PHOSPHIDE FROM METORITES - BARRINGERITE, A NEW IRON-NICKEL MINERAL

Schreibersite, (Fe,Ni)3P, and a higher phosphide, barringerite, occur in the Ollague pallasite. The composition of the higher phosphide, determined by electron probe microanalysis, is (Fe0.58Ni 0.42Co0.003)1.95P. It is hexagonal, with space group P62m and a=5.87±0.07 angstroms and c=3.44±0.04 angstroms. If we assume a primary origin, the new mineral indicates that troilite and Schreibersite crystallized at high temperatures. The occurrence of a higher phosphide in a pallasite indicates local nonequilibria within a group of meteorites that are remarkable for their overall degree of equilibrium crystallization.