Gmelin Handbook of Inorganic and Organometallic Chemistry - 8th Edition Element T-H Th. Thorium (Sys pdf epub mobi txt 电子书 下载 2026

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出版者:Springer

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页数:0

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出版时间:1986-07

价格:USD 779.00

装帧:Hardcover

isbn号码:9780387935324

丛书系列:

图书标签:

• Gmelin Handbook
• Inorganic Chemistry
• Organometallic Chemistry
• Thorium
• Reference Work
• Chemistry
• 8th Edition
• Supplement
• NR
• 44
• T-H

thorium: an overview of its chemistry and applications Thorium, a naturally occurring radioactive element with the atomic number 90, holds a unique position in the periodic table. Belonging to the actinide series, it is characterized by its high density, metallic luster, and remarkable radioactivity. While its presence on Earth is relatively scarce, thorium's intrinsic properties have sparked considerable scientific and industrial interest, leading to extensive research and development across various fields. Discovery and Early Research Thorium was discovered in 1828 by the Swedish chemist Jöns Jacob Berzelius, who named it after Thor, the Norse god of thunder. Initially, its radioactivity was not recognized, and it was primarily studied for its chemical properties. Early research focused on its extraction from monazite sands, a mineral rich in thorium and rare earth elements. The isolation and purification of pure thorium metal proved to be a challenging endeavor, but subsequent advancements in metallurgy and chemistry paved the way for its broader exploration. Physical and Chemical Properties Thorium is a silvery-white metal that tarnishes in moist air, forming a dark gray oxide layer. It is highly malleable and ductile, making it suitable for various manufacturing processes. Its melting point is exceptionally high, exceeding that of lead and aluminum, which contributes to its potential use in high-temperature applications. Chemically, thorium exhibits a valence of +4, forming stable compounds with oxygen, halogens, and other nonmetals. Its reactivity is moderate, and it can be dissolved in strong acids, releasing hydrogen gas. Radioactivity and Isotopes Thorium's radioactivity is a defining characteristic, stemming from its unstable isotopes. The most abundant naturally occurring isotope is thorium-232, which decays through a series of alpha and beta emissions, ultimately transforming into stable lead-208. This decay chain involves several intermediate radioactive isotopes, each with its own decay properties and half-life. The continuous decay of thorium-232 produces a significant amount of heat, a property that has been explored for nuclear energy applications. Occurrence and Extraction Thorium is found in small quantities in various minerals, with monazite being the primary source for its commercial extraction. Other thorium-containing minerals include thorite and thorianite. The extraction process typically involves crushing the ore, separating the thorium-bearing minerals, and then chemically processing them to isolate thorium compounds. These compounds are then further refined to obtain thorium metal or its oxides. Applications of Thorium Thorium's unique properties have led to its utilization in a diverse range of applications, spanning from traditional uses to emerging technologies: Gas Mantles: Historically, thorium dioxide (thoria) was a key component in incandescent gas mantles, where its ability to emit bright white light when heated made it invaluable for illumination. While modern lighting technologies have largely replaced gas mantles, this application played a significant role in the early industrial use of thorium. Welding Electrodes: Thorium-containing tungsten electrodes are widely used in gas tungsten arc welding (GTAW), also known as TIG welding. The addition of thorium to tungsten improves arc stability, increases current-carrying capacity, and reduces electrode erosion, leading to more efficient and cleaner welds. High-Temperature Alloys: Thorium's high melting point and resistance to oxidation make it a valuable additive in high-temperature alloys, particularly for aerospace and industrial applications where materials are subjected to extreme thermal conditions. It enhances the strength and creep resistance of these alloys. Lenses and Optics: Thorium dioxide has a high refractive index and low dispersion, making it suitable for manufacturing high-quality lenses for cameras, telescopes, and other optical instruments. While concerns about its radioactivity have led to a decline in its use in consumer-grade optics, it remains valuable in specialized applications. Nuclear Energy: Thorium holds significant promise as a nuclear fuel. Thorium-232 can be converted into fissile uranium-233 through neutron capture in a nuclear reactor. This fertile-fissile relationship allows for the potential development of thorium-based nuclear fuel cycles, which could offer several advantages over traditional uranium-based cycles, including reduced waste production and improved fuel efficiency. Thorium reactors are seen as a potential pathway to more sustainable and safer nuclear power. Catalysis: Thorium compounds, particularly thorium dioxide, have been explored for their catalytic properties in various chemical reactions. They can act as catalysts in processes such as the synthesis of ammonia and the dehydrogenation of hydrocarbons. Medical Applications: In the past, thorium compounds were used in some medical imaging procedures, such as barium meals, due to their radiopacity. However, concerns about their radioactivity have led to their discontinuation for such uses. Thorium in the Context of the Gmelin Handbook The Gmelin Handbook of Inorganic and Organometallic Chemistry, particularly the 8th Edition and its supplements focusing on Element T-H and Thorium, serves as a comprehensive repository of scientific knowledge regarding this element. These volumes meticulously detail the chemical, physical, and nuclear properties of thorium and its compounds. They document a vast array of research, covering synthesis, reaction mechanisms, thermodynamic data, spectroscopic characteristics, and structural information. The supplements dedicated to Thorium (System-Nr. 44) delve into specific aspects of its chemistry, such as the different oxidation states it exhibits, the formation of various inorganic and organometallic complexes, and its behavior in different chemical environments. Part A, for instance, likely covers the fundamental properties and basic compounds of thorium, while subsequent parts (B, C, D, E, etc.) would systematically explore more complex areas, including its compounds with specific elements, its organometallic chemistry, its occurrence in nature, and its extraction and purification methods. The detailed documentation within these volumes is crucial for researchers and chemists working with thorium, providing them with the foundational data and insights necessary for further investigation and application development. Safety and Environmental Considerations As a radioactive element, thorium requires careful handling and management. Its radioactive decay produces alpha, beta, and gamma radiation, which can be harmful if exposure limits are exceeded. Strict safety protocols are in place for its extraction, processing, and use to minimize radiation exposure to workers and the public. Furthermore, the long-lived radioactive isotopes present in thorium waste require secure storage and disposal to prevent environmental contamination. Future Prospects Despite the challenges associated with its radioactivity, thorium continues to be an element of significant interest. Its potential role in next-generation nuclear power systems, coupled with its applications in advanced materials and other specialized fields, ensures its ongoing relevance in scientific and technological advancements. Continued research into thorium chemistry and its safe and efficient utilization will be crucial in unlocking its full potential for the benefit of society.

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