The invention provides a light emitting diode device comprising a light emitting diode arranged on a substrate and a wavelength converting element. The wavelength converting element contains a luminescent material a Mn4+-activated fluoride compound having a garnet-type crystal structure. The Mn4+-activated fluoride compound preferably answers the general formula {A3}[B2-x-yMnxMgy] (Li3) F12-dOd, in which formula A stands for at least one element selected from the series consisting of Na+ and K+ and B stands for at least one element selected from the series consisting of Al3+, B3+, Sc3+, Fe3+, Cr3+, Ti4+ and In3+, and in which formula x ranges between 0.02 and 0.2, y ranges between 0.0 (and incl. 0.0) and 0.4 and d ranges between 0 (and incl. 0) and 1. As the luminescent materials of the described type and structure have high stability and low sensitivity towards humid environments, they can advantageously be used as in wavelength conversion elements of LED devices.