Neutron powder diffraction study of A2BeF4 (A=K, Rb, Cs): Structure refinement and analysis of background

Arrangement of the 9- and 11-coordinated A cations (C-9 and C-11) and BeF4 groups for the A2BeF4 compounds (A=K, Rb and Cs). All of them have β-K2SO4 structures from room temperature to 1.5 K.