Search Results (26)

O3-type layered transition-metal oxides are widely regarded as promising cathode materials for sodium-ion batteries due to their intrinsically high sodium content and favorable energy density. Nevertheless, their practical rate capability is hindered by sluggish Na⁺ transport and relatively high diffusion barriers. To address this issue, elemental substitution has emerged as an effective modification strategy. In this work, fluorine (F), characterized by strong electronegativity and a small ionic radius, is introduced to partially substitute oxygen in the bulk lattice of O3-type NaNi_1/3Fe_1/3Mn_1/3O₂ (NNFM). First-principles calculations demonstrate that F incorporation leads to an expansion of the interlayer spacing along the c-axis and a weakening of Na–O interactions, both of which facilitate Na⁺ migration. Among the considered configurations, Mn-adjacent substitution exhibits the lowest formation energy, indicating enhanced thermodynamic stability. Furthermore, electronic structure analysis reveals a reduced band gap (from 0.515 eV to 0.342–0.356 eV) and strengthened O-2p/Mn-3d orbital hybridization, contributing to improved electronic conductivity. These findings provide atomistic insights into F-induced modulation mechanisms and suggest an effective pathway for optimizing Na⁺ transport in O3-type cathodes. Full article

Doping lead-free halide perovskite nanocrystals with trivalent lanthanide ions has emerged as a promising strategy for engineering their optical properties in various photonic applications. Here, we report the design and synthesis of a series of lead-free double halide perovskite (Cs₂Na(In/Y/Gd)Cl₆) nanocrystals co-doped with a pair of different lanthanides (e.g., Tb³⁺, Dy³⁺, and Eu³⁺) as emission centers, and ns² ions (Sb³⁺ or Bi³⁺) as sensitizers. The tunability of the delayed photoluminescence spectral density was achieved through the selective excitation of lanthanide dopants either via ligand-to-metal charge transfer (e.g., Eu³⁺) or via ns² ion s-p transitions (e.g., Dy³⁺ or Tb³⁺). The intensities of the narrow lanthanide f-f emission bands can, therefore, be tuned by modulating the excitation wavelength and/or dopant ratio, allowing for the accurate engineering of the emission color coordinates and spectral density. We also demonstrated time-resolved tuning of the photoluminescence spectral density for the investigated nanocrystal host lattices co-doped with transition-metal (Mn²⁺) and lanthanide ions, owing to a large difference between the decay dynamics for Mn²⁺ d-d and lanthanide f-f transitions. The rational co-doping of double halide perovskite nanocrystals reported in this work provides a new strategy for generating pre-designed multilevel luminescent signatures for protection against counterfeiting. Full article

The global decarbonisation strategy has accelerated the shift toward renewable energy and electric transport, demanding advanced electrochemical energy storage systems. Conventional anodes such as graphite and silicon composites face challenges in conductivity, stability and cycling performance. MXenes, a class of two-dimensional (2D) materials, offer promising alternatives owing to their metallic conductivity, tunable surface chemistry and high theoretical capacity. Here, we synthesise and characterise Mo₂TiC₂T_x and V₂CT_x (T = O, OH, F and/or Cl) MXenes for lithium-ion battery anodes and supercapacitors. Unlike Ti₃C₂T_x, which stores charge via intercalation and surface redox reactions, Mo₂TiC₂T_x and V₂CT_x exhibit conversion-type mechanisms. We also identify novel V₂C–VO_x heterostructures, achieving a specific capacitance of 532.4 F g⁻¹ at 2 mV s⁻¹ and an initial capacity of 493.3 mAh g⁻¹ at 50 mA g⁻¹ in lithium half-cells, with a low decay rate of 0.071% per cycle over 200 cycles. Pristine Mo₂TiC₂T_x shows 391.7 mAh g⁻¹ at 50 mA g⁻¹, decaying by 0.109% per cycle. These results experimentally validate theoretical predictions, revealing how MXene structure and transition metal chemistry govern electrochemical behaviour, thus guiding electrode design for next-generation batteries and supercapacitors. Full article

