Abstract
The crystal structures of lomonosovite, ideally Na10Ti4(Si2O7)2(PO4)2 O4, a = 5.4170(7) Å, b = 7.1190(9) Å, c = 14.487(2) Å, α = 99.957(3)°, β = 96.711(3)°, γ = 90.360(3)°, V = 546.28(4) Å3, Dcalc. = 3.175 g cm-3, and murmanite, ideally Na4Ti4(Si2O7)2O4(H2O)4, a = 5.3875(6) Å, b = 7.0579(7) Å, c = 12.176(1) Å, α = 93.511(2)°, β = 107.943(4)°, γ = 90.093(2)°, V = 439.55(2) Å3, Dcalc. = 2.956 g.cm-3, from the Lovozero alkaline massif, Kola Peninsula, Russia, have been refined in the space group P