Alkali Transition-Metal Molybdates: A Stepwise Approach to Geometrically Frustrated Systems.

Materials with triangular arrangements of transition metal ions are of great interest for their complex magnetism resulting from geometric frustration. This paper describes the stepwise formation of kagome lattices of open shell transition-metal ions from half-delta chains to delta/sawtooth chains, and finally kagome nets. The systems can be viewed as a testbed for magnetic studies since a variety of spin states can be introduced across the same structure type, and progress through increasing levels of structural complexity and dimensionality. The synthetic and structural development of this continuum is studied here in well-formed single crystals of A2 M3 (MoO4 )3 (OH)2 (A=K, Rb; M=Mn, Co), CsM2 (MoO4 )2 (OH) (M=Mn, Fe, Co, Zn), and KM3 (MoO4 )2 O(OH) (M=Mn).