Zero-dimensional (0D) rare-earth-based metal halides show great potential in photonic and optoelectronic applications owing to their high stability, strong exciton confinement, and tunable energy levels. However, the weak absorption and narrow 4f-4f transitions of rare-earth ions limit their performance. To address this, a series of Sb³⁺-doped Cs₃LnCl₆ (Ln: Yb, La, Eu, Ho, Ce, Er, Tb, Sm, Y) nanocrystals were synthesized via a hot-injection method to study the role of Sb³⁺ doping. Sb³⁺ incorporation induces strong broadband self-trapped exciton (STE) emission from Jahn–Teller-distorted [SbCl₆]³⁻ units and enables efficient energy transfer from STEs to rare-earth ions. As a result, the photoluminescence intensity and spectral tunability are improved, accompanied by bandgap narrowing and enhanced light absorption. Different lanthanide hosts exhibit distinct luminescence behaviors: La-based materials show dominant STE emission, while Tb-, Er-, Yb-, Ho-, and Sm-based systems display STE-mediated energy transfer and enhanced f-f emission. In Eu- and Ce-based hosts, unique mechanisms involving Eu²⁺/Eu³⁺ conversion and Ce³⁺ → STE energy transfer are observed. Moreover, composition-dependent emissions in Sb³⁺-doped Cs₃Tb/EuCl₆ enable a dual-mode color and spectral encoding strategy for optical anti-counterfeiting. This study highlights the versatile role of Sb³⁺ in tuning electronic structures and energy transfer, offering new insights for designing high-performance rare-earth halide materials for advanced optoelectronic applications. Full article

Novel Eu³⁺-doped Na₅Zn₂Gd(MoO₄)₆ triple molybdate phosphors were fabricated by the sol-gel method. The structure, morphology, and luminescent properties have been characterized by X-ray diffraction (XRD), thermogravimetric differential thermal analysis (TG-DTA), scanning electron microscopy (SEM), FTIR spectroscopy, and luminescence spectroscopy. The results indicated that the synthesized Na₅Zn₂Gd_1−x(MoO₄)₆: xEu³⁺ phosphor consisted of a pure phase with monoclinic structure. Under excitation at 465 nm, the Na₅Zn₂Gd_1−x(MoO₄)₆: xEu³⁺ phosphor exhibits an intensive red emission band around 610 nm corresponding to the transition of ⁵D₀→⁷F₂ which is much higher than that ⁵D₀→⁷F₁ at 594 nm, which was appropriate for a blue LED. According to the influence of the synthesis conditions, the phosphors showed the highest emission intensity when the doping concentration of Eu³⁺ was 25 mol.% and the molar ratio of citric acid to metal ions was 2:1. Na₅Zn₂Gd_0.75(MoO₄)₆: 0.25 Eu³⁺ with the color coordinates (x = 0.658, y = 0.341) is a more stable red phosphor for blue-based white LEDs than the commercial Y₂O₂S: Eu³⁺ red phosphor (0.48, 0.50) due to its being closer to the NTSC standard values (0.670, 0.330). Full article

