Experimental determinations and quantum-chemical calculations of the vibrational spectra of β-ZnB4O7 and β-CaB4O7

- Two high-pressure oxoborates with BO4- and OB3-groups were synthesized.
- They were investigated by FTIR and Raman spectroscopy.
- Ab initio quantum chemical calculations allowed almost complete band assignment.
- Standard borate classification schemes fail to describe the complex spectra.