Chapter 30: Problem 2
Write short notes on (a) Chevrel phases (b) Zintl ions (c) Hexanuclear metal clusters
Short Answer
Expert verified
Chevrel phases are a group of compounds used in charge storage and conduction. Zintl ions are clusters of atoms with unique bonding formed when certain metals donate electrons to certain nonmetal elements. Hexanuclear metal clusters are complexes formed by self-assembly of six metal atoms often having unusual physical properties.
Step by step solution
01
Understanding Chevrel phases
Chevrel phases are a group of compounds typically of the formula M_xMo_6T_8 (where M is a metal, and T is S or Se) They possess unique properties which make them particularly useful in charge storage and conduction. They exhibit fast diffusion of multivalent ions which makes them good candidates for use in rechargeable batteries.
02
Understanding Zintl ions
Zintl ions are clusters of atoms formed when certain electropositive metals donate electrons to certain electronegative elements. These ions, named after Eduard Zintl, are found in salts and have properties of both ionic and covalent compounds. They take part in unique bonding situations where a metal atom donates one or more electrons to a nonmetal atom, resulting in the nonmetal atom having an electron configuration similar to a noble gas.
03
Understanding Hexanuclear metal clusters
Hexanuclear metal clusters are a class of cluster compounds formed by six metal atoms. These complexes are generated by self-assembly of the metal atoms and often have unusual physical properties. They are characterized by high symmetry and their electronic structures often result in interesting magnetic properties. They have been extensively studied as single-molecule magnets. Hexanuclear clusters are typically represented by the formula {M6(μ3-X)8} (where M is the metal and X represents a bridging ligand).
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Key Concepts
These are the key concepts you need to understand to accurately answer the question.
Chevrel phases
Chevrel phases, named after the scientist Michel Chevrel who first discovered them, are fascinating inorganic compounds generally represented by the formula \( M_xMo_6T_8 \) where \(M\) is usually a metal such as Pb or Sn, and \(T\) represents a chalcogen like sulfur or selenium. As components of advanced materials, they can significantly improve the efficiency of modern devices. Their structure consists of a cluster of six molybdenum atoms surrounded by eight chalcogen atoms, creating an electrically and thermally conductive framework.
These compounds stand out for their remarkable superconducting properties, which operate at relatively high temperatures when compared to other superconductors. With a unique capacity for hosting various metal ions, Chevrel phases can alter their electrical characteristics, making them highly valuable for applications such as high-performance rechargeable batteries, magnetic shielding, and even quantum computing.
In addition to their superconductivity, Chevrel phases display robust magnetic properties and are being researched for their potential use as thermoelectric materials that could convert waste heat into electrical energy.
These compounds stand out for their remarkable superconducting properties, which operate at relatively high temperatures when compared to other superconductors. With a unique capacity for hosting various metal ions, Chevrel phases can alter their electrical characteristics, making them highly valuable for applications such as high-performance rechargeable batteries, magnetic shielding, and even quantum computing.
In addition to their superconductivity, Chevrel phases display robust magnetic properties and are being researched for their potential use as thermoelectric materials that could convert waste heat into electrical energy.
Zintl ions
Zintl ions offer a unique perspective into the quantum realm of chemistry, where the standard rules of valence electron counting are bent. Named after the German chemist Eduard Zintl, these intriguing ions are crucial to understanding properties in a range of solid-state compounds.
Imagine electropositive metals, think of alkali or alkaline earth metals, which when teamed with more electronegative elements, say silicon or germanium, donate their valence electrons completely. This altruistic electron donation allows nonmetals to achieve a closed-shell electron configuration, akin to that of noble gases, resulting in the formation of Zintl ions. Typically found in intermetallic compounds, they exhibit a dual nature, manifesting characteristics of both metallic and covalent bonds.
These ions are not only intellectually stimulating but are also practical, helping to produce materials with novel electrical and thermal properties conducive for uses in thermoelectric devices or as precursors for nanomaterials synthesis.
Imagine electropositive metals, think of alkali or alkaline earth metals, which when teamed with more electronegative elements, say silicon or germanium, donate their valence electrons completely. This altruistic electron donation allows nonmetals to achieve a closed-shell electron configuration, akin to that of noble gases, resulting in the formation of Zintl ions. Typically found in intermetallic compounds, they exhibit a dual nature, manifesting characteristics of both metallic and covalent bonds.
These ions are not only intellectually stimulating but are also practical, helping to produce materials with novel electrical and thermal properties conducive for uses in thermoelectric devices or as precursors for nanomaterials synthesis.
Hexanuclear metal clusters
The realm of chemistry is sprinkled with entities as intricate as hexanuclear metal clusters. These complex structures, comprised of six metal atoms, come together to form a small, symmetric assembly often resembling a molecular polyhedron.
Characterized by their high level of symmetry and bonding intricacies, these clusters possess properties that can verge on the exotic. The general formula that represents these clusters is \( {M6(\mu3-X)8} \) where \(M\) stands for a transition metal and \(\mu3-X\) denotes a bridging ligand connecting the metal atoms. The highly delocalized electrons in these clusters contribute to magnetic characteristics that are fascinating for the study of molecular magnetism.