The chemistry of heterometallic metal complexes continues to attract the interest of molecular inorganic chemists mainly because of the properties that different metal ions can bring to compounds. Contrary to the plethora of 3d–4f- and 3d–3d′-metal complexes, complexes containing both 3d- and 4d-metal ions are much less studied. The choice of the bridging organic ligand is of paramount importance for the synthesis of such species. In the present work, we describe the use of the potentially tetradentate NOO′O″ Schiff bases N-(2-carboxyphenyl)salicylideneimine (saphHCOOH) and N-(4-chloro-carboxyphenyl)salicylideneimine (4ClsaphHCOOH) in Cd^II-M^III (M = Fe, Cr) chemistry. The complexes [Cd₂Fe₂(saphCOO)₄(NO₃)₂(H₂O)₂] (1), [Cd₂Cr₂(saphCOO)₄(NO₃)₂(H₂O)₂] (2), [Cd₂Fe₂(4ClsaphCOO)₄(NO₃)₂(H₂O)₂] (3) and [CdCr₂(4ClsaphCOO)₄(H₂O)₃(EtOH)] (4) have been structurally characterized, the quality of the structure of the latter being poor but, permitting the knowledge of the connectivity and the main structural features. Complexes 1–3 are isostructural, but not isomorphous, possessing a variety of lattice solvent molecules (EtOH, MeCN, CH₂Cl₂, H₂O). The metal topology can be described as two isosceles triangles sharing a common Cd^II…Cd^II edge. The two Cd^II atoms are doubly bridged by two μ-aqua groups. The M^III…Cd^II sides of the triangles are each asymmetrically bridged by one carboxylate oxygen atom of a 2.2111 saphCOO²⁻/4ClsaphCOO²⁻ ligand. The core of the molecules is {Cd₂M₂(μ-O_aqua)₂(μ-OR)₄}⁶⁺, where the OR oxygen atoms are the bridging carboxylate oxygens. The coordination spheres of the metal ions in the centrosymmetric molecules are [Cd(O_aqua)₂(O_carboxylato)₄(O_nitrato)₂] and [M(N_imino)₂(O_carboxylato)₂(O_phenolato)₂]. The biaugmented trigonal prism is the most appropriate for the description of the coordination geometry of the Cd^II atoms in 1 and 3, while the geometry of these metal ions in 2 is best described as distorted triangular dodecahedral. A combination of H-bonding and π–π stacking interactions give interesting supramolecular patterns in the three tetranuclear compounds. The three metal ions in 4 define an isosceles triangle with two almost equal Cd^II…Cr^III sides. The Cd^II center is linked to each Cr^III atom through one carboxylato oxygen of a 2.2111 4ClsaphCOO²⁻ ligand. The core of the molecule is {CdCr₂(μ-OR)₂}⁶⁺, where the OR oxygen atoms are the bridging carboxylato oxygens. A tridentate chelating 1.1101 4ClsaphCOO²⁻ ligand is bonded to each Cr^III. The coordination spheres are [Cd(O_aqua)₃(O_ethanol)(O_{bridging carboxylato})₂(O_{terminal carboxylate})₂] and [Cr(O_{bridging carboxylato})(O_{terminal carboxylato})(O_phenolato)₂(N_imino)₂]. Complexes 1–4 are the first heterometallic 3d–4d complexes based on saphHCOOH and 4ClsaphCOOH. The structures are critically compared with those of previous reported Zn^II-M^III (M = Fe, Cr) complexes. The IR and Raman spectra of the complexes are discussed in terms of the coordination modes of the ligands involved. UV/VIS spectra in CH₂Cl₂ are also reported, and the bands are assigned to the corresponding transitions. The δ and ΔE_Q⁵⁷Fe-Mössbauer parameters of 1 and 3 at room temperature and 80 K suggest the presence of isolated high-spin Fe^III centers. Variable-temperature (1.8–310 K) and variable-field (0–50 kOe) magnetic studies for 1 and 2 indicate the absence of M^III…M^III exchange interactions, in agreement with the long distances (~8 Å) between the paramagnetic metal ions. The combined work demonstrates the ability of saphCOO²⁻ and 4ClsaphCOO²⁻ to give 3d–4d metal complexes. Full article

In this study, we conducted a theoretical simulation to compare the effects of various factors on the atomic and electronic structures and the magnetic properties of copper and gadolinium ions bonded to carboxylated species of (111) diamond surfaces. It was experimentally found that in the temperature range above 120 K, the magnetic moments of chelated Gd³⁺ and Cu²⁺ equal 6.73 and 0.981 Bohr magnetons, respectively. In the temperature range from 12 to 2 K, these magnetic moments sharply decrease to 6.38 and 0.88 Bohr magnetons. Specifically, we examined the effects of the number of covalent adatom–diamond substrate bridges, coordination of water molecules, and shallow carbon-inherited spins in the substrate on the physical properties of the metal center. Our simulation predicted that increasing the number of bonds between the chelated metal ion and substrate while decreasing the number of coordinating water molecules corresponded to a decrease in the magnetic moment of metal ions in a metal–diamond system. This is due to the redistribution of the electron charge density in an asymmetric metal–diamond system. By comparing our theoretical results with experimental data, we proposed configurations involving one and, in a minor number of cases, two surface –COO⁻ groups and maximum coordination of water molecules as the most realistic options for Cu- and Gd-complexes. Full article

