New family of Ruddlesden-Popper strontium niobium oxynitrides:: (SrO)(SrNbO2-xN)n (n = 1, 2)

The now family (SrO)(SrNbO2-xN)(n) (n = 1, n = 2) constitutes the first example of strontium niobium Ruddlesden-Popper oxynitrides and provides layered structures to obtain mixed valence niobium compounds with a variety of oxidation states and transport properties. They cystallize in the I4/mmm space group and show a range of anionic stoichiometries that modulate, together with the N/O ratio, the formal oxidation state of niobium and, therefore, the physical properties.