X-Ray Study of Low Temperature Phases in {N(CH3)4}2CoCl4

The space groups of seven phases of {N(CH 3 ) 4 } 2 CoCl 4 were determined by X-ray diffraction as P m c n (Z=4), incommensurate, P 2 1 c n (Z=20), incommensurate, P 112 1 / n (Z=12), P 12 1 / c 1(Z=4) and P 2 1 2 1 2 1 (Z=12), respectively in the order of decreasing temperature. These phases are characterized by the change of the cell dimension of the pseudo-hexagonal axis: c 0 , ∼5 c 0 , 5 c 0 , ∼5 c 0 , 3 c 0 , c 0 and 3 c 0 , respectively.