sulfate can be incorporated into biomaterials such as apatite or in composites with calcium sulfate and that the design of new apatites and composites could include the use of medically desirable counter cations.

A Versatile Method to Fabricate Highly In‐Plane Aligned Conducting Polymer Films with Anisotropic Charge Transport and Thermoelectric Properties: The Key Role of Alkyl Side Chain Layers on the Doping Mechanism

A general method is proposed to produce oriented and highly crystalline conducting polymer layers. It combines the controlled orientation/crystallization of polymer films by high‐temperature rubbing with a soft‐doping method based on spin‐coating a solution of dopants in an orthogonal solvent. Doping rubbed films of regioregular poly(3‐alkylthiophene)s and poly(2,5‐bis(3‐dodecylthiophen‐2‐yl)thieno[3,2‐b]thiophene) with 2,3,5,6‐tetrafluoro‐7,7,8,8‐tetracyanoquinodimethane (F4TCNQ) yields highly oriented conducting polymer films that display polarized UV–visible–near‐infrared (NIR) absorption, anisotropy in charge transport, and thermoelectric properties. Transmission electron microscopy and polarized UV–vis–NIR spectroscopy help understand and clarify the structure of the films and the doping mechanism. F4TCNQ− anions are incorporated into the layers of side chains and orient with their long molecular axis perpendicular to the polymer chains. The ordering of dopant molecules depends closely on the length and packing of the alkyl side chains. Increasing the dopant concentration results in a continuous variation of unit cell parameters of the doped phase. The high orientation results in anisotropic charge conductivity (σ) and thermoelectric properties that are both enhanced in the direction of the polymer chains (σ = 22 ± 5 S cm−1 and S = 60 ± 2 µV K−1). The method of fabrication of such highly oriented conducting polymer films is versatile and is applicable to a large palette of semiconducting polymers.

Energetics of a Uranothorite (Th1–xUxSiO4) Solid Solution

High-temperature oxide melt solution calorimetric measurements were completed to determine the enthalpies of formation of the uranothorite, (USiO4)x–(ThSiO4)1–x, solid solution. Phase-pure samples with x values of 0, 0.11, 0.21, 0.35, 0.71, and 0.84 were prepared, purified, and characterized by powder X-ray diffraction, electron probe microanalysis, thermogravimetric analysis and differential scanning calorimetry coupled with in situ mass spectrometry, and high-temperature oxide melt solution calorimetry. This work confirms the energetic metastability of coffinite, USiO4, and U-rich intermediate silicate phases with respect to a mixture of binary oxides. However, variations in unit cell parameters and negative excess volumes of mixing, coupled with strongly exothermic enthalpies of mixing in the solid solution, suggest short-range cation ordering that can stabilize intermediate compositions, especially near x = 0.5.

Novel multiferroic (Pb1 − 3x/2Ndx)(Ti0.98 − yFeyMn0.02)O3 ceramics with coexisting ferroelectricity and ferromagnetism at ambient temperature

We report the evolution of structural, dielectric, ferroelectric and ferromagnetic properties in novel (Pb1−3x/2Ndx)(Ti0.98−yFeyMn0.02)O3 perovskite ceramics(x=0.08, 0<y<0.05). We found room-temperature ferroelectric polarization and ferromagnetism for higher amount of iron ions(y≥0.04). The paraelectric-ferroelectric phase transition occurred between 650 and 670K for 0≤y≤0.05. Ferromagnetic hysteresis was measured at different temperatures on samples with y≥0.04. Detailed structural analysis evidenced the variation of unit cell parameters with y increasing, confirming the substitution of the iron element in the lattice. 57Fe Mössbauer spectroscopy evidenced that iron ions occupy Ti positions in the perovskite lattice, with the oxidation state Fe3+ and two coordination types. X-ray photoelectron spectroscopy confirmed the presence of iron only as Fe3+ and, moreover, evidenced the presence of a substantial amount of Ti3+ ions in the structure. The presence of both Fe3+ (spin 5/2) in different coordinations as well as Ti3+ (spin 1/2) magnetic ions in B-site positions drives the occurrence of magnetic properties from low temperature to above room temperature, through superexchange Fe3+-O-Fe3+, Fe3+-O-Ti3+ and Ti3+-O-Ti3+ interactions. The finding of coexistent ferroelectric and ferromagnetic properties in these compounds ground the route to facile synthesis of multiferroics by simply doping a classical perovskite ferroelectric material like PbTiO3 with an adequate amount of transition magnetic ions.

Crystal Chemistry of the Wyllieite Group of Phosphate Minerals

Abstract Three samples of minerals belonging to the wyllieite mineral group were structurally investigated: wyllieite from the Buranga pegmatite, Rwanda (A); wyllieite from the Malpensata pegmatite, Italy (B); and qingheiite from the Santa Ana pegmatite, Argentina (C). Their crystal structures were refined, based on single-crystal X-ray diffraction data, to R 1 = 2.72% (A), 3.53% (B), and 2.46% (C). Unit-cell parameters are: a 11.954(2), b 12.439(2), c 6.406(1) A, β 114.54(1)° (A); a 11.983(1), b 12.423(1), c 6.381(1) A, β = 114.54(1)° (B); a 11.878(3), b 12.448(2), c 6.438(2) A, β 114.49(1)° (C). The structure consists of kinked chains of edge-sharing octahedra stacked parallel to {101}. These chains are formed by a succession of M(2a)–M(2b) octahedral pairs, linked by slightly larger M(1) octahedra. Equivalent chains are connected in the b direction by the P(1), P(2a), and P(2b) phosphate tetrahedra to form sheets oriented perpendicular to [010]. These interconnected sheets produce channels parallel to c , channels that contain the large X cations. The X(1a) site is coordinated by anions in a distorted octahedral coordination, whereas the X(1b) site coordination can be described as a very distorted cube. The morphology of the X(2) coordination corresponds to a very distorted gable disphenoid with a [7 + 1] coordination, similar to the coordination of the A(2)9 site in the alluaudite structure. The structural features of these phosphate minerals are compared to those of other wyllieite-type phosphates: ferrorosemaryite, rosemaryite, and qingheiite-(Fe 2+ ). These new structural data indicate that Al is predominant at the M(2a) site in the investigated samples, with Fe 2+ , Fe 3+ , or Mg at the M(2b) site. Variations of unit-cell parameters, of bond distances, and of distortion coefficients among members of the wyllieite group are discussed in detail.

Синтез нового сложного бората KBaSm(BO3)2

A novel compound containing three cation alkali, alkali earth, rare earth orthoborate KBaSm(BO3)2 was synthesized by using two-step solid-state method. Results of powder X-ray diffraction analysis (XRD) and FTIR spectroscopy showed that this compound is isostructural with known compounds KBaY(BO3)2 [1] and KBaTbB2O6 [2] and refers to trigonal crystal system (RǮm space group with unit cell parameters of crystalline lattice а=5,4845(10) A, с=18,135(13), Z=3). KBaSm(BO3)2 was obtained at a temperature of 825°C from initial reactants: samarium (III) oxide, barium and potassium carbonates and boric acid. Among KBaSm(BO3)2 – KBaTb(BO3)2 – KBaY (BO3)2 observed a regular linear variation of unit cell parameters, as well as regular shift of the bands in the IR spectra, depending on the size of the rare earth cation.