Changes In Unit Cell Parameters Research Articles

Photoluminescence of complete solid solutions α-Y1-xEuxB5O9 by sol-gel synthesis and thermal decomposition from Y1-xEux[B6O9(OH)3

Completed solid solutions of Y1-xEux[B6O9(OH)3] were prepared by boric acid flux method and the structure of Eu[B6O9(OH)3] was determined by single crystal X-ray diffraction (XRD). The successful cationic doping was supported by the linear change of unit cell parameters obtained by Le Bail fitting on powder XRD. Thermal treatments on Y1-xEux[B6O9(OH)3] will lead to the dehydration, re-crystallization into TD-α-Y1-xEuxB5O9, and decomposition to α-Y1-xEuxB3O6 eventually. For comparison, the sol-gel method was also applied to prepare SG-α-Y1-xEuxB5O9. Rietveld refinements on powder XRD was applied to obtain the crystallographic data for α-YB5O9. PL investigation indicated that the existence of hydroxyl groups weakened the Eu3+ charge transfer (CT) in Y1-xEux[B6O9(OH)3]. In α-Y1-xEuxB5O9, an intense CT absorption was detected and a bright right emission was observed. Moreover, both series of phosphors exhibited a right shift of CT maximum wavelength due to the expansion of unit cell and the delayed concentration at x = 0.6.

Structural Changes in Ytterbium Ferrite YbFe2O4 in the Temperature Range From–150 °C TO 300 °C

Structural changes and thermal expansion of the iron ferrite sample YbFe2O4 of a rhombohedral modification are studied by high-temperature X-ray diffraction and differential thermal analysis. It is demonstrated that no phase transitions are observed in the temperature range from–150 °C to 300 °С. There are only anisotropic changes in unit cell parameters due to changes in Yb–O and Fe–O bond lengths.

High-Temperature Studies of the Thermal Expansion of FeNb2O6

High-temperature X-ray diffraction is used to study structural changes and thermal expansion of the synthesized iron niobate sample FeNb2O6 of the orthorhombic modification. It is demonstrated that no phase transformations are observed in the temperature range 30–1230 °C; there are only anisotropic changes in unit cell parameters. The temperature dependences of the unit cell parameters are approximated by third order polynomials. Tensor coefficients of the thermal expansion are calculated based on the obtained data. The Schneider-Eberhard formalism is used for the quantitative estimation of thermal expansion anisotropy.

Grain size effects on irradiated CeO2, ThO2, and UO2

Microcrystalline and nanocrystalline UO2, ThO2, and CeO2 (∼2 μm and∼20 nm particle size, respectively) were irradiated with 946 MeV Au ions at room temperature and characterized by synchrotron X-ray diffraction, Raman spectroscopy, and transmission electron microscopy. All samples show a small increase in unit cell parameter as a function of ion fluence (0.17 ± 0.03% for CeO2 and 0.11 ± 0.03% for ThO2), except microcrystalline UO2, which displays a small contraction of the unit cell (−0.06 ± 0.02%). Raman spectroscopy measurements of microcrystalline UO2 indicate an increase in nonstoichiometry after irradiation. All bulk materials are subject to an increase in heterogeneous microstrain, most notably UO2, implying that the relatively small changes in unit cell parameter are accompanied by substantial local disorder induced by isolated defects. The magnitude of volumetric swelling for all materials is larger in the nanocrystalline form as compared with the microcrystalline form (0.38 ± 0.60% for CeO2, 0.14 ± 0.03% for ThO2, and 0.52 ± 0.13% for UO2). ThO2 shows the smallest difference in swelling between the microcrystalline and nanocrystalline samples (∼0.03%). All nanocrystalline materials exhibit irradiation-induced grain coarsening along with a decrease in heterogeneous microstrain with increasing ion fluence, except nanocrystalline CeO2, which shows no observable change in grain size and a slight increase in heterogeneous microstrain attributed to the accelerated formation of a secondary Ce11O20 phase evidenced in the X-ray diffraction data, present in both nanocrystalline and microcrystalline materials. Surprisingly, nanocrystalline UO2 exhibits a significant degree of swelling indicative of a decrease in oxygen content along with an increase in disorder induced by oxygen loss at grain boundaries during irradiation, based on the analysis of X-ray diffraction and Raman spectroscopy.

