The rare element beryllium is primarily known for being a component of emeralds, aquamarines, and different precious stones. Nonetheless, in Nature Communications, an international group of scientists from the University of Bayreuth now reports on an unusual discovery: Below a pressure, 880,000 times the pressure of the Earth’s atmosphere – beryllium atoms in a phosphate crystal surround themselves with six neighboring atoms instead of the standard four. This crystal structure was theoretically envisioned five decades ago, but for the first time, it surely was solely throughout high-pressure experiments at the Deutsches Elektronensynchrotron (DESY) in Hamburg that it has now been noticed.
Dr. Maxim Bykov and Prof. Dr. Leonid Dubrovinsky from the Bavarian Geo-Institute were involved in the research on the part of the University of Bayreuth, as had been Dr. Anna Pakhomova and Georgios Aprilis from the Working Group for Material Physics and Technology under Excessive Conditions within the Laboratory for Crystallography.
Initially, science considered it not possible for beryllium atoms in crystals to have more than four neighboring atoms. This appeared to be incompatible with the crystal-chemical laws for a long time. “However about 50 years ago, theorists suggested that higher co-ordinations might be attainable, although these have stubbornly avoided experimental confirmation in inorganic compounds ever since,” reviews Dr. Anna Pakhomova, a beamline scientist at DESY and post-doctoral researcher.
High-pressure experiments at DESY’s — X-ray light source PETRA III have made empirical proof attainable. The researchers examined samples of a phosphate crystal hurlbutite – a rare mineral consisting of calcium, beryllium, phosphorus, and oxygen, which happens naturally on the Earth’s surface. Underneath normal environmental conditions, each beryllium atom only has four oxygen atoms as neighbors. At 700,000 instances atmospheric pressure, nonetheless, the crystal structure changes so basically that beryllium atoms acquire a fifth neighbor. In the meantime, an atmospheric pressure 880,000 times that at sea-level generates new structural changes that give rise to even a sixth neighbor.