Crystal structure of the commensurately modulated ζ phase of PAMC

The commensurately modulated ζ low-temperature phase of bis(propylammonium) tetrachloromanganate(II), [NH 3 (C 3 H 7 )] 2 MnCl 4 , has been determined at 8 K. a=7.437 (5), b=7.082 (5), c=13.096 (8) A, α=105.59 (1) o . Superspace group P2 1 /b(0β0)1s, with β=1/3, V=664.4, Z=2, D x =1.58 g cm -3 , Mo Kα radiation, λ=0.71069 A, μ=17.99 cm -1 , F(000)=326, wR(F)=0.064 for 1444 main reflections and wR(F)=0.089 for 248 satellite reflections. The modulation vector flips and locks into a commensurate value compared with the e phase, indicating a 'lock-in' and phase shift between adjacent modulated layers