High pressure magnetic, structural, and electronic transitions in multiferroic Ba3NbFe3Si2O14

The magnetic, structural, and electronic properties of multiferroic Ba3NbFe3Si2O14 from the langasite family were investigated by several methods including synchrotron X-ray diffraction (XRD) and synchrotron Mössbauer source (SMS) technique at high hydrostatic pressures (up to 60 GPa) created in diamond anvil cells. A cascade of structural phase transitions at pressures of about 3.5, 17.5, and 41 GPa was revealed by structural XRD, magnetic SMS, and electronic methods, including Raman, Mössbauer, and optical absorption. The transition at 17.5 GPa leads to strong changes in unit cell parameters and a sharp drop in the cell volume by about 7%. This drastically changes the magnetic properties of the crystal, which separates into two magnetic phases. The Néel temperature TN in one of the phases is increased up to 100 K, which is more than three times higher than the TN value of the parent compound (∼27 K). Above 41 GPa, the optical gap decreases to about 0.7 eV, implying a transition from dielectric to a semiconducting state, while the TN value of the magnetic phase decreases from 100 to 58 K. The magnetic transitions are explained by the redistribution of Fe ions between tetrahedral and possibly octahedral (or/and interstitial) sites resulting in enhancement of exchange interactions. The appearance of a low spin state of Fe3+ ions in octahedral sites is also discussed.

Effects of Aging on Transformation of Biogenic Magnetite Nanoparticles

This study examined the microbial synthesis of magnetite and Pd/Zn-substituted magnetite using metal-reducing bacteria (Clostridium sp.), and the mineralogical characteristics of various types of magnetite formed initially and transformed minerals aged for 5 years. XRD, SXRD, and TEM-EDS analyses were used to characterize the mineralogy, crystal structure, chemistry, shape, and size distribution of the magnetites and transformed minerals. The metal-reducing bacteria reduced akaganeite and Pd/Zn-akaganeite to magnetite and Pd/Zn-substituted magnetite using glucose as an electron donor, respectively. Metal substitution of Pd and Zn within the magnetite structure resulted in a decrease in the unit-cell parameter of the magnetite crystals. After 5 years, the biogenic magnetite showed changes in unit-cell parameters and transformation to siderite during prolonged cultivation under anaerobic conditions. These results indicate that long-term aging may affect the mineralogical transformation and alter the nano-sized crystal structure.

Plausible domain configurations and phase contents in two- and three-phase BaTiO3-based lead-free ferroelectrics

We have carried out a comparative study of plausible non-180° domain configurations in the two- and three-phase states of lead-free ferroelectrics Ba(Ti1−xZrx)O3 (0.02 ⩽ x ⩽ 0.08) and (Ba0.85Ca0.15)(Ti0.90Zr0.10)O3, respectively, using the elastic matching approach. The phase contents and stress-relief conditions in Ba(Ti0.93Zr0.07)O3 and (Ba0.85Ca0.15)(Ti0.90Zr0.10)O3 strongly depend on domain types in the rhombohedral R3m phase, whereas domains of the orthorhombic Amm2 phase influence two-phase states in Ba(Ti0.98Zr0.02)O3. Changes in unit-cell parameters of (Ba0.85Ca0.15)(Ti0.90Zr0.10)O3 at poling lead to the complete stress relief in three-phase (P4mm + Amm2 + R3m) structures by increasing the volume fraction of the R3m phase. A link between the heterophase/domain structures and high piezoelectric activity in (Ba0.85Ca0.15)(Ti0.90Zr0.10)O3 is discussed. Based on our results, we state that equal or almost equal volume fractions of the domain types at the three-phase coexistence in (Ba0.85Ca0.15)..(Ti0.90Zr0.10)O3 can lead to an enhanced contribution from domain-wall displacements and therefore, to the large piezoelectric response in this important lead-free ferroelectric compound.

