Thioborates: potential nonlinear optical materials with rich structural chemistry

Area of Science:

• Materials Science
• Solid State Chemistry
• Crystallography

Background:

• Nonlinear optical (NLO) crystal materials are crucial for various applications.
• Metal chalcogenides and borates are common NLO material sources but have drawbacks.
• Thioborates offer a promising alternative, merging desirable properties of borates and sulfides.

Purpose of the Study:

• To review and categorize known thioborate compounds.
• To highlight the structural diversity and potential of thioborates.
• To identify research gaps in thioborate synthesis and NLO property exploration.

Main Methods:

• Literature review and classification of known thioborates.
• Analysis of structural motifs (0D to 3D) based on building units (BS3)3- and (BS4)5-.
• Summary of known crystallographic and preliminary property data.

Main Results:

• Thioborates exhibit diverse structures formed by corner-sharing BS3 and BS4 units.
• Nearly one-third of known thioborates are noncentrosymmetric, indicating NLO potential.
• Most thioborates' NLO properties remain largely unexplored.

Conclusions:

• Thioborates represent a promising class of materials for NLO applications.
• Further research is essential for targeted synthesis and property optimization.
• Investigating micro-mechanisms is key to unlocking their full potential.