the formates due to the diversity of A-site ammonium and M-site transition metal cations which can be incorporated. A wide range of magnetic formates have now been investigated, with particular excitement found in the wide-range of non-collinear magnets, including the perovskite A[M(CHOO) 3 ] 6-8 and niccolite mixedmetal formates A{M[M (CHOO) 6 ]} .