AM_Fergusonite-(Y)_1 Formula: (Y.85 Yb.15) Nb O4 Name: Fergusonite-(Y) Unit cell: 5.05 10.89 5.27 90.0 94.5 90.0 , V=288.93 Space group: I121 (5)

Komkov A I , Soviet Physics Crystallography , 4 (1959) p.796-800, The structure of natural fergusonite, and of a polymorphic modification, Locality: Ural Mountains, Russia, Sample: annealed at T = 1000 C for t = 15 min