Synthesis and crystal structure of acentric anhydrous beryllium carbonate Be(CO 3 ).

The anhydrous alkaline earth metal carbonate Be(CO ₃ ) 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 CO ₂ . It crystallizes in the acentric, trigonal space group P 3 ₁ 21 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(CO ₃ ) is characterized by the presence of isolated [CO ₃ ] ^2- -groups and BeO ₄ -tetrahedra. This is a new structure type and such a topology has not been observed in carbonates before. Be(CO ₃ ) can be recovered to ambient conditions and is not undergoing a phase transition during decompression.