thorium

The fundamental interest in actinide chemistry, particularly for the development of thorium-based materials, is experiencing a renaissance owing to the recent and rapidly growing attention to fuel cycle reactors, radiological daughters for nuclear medicine, and efficient nuclear stockpile development. Herein, we uncover fundamental principles of thorium chemistry on the example of Th-based extended structures such as metal-organic frameworks in comparison with the discrete systems and zirconium extended analogs, demonstrating remarkable over two-and-half-year chemical stability of Th-based frameworks as a function of metal node connectivity, amount of defects, and conformational linker rigidity through comprehensive spectroscopic and crystallographic analysis as well as theoretical modeling...

Presentation of baseline data on terrestrial gamma radiation (TGR) levels is crucial for assessing the annual effective dose received by the public due to natural radiation exposure. Cumulative doses from various sources can become significant, warranting a spatial understanding of TGR distribution. Few countries have comprehensively mapped TGR on a national scale, often facing challenges due to remote or inaccessible regions. This study investigated the influence of weathered soil groups on TGR dose rates in Sarawak-Borneo, Malaysia, to facilitate insights for TGR projection and isodose mapping...

Thorium-229 (229 Th) possesses an optical nuclear transition between the ground state (229g Th) and low-lying isomer (229m Th). A nuclear clock based on this nuclear-transition frequency is expected to surpass existing atomic clocks owing to its insusceptibility to surrounding fields1-5 . In contrast to other charge states, triply charged 229 Th (229 Th3+ ) is the most suitable for highly accurate nuclear clocks because it has closed electronic transitions that enable laser cooling, laser-induced fluorescence detection and state preparation of ions1,6-8 ...

Halide exchange of (Cp3tms )2 ThCl2 ( 1 ; Cp3tms = η5 -1,2,4-(Me3 Si)3 C5 H2 ) with Me3 SiI furnishes (Cp3tms )2 ThI2 ( 2 ), which is then reduced with potassium graphite (KC8 ) in the presence of 2,2'-bipyridine to give the thorium bipyridyl metallocene (Cp3tms )2 Th(bipy) ( 3 ) in good yield. Complex 3 was fully characterized and readily reacted with various small molecules. For example, 3 may serve as a synthetic equivalent for the (Cp3tms )2 Th(II) fragment when exposed to CuI, Ph2 S2 , organic azides, and CS2 ...

The use of radioisotopes in cancer therapy is becoming increasingly important. As a potential candidate for targeted alpha therapy, 230 U ( t 1/2 = 20.8 d), the decay daughter of 230 Pa ( t 1/2 = 17.4 d) is currently being investigated for cancer treatment. For radioisotopes to be used in biomedicine, they must be radiochemically pure and free from carrier interference. This can be challenging given their short half-life. Thus, radiological separation methods for harvesting isotopes for use in biomedicine must be simple, fast, and capable of obtaining the required purity levels...

The interaction between nonmetal and metal atoms has attracted great interest in the development of organometallic compounds and their promising applications. In this study, we explored the interaction between boron and thorium atoms, based on the stable B40 Th coordination compound, by employing density functional theory calculations. We elucidated the stability and geometries of the B40 Th coordination compound and revealed the electron transfer from the metal atom Th to B40 , which is evidenced by the natural bond orbital calculations...

Consumption of local and imported bottled water in Canada has greatly increased during the past three decades. While the presence of natural radioactivity is often overlooked when dealing with the water quality of these bottled products, it could contribute substantially to the uptake of radionuclides especially when sourced from regions with higher radioactivity levels compared to where it is consumed. In this study, the activity of several naturally occurring radionuclides (i.e., 210 Po, 226,228 Ra, 230,232 Th, 234,235,238 U) were measured in bottled water available in Québec, Canada after sample pretreatment and analysis by either radiometric or mass spectrometry approaches...

The reactions of two highly strained cyclopropenimine ligands L1H and L2H ( L1H = N 1 ,N 1 ,N 2 ,N 2 -tetraisopropyl-3-iminocycloprop-1-ene-1,2-diamine, L2H = N 1 ,N 1 ,N 2 ,N 2 -tetracyclohexyl-3-iminocycloprop-1-ene-1,2-diamine) with three thorium precursors Cp*2 ThCl2 , Cp*2 Th(Cl)(CH3 ), and Cp*2 Th(CH3 )2 were studied. At -20 °C, L1H and L2H react with Cp*2 ThCl2 to form Th1 ( Th1 = Cp*2 ThCl2 (L1H)) and Th2 ( Th2 = Cp*2 ThCl2 (L2H)), respectively, where the neutral ligand coordinates to the thorium metal center...

An N -aryloxide-amidine ligand ( 1 ), [ONNO] ligand, integrating phenoxide (PhO- ) and amidine ligands through methylene linkers, was employed in actinide chemistry. Upon reaction of the deprotonated ligand with ThCl4 (DME)2 in ether, the corresponding dimer complex 2 was obtained. Upon treatment of 2 with KCp* (Cp* = Cp(Me)5 ) in tetrahydrofuran, the corresponding {[ONNO]ThIV Cp*(LiCl)}2 ( 4 ) was obtained. In complex 2 , the two ArO- arms bonded from the same ligand to different ThIV centers. In contrast, both ArO- arms coordinated to the same metal center in 4 ...