From magnetic resonance imaging (MRI) contrast agents to catalysts in industrial chemical reactions, hexanuclear clusters are becoming increasingly important. They can often act as single-molecule magnets (SMMs), which are promising for the future of high-density data storage and quantum computing, essentially functioning as the smallest units of magnetic memory.
Characterized by their high level of symmetry and bonding intricacies, these clusters possess properties that can verge on the exotic. The general formula that represents these clusters is \( {M6(\mu3-X)8} \) where \(M\) stands for a transition metal and \(\mu3-X\) denotes a bridging ligand connecting the metal atoms. The highly delocalized electrons in these clusters contribute to magnetic characteristics that are fascinating for the study of molecular magnetism.
From magnetic resonance imaging (MRI) contrast agents to catalysts in industrial chemical reactions, hexanuclear clusters are becoming increasingly important. They can often act as single-molecule magnets (SMMs), which are promising for the future of high-density data storage and quantum computing, essentially functioning as the smallest units of magnetic memory.
Electron configuration
The concept of electron configuration is pivotal for understanding the behavior of atoms in various chemical contexts, acting as a means to decipher the arrangement of electrons in an atom or molecule. By following the principles of quantum mechanics, one can determine the electron configuration by placing the electrons in atomic or molecular orbitals according to their energy levels.
The arrangement follows the well-known 'Aufbau principle', which fills the lowest energy levels first, leading to a specific order: 1s, 2s, 2p, 3s, 3p, and so forth. This fundamental framework is vital for comprehending how atoms will interact, bond, and react with each other because the outer electrons, or valence electrons, govern an atom's chemical properties.
Electron configurations are not just limited to single atoms but extend to more complex systems such as the Chevrel phases, Zintl ions, and hexanuclear clusters, influencing their unique electrical and magnetic properties.
The arrangement follows the well-known 'Aufbau principle', which fills the lowest energy levels first, leading to a specific order: 1s, 2s, 2p, 3s, 3p, and so forth. This fundamental framework is vital for comprehending how atoms will interact, bond, and react with each other because the outer electrons, or valence electrons, govern an atom's chemical properties.
Electron configurations are not just limited to single atoms but extend to more complex systems such as the Chevrel phases, Zintl ions, and hexanuclear clusters, influencing their unique electrical and magnetic properties.
Cluster compounds
Cluster compounds, marked by the assembly of three or more metal atoms surrounded by ligands, are a category of coordination compounds with mesmerizing geometry and peculiar chemical properties. Unlike their 'simpler' counterparts, these compounds boast high nuclearity, meaning they contain multiple metal atoms in close proximity.
The intriguing aspect of cluster compounds lies in their 'delocalized' bonding—a stark contrast to the ‘localized’ bonds in conventional compounds. This phenomenon results in a plethora of unique properties, from unusual oxidation states to intriguing reactivity patterns.
Cluster compounds are not just an academic curiosity. They have practical applications spanning catalysis, where their multiple reactive sites accelerate chemical transformations, to materials science, where they contribute to the creation of innovative materials such as non-linear optical compounds or molecular magnets.
The intriguing aspect of cluster compounds lies in their 'delocalized' bonding—a stark contrast to the ‘localized’ bonds in conventional compounds. This phenomenon results in a plethora of unique properties, from unusual oxidation states to intriguing reactivity patterns.
Cluster compounds are not just an academic curiosity. They have practical applications spanning catalysis, where their multiple reactive sites accelerate chemical transformations, to materials science, where they contribute to the creation of innovative materials such as non-linear optical compounds or molecular magnets.
Single-molecule magnets
Single-molecule magnets (SMMs) are a scintillating class of materials that, as their name indicates, exhibit magnetic properties at the scale of a single molecule. These compounds hold the potential to revolutionize data storage technology due to their ability to retain magnetic information at very small scales.
What sets SMMs apart is their ability to display magnetic hysteresis, a characteristic of bulk magnets, but at the molecular level. This feature makes them capable of functioning as the smallest possible bits in magnetic storage, hence providing avenues for miniaturization that are beyond the reach of conventional ferromagnetic materials. Its SMMs' unpaired electrons and their specific arrangement that grant them magnetic anisotropy, the directional dependence of their magnetic properties.
Research on SMMs is vibrant and unceasing, with hexanuclear metal clusters being a hotspot of investigation due to their potential as SMMs. Their application could go beyond storage, extending to quantum computing and enhanced MRI technologies, making it a field ripe with futuristic promise.
What sets SMMs apart is their ability to display magnetic hysteresis, a characteristic of bulk magnets, but at the molecular level. This feature makes them capable of functioning as the smallest possible bits in magnetic storage, hence providing avenues for miniaturization that are beyond the reach of conventional ferromagnetic materials. Its SMMs' unpaired electrons and their specific arrangement that grant them magnetic anisotropy, the directional dependence of their magnetic properties.
Research on SMMs is vibrant and unceasing, with hexanuclear metal clusters being a hotspot of investigation due to their potential as SMMs. Their application could go beyond storage, extending to quantum computing and enhanced MRI technologies, making it a field ripe with futuristic promise.