Structural, FTIR and Dielectric Study of Lithium Doped KDP Crystals

Potassium Dihydrogen Phosphate (KDP) crystals are well known for nonlinear optical (NLO) properties and find different optical applications. In the present study, various amount of lithium doped KDP single crystals were grown by slow solvent evaporation method. For doping lithium chloride was mixed with KDP solution in 1, 3 and 5 weight percent. The grown crystals were transparent and prismatic in nature with maximum dimension of 5 cm × 1.5 cm × 0.5 cm. The presence of lithium was detected by flame test. The powder XRD study indicated single phase nature of the grown crystals and the doping caused minor change in the KDP structure, which was confirmed by the minor change in unit cell parameters. From FTIR study the functional groups like O-H, P-O, P-OH were identified but no major change due to lithium doping was found. The dielectric study was carried out in the range from 10 kHz to 10MHz indicated sharp decrease in dielectric constant with frequency of applied field after 70 kHz. The AC conductivity increased with increase of frequency. The dielectric constant was found to be sensitive to doping in KDP.

Effect of calcium doping on La4(Ti2O8)O2 structure and conductivity

La4-xCaxTi2O10-δ (x = 0; 0.1; 0.2) powders were synthesized by a modified Pechini method. Thermal treatement of the powders under reducing atmosphere (2% H2 in Ar) and their sintering in air led to changes in unit cell parameters and unit cell volume. A decrease in long range ordering and symmetry with the increase in dopant content after sintering was evidenced by Raman spectroscopy, in agreement with the results of conductivity measurement performed under air. The ionic conductivity increases with two orders of magnitude after doping with calcium. The activation energy of conduction for doped samples decreases compared to the undoped sample, indicating a change in the conduction mechanism. Doped samples exhibit an increase in conductivity and activation energy of conduction after exposure to highly reducing atmosphere.

The effect of Ca-Pb and P-As substitutions on the solubulity of hydroxylapatites [abstract

