AM_Nenadkevichite Formula: K2.98 Na1.22 (Nb2.2 Ti1.8) Si8 O31.15 H13.2 Name: Nenadkevichite Unit cell: 14.692 14.164 7.859 90.0 117.87 90.0 , V=1445.74 Space group: C1M1 (8)

Rastsvetaeva R K , Tamazyan R A , Pushcharovsky D Y , Nadezhina T N , European Journal of Mineralogy , 6 (1994) p.503-509, Crystal structure and microtwinning of K-rich nenadkevichite, Note: Wat4 y-coordinate changed to reproduce reported bond lengths