Citation: Benabbas, A; Borel, M M; Grandin, A; Chardon, J; Leclaire, A; Raveau, B (1991). The niobium phosphate bronze $-beta-K~2~Na~2-x~Nb~8~P~5~O~34~, second form of the first member of the series (K~3~Nb~6~P~4~O~26~)~n~KNb~2~PO~8~. Journal of Solid State Chemistry, 91, pp. 323-330.
Formula: K2 Na1.73 Nb8 O34 P5
Chemical name:Potassium sodium niobium phosphate * - $-beta