Hydroxylapatites are important biomaterials. Substitutions of Pb for Ca and As for P in hydroxylapatites are recently intensively studied due to their significance in the environmental immobilization of Pb and As (Lee et al. 2009; Chlebowska et al. 2015; Motyka et al. 2015) The general chemical formula of minerals in the apatite group is expressed by A 5 (XO 4 ) 3 Z, where A are bivalent cations (e.g., Ca 2+ or Pb 2+ , cations are distributed on two distinct crystallographic sites), XO 4 is a trivalent oxyanion (e.g., PO 4 3 - , AsO 4 3 - ), and Z is a monovalent anion (OH, F, Cl, or O). Positions Z and X may be partly filled with carbonate CO 3 2- . The structure of hydroxylapatite allows for unlimited substitutions of Pb 2+ for Ca 2+ and AsO 4 3- for PO 4 3- . The ability of lead and arsenic apatites to immobilize these toxic elements result from their high durability and low solubility at the conditions on the Earth surface. Various apatites possess different thermodynamic properties including different solubility in aqueous solutions but the systematic variation of these properties in solid solution series is poorly undertsood. The main objective of this research is determination of systematic variation in the solubilities of hydroxylapatites resulting from cationic substitutions of Pb 2+ for Ca 2+ and anionic substitutions of AsO 4 3- for PO 4 3- in their structure. Three solid solution series were synthesized: HPY hydroxypyromorphite Pb 5 (PO 4 ) 3 OH – HAP hydroxyapatite Ca 5 (PO 4 ) 3 OH HMi hydroxymimetite Pb 5 (AsO 4 ) 3 OH – JBM johnbaumite Ca 5 (AsO 4 ) 3 OH HAP hydroxyapatite Ca 5 (PO 4 ) 3 OH – JBM johnbaumite Ca 5 (AsO 4 ) 3 OH The phases were synthesized from aqueous solutions at high pH above 8, at ambient temperature, by dropwise mixing of chemical reagents. The products are white, fine, homogeneous crystalline powders. Chemical composition determined by SEM/EDS is close to theoretical. X-ray diffraction confirms their crystalline structure and systematic changes in unit cell parameters with ionic substitution. Dissolution experiments were run in thermostatic bath at 25°C. An aliquot of 0,5g of apatite was dissolved in 250 mL of 0,05M NH 4 NO 3 background solution at pH in the range of 3.5 – 5.0. Background solution was used to keep the ionic strength constant. The dissolution was carried out for 3 months. The bottles were manually stirred at least two times a week. The solution was syringe-sampled periodically and filtered through 0.2 μm polycarbonate filter to remove the suspended solids. The concentration of Pb and Ca was determined by atomic absorption spectroscopy. The concentration of dissolved phosphates and arsenates was determined by UV-vis colorimetry using a molybdenum blue method. The plateau on concentration evolution patterns from the dissolution experiments was observed to determine equilibrium in the suspensions. Dissolution of all the phases at the conditions of these experiments is incongruent. An increase in solution pH resulting from dissolution was observed in all cases. The system was considered in equilibrium when at least three consecutive samples showed identical concentration of Ca 2+ or AsO 4 3- . The equilibrium in HPY series was assumed by analogy. All the concentrations were recalculated to activities using PHREEQC model with Llnl database. The solubility K sp determined for the endmembers at 25°C conform with the literature data and equal to: HPY-K sp =10 -77,31 , HAP-K sp =10 -55,66 , HMi-K sp =10 -71,56 , and JBM K sp =10 -37,76 . This confirms that, despite the incongruency of dissolution, the experimental procedure and the calculation scheme provide with reliable approximation of the solubilities. The most soluble phase is johnbaumite Ca 5 (AsO 4 ) 3 OH. The solubility of all hydroxylapatites decreases linearly with the increase of Pb and P content. These trends do not correlate with the changes in Gibbs free energy of formation of the phases in question. This indicates that structural (e.g. the size of the ions) and the chemical factors (e.g. electronegativity) play the dominant role in the solubility of substituted hydroxylapatites.

Growth, non-linear optical, photoconductivity and dielectric characterization of pure and EDTA doped tris-glycine zinc chloride single crystals for LiDAR

Non-linear optical crystals which are used as frequency converters to access various spectral ranges like visible or UV are key components of (Light Detection and ranging) LiDAR systems. For this purpose promising non-linear optical crystals like tris-glycine zinc chloride (TGZC) a nonlinear optical material, with the additive Ethylenediaminetetraacetic acid (EDTA) is grown successfully by slow cooling technique. In order to improve the device characteristics of TGZC crystals, organic dopant EDTA were incorporated into the parent crystals. Observation of the crystal growth, behavior and measurement of growth kinetics revealed a strong dependence of growth rate on the additive. The slight change in unit-cell parameters of the doped compound from the pure TGZC were confirmed by single crystal X-ray diffraction analysis. The presence of functional groups is estimated qualitatively by FTIR analysis. The UV–vis spectrum shows a cut-off wavelength less than 300nm. The photocurrent of both pure and doped crystals is more than that of the dark current. Microhardness studies carried out using Leitz Weitzler hardness tester at room temperature showed an increase due to doping. The dielectric loss is low at high frequency and this behavior is of vital importance for NLO applications. In this paper, an attempt has been made on the growth and characterization of nonlinear optical crystal and theoretical aspects of single crystals as frequency convertors in Atmospheric Remote Sensing is discussed.

