Structure refinement of Na2(Mg, Fe)6[(Ge, Fe)6O18]O2, a new aenigmatite-analog

Abstract

Abstract Single crystals of the compound Na2(Mg3.6 · Fe2.4)[(Ge5.6Fe0.4)O18]O2 have been grown from a Na2O–MoO3–V2O5 flux. The compound crystallizes in the triclinic P[unk] space group with a = 8.994 Å, b = 9.924 Å, c = 10.495 Å, α = 64.30°, β = 84.07°, γ = 65.87° and Z = 2. The refinement of its structure using single-crystal X-ray data shows that it is isostructural with the silicate minerals aenigmatite, Na2(Fe5Ti)(Si6O18)O2, and krinovite, Na2(Mg4Cr2)(Si6O18)O2.