Starting from poly(4-vinylpyridine) ((P4VP)_n), poly(2-vinylpyridine) ((P2VP)_n), and [N=P(O₂CH₂CF₃)]_m-b-P2VP₂₀ block copolymers, a series of metal-containing homopolymers, (P4VP)_n⊕MX_m, (P2VP)_n⊕MX_m, and [N=P(O₂CH₂CF₃)]_m-b-P2VP₂₀]⊕MX_m MX_m = PtCl₂, ZnCl₂, and Eu(NO₃)₃, have been successfully prepared by using a direct and simple solution methodology. Solid-state pyrolysis of the prepared metal-containing polymeric precursors led to the formation of a variety of different metallic and metal oxide nanoparticles (Pt, ZnO, Eu₂O₃, and EuPO₄) depending on the composition and nature of the polymeric template precursor. Thus, whereas Eu₂O₃ nanostructures were obtained from europium-containing homopolymers ((P4VP)_n⊕MX_m and (P2VP)_n⊕MX_m), EuPO₄ nanostructures were achieved using phosphorus-containing block copolymer precursors, [N=P(O₂CH₂CF₃)]_m-b-P2VP₂₀]⊕MX_m with MX_m = Eu(NO₃)₃. Importantly, and although both Eu₂O₃ and EuPO₄ nanostructures exhibited a strong luminescence emission, these were strongly influenced by the nature and composition of the macromolecular metal-containing polymer template. Thus, for P2VP europium-containing homopolymers ((P4VP)_n⊕MX_m and (P2VP)_n⊕MX_m), the highest emission intensity corresponded to the lowest-molecular-weight homopolymer template, [P4VP(Eu(NO₃)₃]₆₀₀₀, whereas the opposite behavior was observed when block copolymer precursors, [N=P(O₂CH₂CF₃)]_m-b-P2VP₂₀]⊕MX_m MX_m= Eu(NO₃)₃, were used (highest emission intensity corresponded to [N=P(O₂CH₂CF₃)]₁₀₀-b-[P2VP(Eu(NO₃)₃)_x]₂₀). The intensity ratio of the emission transitions: ⁵D₀ → ⁷F₂/⁵D₀ → ⁷F₁, suggested a different symmetry around the Eu³⁺ ions depending on the nature of the polymeric precursor, which also influenced the sizes of the prepared Pt°, ZnO, Eu₂O₃, and EuPO₄ nanostructures. Full article

Transition metal nitride negative electrode materials with a high capacity and electronic conduction are still troubled by the large volume change in the discharging procedure and the low lithium ion diffusion rate. Synthesizing the composite material of F-doped Fe₃N and an N-doped porous carbon framework will overcome the foregoing troubles and effectuate a preeminent electrochemical performance. In this study, we created a simple route to obtain the composite of F-doped Fe₃N nanoellipsoids and a 3D N-doped porous carbon framework under non-ammonia atmosphere conditions. Integrating the F-doped Fe₃N nanoellipsoids with an N-doped porous carbon framework can immensely repress the problem of volume expansion but also substantially elevate the lithium ion diffusion rate. When utilized as a negative electrode for lithium-ion batteries, this composite bespeaks a stellar operational life and rate capability, releasing a tempting capacity of 574 mAh g^–1 after 550 cycles at 1.0 A g^–1. The results of this study will profoundly promote the evolution and application of transition metal nitrides in batteries. Full article

Supercapacitors have the characteristics of high power density, long cycle life, and fast charge and discharge rates, making them promising alternatives to traditional capacitors and batteries. The use of transition-metal compounds as electrode materials for supercapacitors has been a compelling research topic in recent years because their use can effectively enhance the electrical performance of supercapacitors. The current research on capacitor electrode materials can mainly be divided into the following three categories: carbon-based materials, metal oxides, and conductive polymers. Nickel hydroxide (Ni(OH)₂) is a potential electrode material for use in supercapacitors. Depending on the preparation conditions, two crystal phases of nickel hydroxide, α and β, can be produced. When compared to α-NiOH, the structure of β-Ni(OH)₂ does not experience ion intercalation. As a result, the carrier transmission rate of α-Ni(OH)₂ is slower, and its specific capacitance value is smaller. Its carrier transport rate can be improved by adding conductive materials, such as graphene. β-Ni(OH)₂ was chosen as an electrode material for a supercapacitor in this study. Homemade low-pressure chemical vapor deposition graphene (LPCVD-Graphene) conductive material was introduced to modify β-Ni(OH)₂ in order to increase its carrier transport rate. The LPCVD method was used to grow high-quality graphene films on three-dimensional (3D) nickel foam substrates. Then, a hydrothermal synthesis method was used to grow β-Ni(OH)₂ nanostructures on the 3D graphene/nickel foam substrate. In order to improve the electrical properties of the composite structure, a high-quality graphene layer was incorporated between the nickel hydroxide and the 3D nickel foam substrate. The effect of the conductive graphene layer on the growth of β-Ni(OH)₂, as well as its electrical properties and electrochemical performance, was studied. When this β-Ni(OH)₂/CVD-Graphene/3D-NF (nickel foam) material was used as the working electrodes of the supercapacitor under a current density of 1 A/g and 3 A/g, they exhibited a specific capacitance of 2015 F/g and 1218.9 F/g, respectively. This capacitance value is 2.62 times higher than that of the structure without modification with a graphene layer. The capacitance value remains at 99.2% even after 1000 consecutive charge and discharge cycles at a current density of 20 A/g. This value also improved compared to the structure without graphene layer modification (94.7%). Full article