Structural and particle size characteristics of lithium carbonate after mechanical activation and heat treatment

This paper examines the structural and particle size characteristics of lithium carbonate after mechanical processing in an AGO-2 planetary activator, followed by heat treatment. Milling increases the specific surface area of lithium carbonate, changes the aggregate size distribution, reduces the crystallite size, increases the lattice strain in the material, and changes the monoclinic cell parameters. Subsequent heat treatment of the mechanically activated samples in the range 25–500°C is accompanied by recrystallization of the material: its specific surface area and lattice strain decrease, the crystallite size increases, and its unit-cell parameters change.

Structural transformations in crystals induced by radiation and pressure. Part 1. How pressure influences the intramolecular photochemical reactions in crystals

The main aim of the studies in this paper is to gain knowledge on the path of structural transformations resulting from the photocyclization in 2-tert-butylphenylphenylmethanone crystals at low and high pressures and also to carry out a comparative analysis of the results at different pressures. This work is the first example of these types of studies in scientific literature. We determined the structure of: pure reactant crystals, i.e. only containing reactant molecules, at 0.1 MPa, 0.55 GPa, 1.27 GPa and 1.50 GPa; pure product crystals, i.e. only containing product molecules, at 0.55 GPa and 1.27 GPa; and partly reacted crystals (ten structures), i.e. containing both reactant and product molecules in various proportions to each other, at 0.1 MPa (two structures), 0.55 GPa (three structures), 1.27 GPa (three structures) and 1.50 GPa (two structures). The studies have shown that (a) there is no phase transition when an increase in pressure is imposed onto the crystals, (b) the unit cell parameters change non-linearly with an increase in pressure, (c) the photochemical reaction was conducted in a homogeneous manner in the examined crystals, (d) the reaction brings about different modes of changes in the unit cell parameters at different pressures (e) the reaction proceeds faster at the end rather than at the beginning regardless of the pressure imposed onto the crystals.

Effect of a tetragonal phase on heterophase states in perovskite-type ferroelectric solid solutions

Results on the role of the ferroelectric tetragonal (P4mm) phase in an elastic matching and phase coexistence are discussed for perovskite-type solid solutions (1−t)BiFeO3–tPbTiO3, (1−z)Pb(ZrwTi1−w)O3–zPb(Zn1/3Nb2/3)O3 and (1−r)(Na1/2Bi1/2)TiO3–rPbTiO3 near morphotropic phase boundaries. An important feature is a combination of single- and polydomain regions of the tetragonal phase that coexists with the adjacent ferroelectric phase, either monoclinic or rhombohedral, at the complete stress relief in a heterophase sample. A dependence of the volume fraction of the tetragonal phase on the composition and domain types is found for various heterophase states in the aforementioned systems. The remarkable role of the tetragonal phase and its unit-cell parameters behaviour is discussed. Some correlations between changes in unit-cell parameters of the tetragonal phase and its volume fraction are revealed. Agreement between predicted and known experimental data on the phase contents in the studied ferroelectric solid-solution systems is stated.

Iron-Based Metal–Organic Frameworks MIL-88B and NH2-MIL-88B: High Quality Microwave Synthesis and Solvent-Induced Lattice “Breathing”

Iron-based MIL-88B and NH2-MIL-88B microcrystals with high dispersibility and uniform size were successfully synthesized by using a rapid microwave-assisted solvothermal method. By carefully controlling the reaction conditions, the microwave method provided superior quality MIL-88B crystals in high yields and excellent phase purity. Framework flexibility was observed for both MIL-88B-Fe and NH2-MIL-88B-Fe frameworks in various solvents, which however significantly differs between the two materials. MIL-88B-Fe shrinks reversibly by about 25% only when it is dispersed in the strongly hydrogen bonding solvents water or methanol. In contrast, NH2-MIL-88B-Fe shrinks up to 33% upon replacement of dimethylformamide (DMF) by any other solvent studied (benzene, chloroform, acetone, acetonitrile, methanol, water). The change in unit cell parameters (shortening of the a axis) can be seen macroscopically, although the overall integrity of the materials is maintained. We suggest that hydrogen bonding between the oxyge...

