High-pressure sapphire capillary cell for synchrotron single-crystal X-ray diffraction measurements to 1500 bar

A new sapphire capillary pressure cell for single-crystal X-ray diffraction measurements at moderate pressures (200-1500 bar; 1 bar = 100 kPa) has been developed and optimized for use on beamline I19 at Diamond Light Source. The three-component cell permits optical centring of the crystal and in situ pressure modification to a precision of 1 bar. Compression of hexamethylenetetramine and its deuterated analogue to 1000 bar was performed, showcasing the accuracy and precision of the measurements, and highlighting evidence of a geometric isotope effect.