Related Experiment Video
Updated: Jan 14, 2026
06:53
Author Spotlight: Magnetometric Characterization of Intermediates in the Solid-State Electrochemistry of Redox-Active Metal-Organic Frameworks
Published on: June 9, 2023
2.6K
Redox Reactions with Calcium-Metal Nanoparticles
Christian Ritschel1, Anja Appenzeller2, Radian Popescu3
1Institute of Inorganic Chemie, Karlsruhe Institute of Technology (KIT), Engesserstraße 15, D-76131, Karlsruhe, Germany.
Angewandte Chemie (International Ed. in English)
|October 25, 2025
Summary
Researchers synthesized novel calcium (Ca(0)) nanoparticles, significantly enhancing reactivity for chemical synthesis. These nanoparticles differ from Rieke calcium and enable the creation of new compounds, showcasing the potential of nanosized metals.
Area of Science:
- Inorganic Chemistry
- Materials Science
- Nanotechnology
Background:
- Bulk calcium metal exhibits low reactivity due to its surface area, solubility, and passivation.
- Nanosized calcium (Ca(0)) nanoparticles offer significantly enhanced reactivity compared to bulk metal.
- Existing methods for preparing reactive calcium, like Rieke calcium, have limitations.
Purpose of the Study:
- To synthesize and characterize novel, highly reactive Ca(0) nanoparticles.
- To demonstrate the enhanced reactivity of these nanoparticles in redox reactions.
- To explore the potential of Ca(0) nanoparticles for synthesizing new inorganic and organometallic compounds.
Main Methods:
- Synthesis of Ca(0) nanoparticles (5.4 ± 1.2 nm) via TMEDA-supported reduction of CaI2 with lithium naphthalenide in toluene.
- Redox reactions involving Ca(0) nanoparticles with metal precursors like [Cp2MoCl2] and [(Ph3P)AuCl].
- Characterization using electron microscopy, X-ray diffraction (single crystal and powder), IR, UV-Vis, NMR, EPR spectroscopy, and computation.
Main Results:
- Successful synthesis of Ca(0) nanoparticles, distinct from Rieke calcium.
- Formation of novel compounds: [{(DippNacNac)(thf)Ca}2(naph)] (1) featuring a naphthalenide dianion, [{(DippNacNac)(thf)CaMo(Cp)H}2(fulvalene)] (2) with unusual MoH→Ca dative bonding, and [Au9(PPh3)8](naph)(tmeda)0.5 (3) with a zerovalent gold Au9 cluster.
- Demonstration of Ca(0) nanoparticles' high reactivity in redox processes.
Conclusions:
- Nanosized alkaline-earth metals, specifically Ca(0) nanoparticles, possess significantly enhanced reactivity compared to their bulk counterparts.
- The synthesized Ca(0) nanoparticles are valuable reagents for novel chemical syntheses, leading to unique compounds.
- This work highlights the distinct properties and synthetic potential of nanosized metals in inorganic chemistry.
More Related Videos
Related Concept Videos
01:24Redox Reactions
58.2K
Oxidation-reduction or redox reactions involve the transfer of electrons from one molecule or atom to another. When an atom gains an electron, another atom must lose an electron, meaning oxidation and reduction must occur together. Since the redox occurs in pairs, the atom that gets oxidized is also called the reducing agent or reductant, and the atom that is reduced is also called the oxidizing agent or oxidant. A straightforward way to remember the definitions of oxidation and reduction is...
58.2K
01:27Redox Reactions
880
Redox reactions are vital biochemical processes that underpin energy metabolism in cells. These reactions involve the transfer of electrons between molecules, occurring in tandem as oxidation and reduction. Oxidation refers to the loss of electrons, while reduction denotes their gain. This coupling ensures the seamless flow of electrons through metabolic pathways. For example, in bacterial metabolism, glucose undergoes oxidation to carbon dioxide, while oxygen is simultaneously reduced to...
880
03:14Oxidation Numbers
42.1K
In redox reactions, the transfer of electrons occurs between reacting species. Electron transfer is described by a hypothetical number called the oxidation number (or oxidation state). It represents the effective charge of an atom or element, which is assigned using a set of rules.
42.1K
02:58Balancing Redox Equations
61.5K
Electrochemistry is the science involved in the interconversion of electrical and chemical reactions. Such reactions are called reduction-oxidation, or redox reactions. These important reactions are defined by changes in oxidation states for one or more reactant elements and include a subset of reactions involving the transfer of electrons between reactant species. Electrochemistry as a field has evolved to yield sufficient insights on the fundamental principles of redox chemistry and multiple...
61.5K
03:11Oxidation-Reduction Reactions
75.0K
Oxidation–Reduction Reactions
75.0K
01:23Redox Equilibria: Overview
1.5K
A reduction-oxidation reaction is commonly called a redox reaction. In a redox reaction, electrons are transferred from one species to another rather than being shared between or among atoms. The reducing agent or reductant is the species that loses electrons and gets oxidized in the process. The species that gains electrons and gets reduced in the process is the oxidizing agent or oxidant. Redox reactions are represented as two separate equations called half-reactions, where one equation...
1.5K