Perryite, (Ni,Fe) 16 PSi 5 , from the Mount Egerton aubrite: the first natural P-Si-ordered phosphide-silicide

[摘要] Perryite, natural Ni-silicide, is a minor but regular constituent of the metal phase in enstatite chondrite (aubrite) andenstatite chondrite meteorites. Its synthetic analog was shown to have promising catalytic properties. The first-timesolution of the crystal structure of natural perryite was completed on the material from the Mount Egerton aubrite.The mineral is trigonal, R¯3c, a = 6.6525(5), c = 37.998(5) Å, V = 1456.3(3) and Z = 6. The structure was refined toR1 = 0.0137 based on 457 independent observed reflections. The chemical formula obtained from the structure refinement,(Ni14.14Fe1.88)Σ16.02PSi5, agrees with that derived from the electron microprobe data, (Ni13.39Fe2.65Co0.01)Σ16.05P1.22Si4.74. Thisresearch showed that P and Si in perryite are ordered, resulting in the simplified formula (Ni,Fe)16PSi8, in contrast to thecurrently accepted variant (Ni,Fe)8(Si,P)3. The detailed results of EBSD study reveal previously unknown relationshipsbetween perryite, associated α-(Fe,Ni) metal (also known as kamacite) and schreibersite, (Fe,Ni)3P. Since enstatiticmeteorites represent the early stages of nebular accretion, our results demonstrate that the crystal-chemical factor couldaffect the differentiation of chemical elements upon the onset of the Solar System formation.

[学科分类] 自动化工程

[关键词] silicide;phosphide;aubrite;enstatite chondrite;meteorite;crystal structure