crystal bar process
iodide process
van Arkel-de Boer process

Highly pure thorium can be extracted from its iodide with the crystal bar process.

Together with Anton Eduard van Arkel, de Boer developed a chemical transport reaction for titanium, zirconium, and hafnium known as the crystal bar process.

This Crystal bar process was developed by Anton Eduard van Arkel and Jan Hendrik de Boer in 1925.

Generally, the crystal bar process can be performed using any number of metals using whichever halogen or combination of halogens is most appropriate for that sort of transport mechanism, based on the reactivities involved.

The crystal bar process (also known as the Iodide Process), discovered by Anton Eduard van Arkel and Jan Hendrik de Boer in 1925, was the first industrial process for the commercial production of metallic zirconium.

Titanium of very high purity was made in small quantities when Anton Eduard van Arkel and Jan Hendrik de Boer discovered the iodide, or Crystal bar process, process in 1925, by reacting with iodine and decomposing the formed vapors over a hot filament to pure metal.

The crystal bar process (or "iodide process") was discovered by Anton Eduard van Arkel and Jan Hendrik de Boer in 1925 to produce high-purity metallic thorium.

In another method, called the van Arkel-de Boer process, the oxide was chemically converted to a halide (chloride, bromide or iodide) and then reduced in a vacuum with an electrically heated metallic filament:

The crystal bar process (also known as iodide process or the van Arkel-de Boer process) was developed by Anton Eduard van Arkel and Jan Hendrik de Boer in 1925.