Supercapacitors (SCs) are widely used in energy storage devices due to their superior power density and long cycle lifetime. However, the limited energy densities of SCs hinder their industrial application to a great extent. In this study, we present a new combination of metallic phosphide–carbon composites, synthesized by directly carbonizing (Ni_1−xCo_x)₅TiO₇ nanowires via thermal chemical vapor deposition (TCVD) technology. The new method uses one-dimensional (1D) (Ni_1−xCo_x)TiO₇ nanowires as precursors and supporters for the in situ growth of intertwined porous CNF microspheres. These 1D nanowires undergo microstructure transformation, resulting in the formation of CoNiP nanoparticles, which act as excellent interconnected catalytic nanoparticles for the growth of porous 3D CNF microspheres. Benefiting from the synergistic effect of a unique 1D/3D structure, the agglomeration of nanoparticles can effectively be prevented. The resulting CNF microspheres exhibit an interconnected conductive matrix and provide a large specific surface area with abundant ion/charge transport channels. Consequently, at a scanning rate of 10 mV s⁻¹, its specific capacitance in 1.0 M Na₂SO₄ + 0.05 M Fe(CN)₆^3−/4− aqueous solution is as high as 311.7 mF cm⁻². Furthermore, the CoNiP@CNFs composite film-based symmetrical SCs show an ultrahigh energy density of 20.08 Wh kg⁻¹ at a power density of 7.20 kW kg⁻¹, along with outstanding cycling stability, with 87.2% capacity retention after 10,000 cycles in soluble redox electrolytes. This work provides a new strategy for designing and applying high-performance binary transition metal phosphide/carbon composites for next-generation energy storage devices. Full article

Micro/nano-heterostructure with subtle structural design is an effective strategy to reduce the self-aggregation of 2D structure and maintain a large specific surface area to achieve high-performance supercapacitors. Herein, we report a rationally designed micro/nano-heterostructure of complex ternary transition metal oxides (TMOs) by a two-step hydrothermal method. Microflake-assembled island-like CuCo₂O₄ frameworks and secondary inserted units of NiMoO₄ nanosheets endow CuCo₂O₄/NiMoO₄ composites with desired micro/nanostructure features. Three-dimensional architectures constructed from CuCo₂O₄ microflakes offer a robust skeleton to endure structural change during cycling and provide efficient and rapid pathways for ion and electron transport. Two-dimensional NiMoO₄ nanosheets possess numerous active sites and multi-access ion paths. Benefiting from above-mentioned advantages, the CuCo₂O₄/NiMoO₄ heterostructures exhibit superior pseudocapacitive performance with a high specific capacitance of 2350 F/g at 1 A/g as well as an excellent cycling stability of 91.5% over 5000 cycles. A solid-state asymmetric supercapacitor based on the CuCo₂O₄/NiMoO₄ electrode as a positive electrode and activated carbon as a negative electrode achieves a high energy density of 51.7 Wh/kg at a power density of 853.7 W/kg. These results indicate that the hybrid micro/nanostructured TMOs will be promising for high-performance supercapacitors. Full article

