High-temperature/high-pressure X-ray diffraction: Recent developments

We have developed two Merrill-Bassett diamond-anvil cells for specialized high-temperature uses. The first is constructed largely of rhenium to provide uniform, constant P and T on the order of 20 GPa at 1200 K for extended periods. The second is for single-crystal x-ray diffraction, but can be heated to 630 K at 20 GPa to grow single-crystal samples which cannot be produced at room temperature. With this cell, the crystal structure of ϵ-O2 was shown to be monoclinic with a = 3.649 A, b = 5.493 A, c = 7.701 A, and β = 116.11° at 19.7 GPa.