Evolution of atomic ordering in fine-grained YBa2Cu3O y high-temperature superconductors and its effect on superconducting transition temperature

Regularities of changes in unit cell parameters and superconducting properties of the optimally doped fine-grained YBa2Cu3O y (y ≈ 6.92) high-temperature superconductors (HTSC) at the initial stage of the high-rate formation of orthorhombic crystal structure from the activated mixture of initial components are investigated. The orthorhombic distortion degree σ and the superconducting transition temperature T c are characterized by uncommon correlation being different from that characteristic for coarse-grained samples. It is shown that there are much higher T c values in fine-grained samples for a given parameter σ. It is concluded that all of the observed regularities are related to specific features of atomic disorder characteristic for fine-grained samples.

Cation substitution in synthetic meridianiite (MgSO4·11H2O) II: variation in unit-cell parameters determined from X-ray powder diffraction data

We have prepared aqueous MgSO4 solutions doped with various divalent metal cations (Ni2+, Zn2+, Mn2+, Cu2+, Fe2+, and Co2+) in proportions up to and including the pure end-members. These liquids have been solidified into fine-grained polycrystalline blocks of metal sulfate hydrate + ice by rapid quenching in liquid nitrogen. In a companion paper (Fortes et al., in Phys Chem Min 39) we reported the identification of various phases using X-ray powder diffraction, including meridianiite-structured undecahydrates, melanterite- and epsomite-structured heptahydrates, novel enneahydrates and a new octahydrate. In this work we report the changes in unit-cell parameters of these crystalline products where they exist over sufficient dopant concentrations. We find that there is a linear relationship between the rate of change in unit-cell volume as a function of dopant concentration and the ionic radius of the dopant cation; large ions such as Mn2+ produce a substantial inflation of the hydrates’ unit-cell volume, whereas smaller ions such as Ni2+ produce a modest reduction in unit-cell volume. Indeed, when the data for all hydrates are normalised (i.e., divided by the number of formula units per unit-cell, Z, and the hydration number, n), we find a quantitatively similar relationship for different values of n. Conversely, there is no relationship between the degree of unit-cell inflation or deflation and the limit to which a given cation will substitute into a certain hydrate structure; for example, Co2+ and Zn2+ affect the unit-cell volume of MgSO4·11H2O to a very similar degree, yet the solubility limits inferred in our companion paper are >60 mol. % Co2+ and <30 mol. % Zn2+.

Correlation among Dielectric Properties, Vibrational Modes, and Crystal Structures in Ba[SnxZn(1–x)/3Nb2(1–x)/3]O3 Solid Solutions

Ba[SnxZn(1–x)/3Nb2(1–x)/3]O3 (x = 0.0, 0.16, 0.226, 0.32, 0.4) solid solution ceramics were synthesized by the conventional solid-state reaction method. Crystal structures are studied by X-ray diffraction, and vibrational modes are obtained by Raman spectroscopy and Fourier transform far-infrared reflection spectroscopy. The correlation among dielectric properties, lattice vibrational modes, and crystal structures are discussed by analyses of vibrational modes. Spectroscopic and structural data show sensitivity of dielectric properties to structures of samples with Sn4+ concentration, and optimized dielectric properties of Ba[SnxZn(1–x)/3Nb2(1–x)/3]O3 are found where x = 0.32. The changes of unit cell parameters and the bulk densities of the samples with Sn4+ concentration are discussed. The changes of dielectric properties with the Raman modes and their full width at half-maximum are obtained. The frequencies of phonon modes are determined, and the widths of phonon modes are related to ionic radii for th...

