Study of the Na 2 O—MoO 3 System. Na 6 Mo 11 O 36 — a New Oxide with Anatase‐related Structure, and the Crystal Structures of Na 2 MoO 4

A new sodium molybdate, Na 6 Mo 11 O 36 , has been synthesized, and its crystal structure was determined by single crystal X‐ray diffraction (space group P‐1 ; a = 7.2722(6)Å, b = 22.376(1)Å, c = 9.6686(8)Å, α = 89.98(1)°, β = 112.12(1)°, γ = 90.29(1)°; Z = 2). The compound can be considered as a new structure type related to the anatase structure. Na 2 MoO 4 exists in four different modifications between room temperature and the melting point. The α‐phase is isostructural with spinel‐type Na 2 WO 4 , the γ‐phase with thenardite, Na 2 SO 4 (V), and the δ‐phase with Na 2 SO 4 (I). The diffraction patterns of β‐Na 2 MoO 4 are similar to those of the γ‐phase, but could not be indexed.