Abstract. fl Phase of (MnzCr)I2. Monoclinic B2/m. a = 7.441 (2), b=7.448 (2), c=3.978 (2)/~, 7=113"66 (2)°; Z=2. /t= 175.2 cm -~ (2=0-7107 ,A0. Final R=0.065. This phase is isotypic with monoclinic CrI2. A cooperative Jahn-Teller effect is found in (Mn, Cr)I2 as in CrI2, but with different values of the metal-iodine distance ratio.