Related Experiment Video
Updated: Jan 14, 2026
16:24
Controlling the Size, Shape and Stability of Supramolecular Polymers in Water
Published on: August 2, 2012
19.2K
Concentration-Dependent Structures and Ultrafast Dynamics within Aqueous BeF2: From Ion Complexes to Extended
Zhou Liang1, Peng Jiahui2, You Min3
1State Key Laboratory of Thorium Energy, Shanghai Institute of Applied Physics, Chinese Academy of Sciences, Shanghai 201800, China.
The Journal of Physical Chemistry. B
|October 18, 2025
Summary
Aqueous beryllium fluoride (BeF2) solutions form extended Be-F networks at high concentrations, significantly altering structural dynamics and viscosity. This network formation impacts separation and dehydration processes.
Area of Science:
- Chemistry
- Physical Chemistry
- Materials Science
Background:
- Understanding aqueous beryllium fluoride (BeF2) solutions is crucial for optimizing separation and dehydration processes.
- Salt concentration significantly influences the structural dynamics and properties of BeF2 solutions.
Purpose of the Study:
- To systematically investigate the concentration-dependent structures and dynamics of aqueous BeF2 solutions.
- To elucidate the molecular mechanisms linking microscopic coordination to macroscopic transport properties.
Main Methods:
- Nuclear magnetic resonance (NMR) spectroscopy
- Ultrafast spectroscopy
- Fourier transform infrared (FTIR) spectroscopy with a thiocyanate (SCN-) vibrational probe
- Polarization-selective pump-probe measurements
Main Results:
- Be2+ primarily exists as the tetrahedral complex [BeF2(H2O)2] in solution.
- An extended Be-F network forms at BeF2 concentrations exceeding 8.3 mol %.
- Increased salt concentration accelerates vibrational energy relaxation, suppresses rotational diffusion, and leads to non-Newtonian viscosity, with exponential increase above 8.3 mol %.
Conclusions:
- The study establishes a molecular mechanism linking microscopic coordination structures to macroscopic transport properties in BeF2 solutions.
- High BeF2 concentrations (>8.3 mol %) induce network formation, altering solution dynamics and viscosity beyond classical models.
- Findings advance the understanding of BeF2 solution behavior for improved separation and dehydration technologies.
Related Concept Videos
03:45Formation of Complex Ions
25.7K
A type of Lewis acid-base chemistry involves the formation of a complex ion (or a coordination complex) comprising a central atom, typically a transition metal cation, surrounded by ions or molecules called ligands. These ligands can be neutral molecules like H2O or NH3, or ions such as CN− or OH−. Often, the ligands act as Lewis bases, donating a pair of electrons to the central atom. These types of Lewis acid-base reactions are examples of a broad subdiscipline called coordination...
25.7K
01:23Complexation Equilibria: Overview
1.3K
Complexation reactions take place when dative or coordinate covalent bonds form between metal ions and ligands. The compounds formed in these reactions are called coordination compounds. The number of bonds formed between the metal ion and the ligands is called its coordination number. Generally, most metal ions in an aqueous solution are solvated by water molecules and thus exist as aqua complexes.
The equilibrium constant of the complexation reaction is represented as the formation constant...
The equilibrium constant of the complexation reaction is represented as the formation constant...
1.3K
02:16Resonance and Hybrid Structures
25.0K
According to the theory of resonance, if two or more Lewis structures with the same arrangement of atoms can be written for a molecule, ion, or radical, the actual distribution of electrons is an average of that shown by the various Lewis structures.
Resonance Structures and Resonance Hybrids
The Lewis structure of a nitrite anion (NO2−) may actually be drawn in two different ways, distinguished by the locations of the N–O and N=O bonds.
Resonance Structures and Resonance Hybrids
The Lewis structure of a nitrite anion (NO2−) may actually be drawn in two different ways, distinguished by the locations of the N–O and N=O bonds.
25.0K
01:09Complexation Equilibria: Factors Influencing Stability of Complexes
788
In complexation reactions, metal cations are the electron pair acceptors, and the ligands are the electron pair donors. The stability of the metal complexes depends primarily on the complexing ability of the central metal ion and the nature of the ligands. Generally, the complexing ability of the metal ion depends on the size and charge of the ion. As the metal ion size increases, the stability of the metal complexes decreases, provided that the valency of the metal ion and the ligands remain...
788
02:42Valence Bond Theory
11.2K
Coordination compounds and complexes exhibit different colors, geometries, and magnetic behavior, depending on the metal atom/ion and ligands from which they are composed. In an attempt to explain the bonding and structure of coordination complexes, Linus Pauling proposed the valence bond theory, or VBT, using the concepts of hybridization and the overlapping of the atomic orbitals. According to VBT, the central metal atom or ion (Lewis acid) hybridizes to provide empty orbitals of suitable...
11.2K
02:58Crystal Field Theory - Octahedral Complexes
30.6K
Crystal Field Theory
To explain the observed behavior of transition metal complexes (such as colors), a model involving electrostatic interactions between the electrons from the ligands and the electrons in the unhybridized d orbitals of the central metal atom has been developed. This electrostatic model is crystal field theory (CFT). It helps to understand, interpret, and predict the colors, magnetic behavior, and some structures of coordination compounds of transition metals.
CFT focuses on...
To explain the observed behavior of transition metal complexes (such as colors), a model involving electrostatic interactions between the electrons from the ligands and the electrons in the unhybridized d orbitals of the central metal atom has been developed. This electrostatic model is crystal field theory (CFT). It helps to understand, interpret, and predict the colors, magnetic behavior, and some structures of coordination compounds of transition metals.
CFT focuses on...
30.6K