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 Im 3 ¯ m , with lattice parameters a = 1.28283 (15) nm. In this structure Nd3+ ions reside in sites with C4v symmetry. Judd–Ofelt analysis of optical absorption spectra revealed that radiative lifetime of the 4F3/2 level of Nd3+ equals to 460 μs. Measured lifetime is 2.8 μs for Na2K2NdF7 and 439 μs for Na2K2La0.99Nd0.01F7, in agreement with the calculated value.