High-T behaviour of gedrite: thermoelasticity, cation ordering and dehydrogenation

The thermoelastic behaviour of a natural gedrite having the crystal-chemical formula ANa0.47B(Na0.03 Mg1.05 Fe0.862+ Mn0.02 Ca0.04) C(Mg3.44 Fe0.362+ Al1.15 Ti0.054+) T(Si6.31 Al1.69)O22W(OH)2 has been studied by single-crystal X-ray diffraction to 973 K (Stage 1). After data collection at 973 K, the crystal was heated to 1,173 K to induce dehydrogenation, which was registered by significant changes in unit-cell parameters, M1–O3 and M3–O3 bond lengths and refined site-scattering values of M1 and M4 sites. These changes and the crystal-chemical formula calculated from structure refinement show that all Fe2+ originally at M4 migrates into the ribbon of octahedrally coordinated sites, where most of it oxidises to Fe3+, and there is a corresponding exchange of Mg from the ribbon into M4. The resulting composition is that of an oxo-gedrite with an inferred crystal-chemical formula ANa0.47B(Na0.03 Mg1.93 Ca0.04) C(Mg2.56 Mn0.022+ Fe0.102+ Fe1.223+ Al1.15 Ti0.054+) T(Si6.31 Al1.69) O22W[O1.122− (OH)0.88]. This marked redistribution of Mg and Fe is interpreted as being driven by rapid dehydrogenation at the H3A and H3B sites, such that all available Fe in the structure orders at M1 and M3 sites and is oxidised to Fe3+. Thermoelastic data are reported for gedrite and oxo-gedrite; the latter was measured during cooling from 1,173 to 298 K (Stage 2) and checked after further heating to 1,273 K (Stage 3). The thermoelastic properties of gedrite and oxo-gedrite are compared with each other and those of anthophyllite.

Analysis of the Photomagnetic Properties of Cyano-Bridged Heterobimetallic Complexes by X-Ray Diffraction

Single crystal synchrotron X-ray diffraction measurements have been carried out on [Nd(DMF)(4)(H(2)O)(3)(μ-CN)Fe(CN)(5)]·H(2)O (DMF = dimethyl-formamide), 1; [Y(DMF)(4)(H(2)O)(3)(μ-CN)Fe(CN)(5)]·H(2)O, 2; [Ce(DMF)(4)(H(2)O)(3)(μ-CN)Fe(CN)(5)]·H(2)O, 3; [Sm(DMF)(4)(H(2)O)(3)(μ-CN)Fe(CN)(5)]·H(2)O, 4; [Tb(DMF)(4)(H(2)O)(3)(μ-CN)Fe(CN)(5)]·H(2)O, 5; [Yb(DMF)(4)(H(2)O)(3)(μ-CN)Fe(CN)(5)]·H(2)O, 6; and [Nd(DMF)(4)(H(2)O)(3)(μ-CN)Co(CN)(5)]·H(2)O, 7, at 15(2) K with and without UV illumination of the crystals. Significant changes in unit cell parameters are observed for all of the iron-containing complexes, while compound 7 shows no response to UV illumination. These results are consistent with previous results and are furthermore reproduced by powder synchrotron X-ray diffraction for compounds 1 and 7. Photoexcited crystal structures have been determined for 1-6 from refinements of two-conformer models, and excited state occupancies in the range 80-94% are found. Significant bond length changes are observed for the Fe-ligand bonds (up to 0.06 Å), the cyano bonds (up to 0.02 Å), and the lanthanide-ligand bonds (up to 0.1 Å). On the contrary, powder X-ray diffraction on the simple compound K(3)Fe(CN)(6), 8, upon UV illumination does not show any structural changes, suggesting that the photomagnetic effect requires the presence of both the transition metal and the lanthanide ion. Photomagnetic measurements show an increase in magnetization of the excited state of 1 of up to 3%, which is much diminished compared with previously published values of 45%. Furthermore, they show that the isostructural complex [La(DMF)(4)(H(2)O)(3)(μ-CN)Fe(CN)(5)]·H(2)O, 9, exhibits identical magnetic responses in the UV-induced excited crystal structure.