The Li-bearing ferronigerite-2N1S occurs in the Xianghualing tin-polymetallic ore field, Linwu County, Hunan Province, Peoples Republic of China. It was found near the outer contact zone of the Laizhiling granite body and in the Middle-Upper Devonian carbonate rocks of the Qiziqiao Formation. Lithium-bearing ferronigerite-2N1S contains 0.83 wt.% Li2O. Its empirical formula is Al10.95 Sn1.62Fe1.30 Zn0.79 Mg0.66Li0.57Mn0.18Ca0.05 Ti0.03Si0.01 O22(OH)2. The structure for Li-bearing ferronigerite-2N1S was refined in space group P3̅m1, with a 5.7197(8), c 13.829(3) Å, V 391.81(11) Å3, to R1 = 0.0361. The refined formula of Li-bearing ferronigerite-2N1S is Al12.06Sn1.67Fe1.19Li0.83 Zn0.25O24H2. Both chemical analysis and structural refinement confirm the essential Li content in nigerite group minerals.
Instead of T4M12O22(OH)2, the simplified general formula for 2N1S polysomes in the nigerite and högbomite groups can be given as AxB16−xO22(OH)2, where x = ~3; A = Mg2+, Fe2+, Zn2+; B = Al3+, Sn4+, Ti4+, Li+, □.