Redetermination of the borax structure from laboratory X-ray data at 145 K

Area of Science:

• Crystallography
• Mineralogy
• Inorganic Chemistry

Background:

• Sodium tetraborate decahydrate, commonly known as borax, has a known crystal structure.
• Previous studies utilized X-ray and neutron diffraction to elucidate its structure.
• The structure consists of tetraborate anions and sodium octahedra forming chains.

Purpose of the Study:

• To refine the crystal structure of sodium tetraborate decahydrate.
• To precisely determine atomic bond distances, particularly O-H bonds.
• To compare findings with existing crystallographic data.

Main Methods:

• Single-crystal X-ray diffraction at 145 K.
• Structural analysis and refinement.
• Comparison with previous neutron diffraction data.

Main Results:

• The crystal structure was successfully redetermined at a low temperature (145 K).
• O-H bond distances were precisely measured.
• Average O-H bond distances were found to be shorter by 0.127(19) Å compared to neutron diffraction results.

Conclusions:

• The low-temperature redetermination provides more accurate O-H bond distance data for borax.
• This refinement enhances our understanding of the hydrogen bonding network in sodium tetraborate decahydrate.
• The findings contribute to the detailed crystallographic database of common minerals.