GdBO3 and YBO3 crystals under compression

High-pressure X-ray diffraction studies on nanocrystals of the GdBO3 and YBO3 rare-earth orthoborates are herein reported up to 17.4(2) 13.4(2) GPa respectively. The subsequent determination room-temperature pressure-volume equations state is presented discussed in context contemporary publications which contradict findings this work. In particular, isothermal bulk moduli found be 170(13) 163(13) respectively, almost 50% smaller than recent findings. Our experimental results provide an accurate revision high-pressure compressibility behaviour consistent with known systematics isomorphic borates previous ab initio calculations. Finally, we discuss how experimental/analytical errors could have led unreliable conclusions elsewhere.