Cyclic 3d-4f molecular magnets have received considerable attention owing to their potential applications in high-density data storage and quantum information processing. As a rare example of ferromagnetic polynuclear Cr rings, {Cr₈Y₈} represents a valuable test bed to directly study the magnetic interaction between Cr³⁺ ions in large hexadecametallic {Cr₈Ln₈} (Ln = 4f metal) molecules. We have proposed a “single-J” model to approximate the low-temperature spin dynamics of {Cr₈Y₈} in our earlier study, while a zero-field splitting (ZFS) of the quantum levels was also suggested by the heat capacity data. In order to have a deeper understanding of the magnetism of {Cr₈Y₈}, it is necessary to verify the ZFS by means of high-resolution spectral methods and identify its origin. In this work, we present a high-frequency electron spin resonance (HF-ESR) study on the ZFS of {Cr₈Y₈}. The X-band ESR spectra consists of multi-peak structure, indicative of magnetic anisotropy that breaks the degeneracy between spin states in the absence of a magnetic field. HF-ESR spectra are collected to extract the ZFS parameters. We observed a sharp resonance peak due to the transitions between the S = 11 quantum levels and a broadband corresponding to a distribution of resonance peaks due to the ZFS of the S = 12 quantum levels. By analyzing HF-ESR spectra, we confirm the expected S = 12 ground state and determine its ZFS parameter D as −0.069 K, and, furthermore, we reproduce the spectra recorded at 154 GHz. The macrospin model proves to still be valid. The ZFS is attributed to the axial magnetic anisotropy, as found in some other Cr-based molecular wheels. The detailed HF-ESR investigation presented in this paper will benefit the studies on other {Cr₈Ln₈} wheels with magnetic Ln³⁺ ions and highlights the importance of the HF-ESR method as a high-resolution probe in determining the ZFS parameters with very small magnitude. Full article

A series of 18 lanthanide-containing 1D-coordination polymers ¹_∞[Ln₂(2–PyPzH)₄Cl₆], Ln = La, Nd, Sm, dinuclear polymorphic complexes α–, β–[Ln₂(2–PyPzH)₄Cl₆], Ln = Sm, Eu, Gd, α–[Tb₂(2–PyPzH)₄Cl₆], and [Gd₂(2–PyPzH)₃(2–PyPz)Cl₅], mononuclear complexes [Ce(2–PyPzH)₃Cl₃], [Ln(2–PyPzH)₂Cl₃], Ln = Tb, Dy, Ho, and Er, and salt-like complexes [Gd₃(2–PyPzH)₈Cl₈]Cl and [PyH][Tb(2–PyPzH)₂Cl₄] were obtained from the reaction of the respective lanthanide chloride with the 3–(2–pyridyl)pyrazole (2–PyPzH) ligand at different temperatures. An antenna effect through ligand-to-metal energy transfer was observed for several products, leading to the highest luminescence efficiency displayed by a quantum yield of 92% in [Tb(2–PyPzH)₂Cl₃]. The Ce³⁺ ion in the complex [Ce(2–PyPzH)₃Cl₃] exhibits a bright and orange 5d-based broadband emission with a maximum at around 600 nm, marking an example of a strong reduction of the 5d-excited states of Ce(III). The absorption spectroscopy shows ion-specific 4f–4f transitions, which can be assigned to Nd³⁺, Sm³⁺, Eu³⁺, Dy³⁺, Ho³⁺, and Er³⁺ in a wide spectral range from UV–VIS to the NIR region. Full article

Uranyl ions, {UO₂}ⁿ⁺ (n = 1, 2), display trans, strongly covalent, and chemically robust U-O multiple bonds, where 6d, 5f, and 6p orbitals play important roles. The synthesis of isoelectronic analogues of uranyl has been of interest for quite some time, mainly with the purpose of unveiling covalence and 5f-orbital participation in bonding. Significant advances have occurred in the last two decades, initially marked by the synthesis of uranium(VI) bis(imido) complexes, the first analogues with a {RNUNR}²⁺ core, later followed by the synthesis of unique trans-{EUO}²⁺ (E = S, Se) complexes, and recently highlighted by the synthesis of the first complexes featuring a linear {NUN} moiety. This review covers the synthesis, structure, bonding, and reactivity of uranium complexes containing a linear {EUE}ⁿ⁺ core (n = 0, 1, 2), isoelectronic to uranyl ions, {OUO}ⁿ⁺ (n = 1, 2), incorporating σ- and π-donating ligands that can engage in uranium–ligand multiple bonding, where oxygen may be replaced by heavier chalcogenido, imido, nitride, and carbene ligands, or by a transition metal. It focuses on synthetic methods of well-defined molecular uranium species in the condensed phase but also references gas-phase and low-temperature-matrix experiments, as well as computational studies that may lead to valuable insights. Full article