Crystal structure and spectroscopic properties of new fluoride compound Na2K2NdF7

New fluoride compound Na₂K₂NdF₇ has been synthesised and obtained in the single crystal form by the Bridgman method. The crystal is cubic, space group , with lattice parameters a = 1.28283 (15) nm. In this structure Nd³⁺ ions reside in sites with C_4v symmetry. Judd–Ofelt analysis of optical absorption spectra revealed that radiative lifetime of the ⁴F_3/2 level of Nd³⁺ equals to 460 μs. Measured lifetime is 2.8 μs for Na₂K₂NdF₇ and 439 μs for Na₂K₂La_0.99Nd_0.01F₇, in agreement with the calculated value.