Bond-valence parameters for ammonium-anion interactions

Area of Science:

• Solid-state chemistry
• Crystallography
• Chemical bonding

Background:

• The bond-valence model is crucial for understanding crystal structures.
• Accurate bond-valence parameters are needed for predicting and analyzing chemical bonding in solids.

Purpose of the Study:

• To calculate bond-valence parameters (r0 and b) for ammonium ion (NH4+) interactions with common anions (O, F, Cl).
• To extend existing methods for parameter calculation, allowing for environment-specific analysis and data filtering.

Main Methods:

• Utilized data from the Cambridge Structural Database (CSD) and Inorganic Crystal Structural Database (ICSD).
• Analyzed NH4+...X contact lengths across diverse structural environments.
• Developed an extended procedure for calculating r0 and b parameters, incorporating data quality criteria.

Main Results:

• Successfully calculated bond-valence parameters r0 and b for NH4+-O, NH4+-F, and NH4+-Cl interactions.
• Obtained parameters show excellent agreement with predictions from the established bond-valence model.
• The refined methodology enables reliable parameter determination from a practical range of interaction distances.

Conclusions:

• The calculated bond-valence parameters are highly applicable to ammonium ion interactions.
• The study validates and refines the bond-valence model for describing bonding involving the ammonium cation.
• This work provides valuable parameters for further crystallographic and chemical bonding studies.