ABSTRACT
The (NH 4 ,K)(Fe,Al) 2 (PO 4 ) 2 (OH)·2H 2 O multinary compound (mineral spheniscidite), which crystallizes in the monoclinic structure with the lattice parameters a = 975 ± 1, b = 963 ± 2, c = 970 ± 1 pm, and β = 102°34′ ± 7′ and a calculated density of 2.71 g cm−3, is formed in the Al–H–K–P–O–Fe–N system (Wilson and Bain 1986; Hawthorne et al. 1987).
