Abstract:
The crystal structure of strontian potassicrichterite (Mg4.871Fe~+126Mno.052h5.049 (NaL425CaO.348SrO.297)r2.07Ko.873Si8.04802iOHhI5 - an unusual amphibole containing up to 3.7 wt.% SrO from the Murun alkaline massif, Eastern Siberia has been refined from X-ray powder diffraction data in monoclinic space group C2/m, with a = 10.0325(1) A, b = 17.977(1) A, c = 5.2698(1) A, and ~ = 104.70(lt. According to Mossbauer spectroscopy, nearly all iron occurs as Fe3+ in octahedral coordination. Rietveld refinement shows the Fe3+ to be ordered onto the M(2) site. Sr is completely ordered onto M(4).