The Kanyakumari coast is known to be a high background natural radiation area due to the placer deposits of heavy minerals such as ilmenite, monazite, and rutile. The Kanyakumari river sediments that could be the source of the elevated amounts of natural radionuclides in the coastal sands have been studied in this paper. The activity concentrations of primordial radionuclides 226 Ra, 232 Th, and 40 K were determined using high-purity germanium (HPGe) gamma-ray spectrometry. The mean activity concentrations of 226 Ra, 232 Th, and 40 K were found to be 75 Bq kg-1 , 565 Bq kg-1 , and 360 Bq kg-1 , respectively...

Ultra-low-radioactivity titanium alloys are promising materials for the manufacture of low-background detectors which are being developed for experiments in astroparticle physics and neutrino astrophysics. Structural titanium is manufactured on an industrial scale from titanium sponge. The ultra-low-background titanium sponge can be produced on an industrial scale with a contamination level of less than 1 mBq/kg of uranium and thorium isotopes. The pathways of contaminants during the industrial production of structural titanium were analyzed...

The recovery and recycling of metals that generate toxic ions in the environment is of particular importance, especially when these are tungsten and, in particular, thorium. The radioactive element thorium has unexpectedly accessible domestic applications (filaments of light bulbs and electronic tubes, welding electrodes, and working alloys containing aluminum and magnesium), which lead to its appearance in electrical and electronic waste from municipal waste management platforms. The current paper proposes the simultaneous recovery of waste containing tungsten and thorium from welding electrodes...

There is continued burgeoning interest in metal-metal multiple bonding to further our understanding of chemical bonding across the periodic table. However, although polar covalent metal-metal multiple bonding is well known for the d and p blocks, it is relatively underdeveloped for actinides. Homometallic examples are found in spectroscopic or fullerene-confined species, and heterometallic variants exhibiting a polar covalent σ bond supplemented by up to two dative π bonds are more prevalent. Hence, securing polar covalent actinide double and triple metal-metal bonds under normal experimental conditions has been a fundamental target...

Highly stable nitrogen-doped Graphene Quantum Dots (N-GQD) functionalized with Pamoic Acid (PA@N-GQD) are utilized for nanomolar detection of radioactive elements, Uranium (VI) and Thorium (IV), in pH ± 5.0. The absorption, fluorescence, crystalline nature, elemental composition, functional groups, and morphological state of as-prepared PA@N-GQD are evaluated by UV-visible absorption, photoluminescence, XRD, XPS, FTIR, HRTEM, FESEM, and AFM characterizations. The aqueous solution of PA@N-GQD is characterized by its spherical morphology, averaging 6...

Thorium-doped vacuum ultraviolet (VUV) transparent crystals is a promising candidate for establishing a solid-state nuclear clock. Here, we report the research results on high-concentration doping of 232 Th:CaF2 single crystals. The structures, defects, and VUV transmittance performances of highly doped Th:CaF2 crystals are investigated by theoretical and experimental methods. The defect configurations formed by Th and the charge compensation mechanism (Ca vacancy or interstitial F atoms) located at its first nearest neighbor position are mainly considered and studied...

Aromatic π-stacking is a weakly attractive, noncovalent interaction often found in biological macromolecules and synthetic supramolecular chemistry. The weak nondirectional nature of π-stacking can present challenges in the design of materials owing to their weak, nondirectional nature. However, when aromatic π-systems contain an unpaired electron, stronger attraction involving face-to-face π-orbital overlap is possible, resulting in covalent so-called "pancake" bonds. Two-electron, multicenter single pancake bonds are well known, whereas four-electron double pancake bonds are rare...

Roadside soil contamination is mostly caused by human-caused pollutant deposition. PTEs are among the many substances that are harmful for both humans and the environment. PTE concentrations in roadside soil in Chennai, southern India, have been determined in this study. To evaluate the seriousness of the threats, more environmental and geochemical indices have been applied. 83 soil samples have been obtained from the study regions and focusing on important roads. Elemental analysis has been analyzed with ED-XRF and sieve-filtered samples focused on PTEs such as arsenic, barium, cobalt, chromium, copper, iron, potassium, nickel, lead, thorium, titanium, zinc, and uranium...

The extraction of lead-212 (212 Pb) from radioactive thorium (Th) waste is immensely important, as it serves to mitigate environmental risks associated with radioactive waste and provides a vital source for medical isotopes. To economically extract 212 Pb from thorium, we synthesized a novel extractant known as 2,13-disulfonyldiethylamine dibenzo-18-crown-6 (DSADB18C6). We assessed its performance in isolating Pb(II) by employing stable lead and optimizing the parameters of the extraction system. The results showcased an exceptional ability to extract Pb(II) efficiently...

Soil samples from vegetable farmland in densely populated wards of Nepal were analyzed for natural radionuclide levels, employing a NaI(Tl) 3" [Formula: see text] 3" gamma detector. The study aimed to evaluate the causes of radiation risk, attributing it to soil contamination resulting from the rapid urbanization and concretization that followed the earthquake in 2015. The activity concentration of radium-226, thorium-232, and potassium-40 and the ranges observed are 2.080±0.084-33.675±1.356 Bq kg[Formula: see text], 17...

Contaminants, including naturally occurring radioactive material (NORM) of the 238-uranium and 232-thorium decay series, have been recognized as a global research priority to inform offshore petroleum infrastructure decommissioning decisions. This study aimed to characterize pipeline scale retrieved from a decommissioned subsea well tubular pipe through high-resolution elemental mapping and isotopic analysis. This was achieved by utilizing transmission electron microscopy, Synchrotron x-ray fluorescence, photostimulated luminescence autoradiography and Isotope Ratio Mass Spectrometry...