A new compound with brucite-like layers, K(0.72)Li(0.24)Sn(0.76)O(2), has been obtained two ways, via solid-state reactions: with a big excess of KOH and in a controllable atmosphere without water and carbon dioxide. It has P2 structure (in Hagenmuller's definition) as previously described for K(0.70)Zn(0.35)Sn(0.65)O(2). The latter compound has been repeatedly prepared using the new technique presented here. The structure was refined using powder X-ray profile analysis. Lithium cations are disordered with tin (+4) in the rigid part and introduce "acid" properties. Both types of potassium positions are split. The metastable P3 phase also appears in the K(2)O-Li(2)O-SnO(2) system. The sodium analogue Na(0.72)Li(0.24)Sn(0.76)O(2) with P2 structure has been prepared using an ion-exchange technique.