Synthesis and crystal structure of acentric anhydrous beryllium carbonate Be(CO₃)

The anhydrous alkaline earth metal carbonate Be(CO₃) was synthesized in a laser-heated diamond anvil cell at moderate pressures and temperatures (20(2) GPa and 1500(200) K) by a reaction of BeO with CO₂. It crystallizes in the acentric, trigonal space group P3₁21 with Z = 3. The crystal structure was obtained from synchrotron single crystal X-ray diffraction data and confirmed by density functional theory-based calculations in combination with Raman spectroscopy. Second harmonic generation measurements were employed to verify the acentric space group symmetry. The crystal structure of Be(CO₃) is characterized by the presence of isolated [CO₃]^2--groups and BeO₄-tetrahedra. This is a new structure type and such a topology has not been observed in carbonates before. Be(CO₃) can be recovered to ambient conditions and is not undergoing a phase transition during decompression.