Florenskyite, FeTiP, a new phosphide from the Kaidun meteorite

Florenskyite is a new phosphide species from the Kaidun chondritic meteorit e, which fell in South Yemen in 1980. Kaidun is a unique chondritic breccia containing a huge variety of fragments of different chondritic types. Flor enskyite was found as four dispersed grains with a maximum dimension of 14 mu m within a single mass of Fe-rich serpentine within one Kaidun clast. Fl orenskyite is associated with submicrometer-sized grains of pentlandite and small (up to 1.5 mu m in width) laths of a still uncharacterized Fe-Cr pho sphide. Florenskyite is creamy white in reflected light, and its luster is metallic. The average of three electron microprobe analyses gave (wt%) Fe 4 0.52, Ti 30.08, Ni 5.47, Cr 0.93, V 0.91, Co 0.60, P 21.69, Si 0.59, sum 10 0.79, corresponding to Fe-1.01(Ti0.87Ni0.13Cr0.03V0.02Co0.01)(1.06)(P0.97Si 0.03). Single-crystal structure analysis was performed on florenskyite usin g a Laue pattern collected from a multiple crystal by in-situ synchrotron X -ray diffraction. Florenskyite crystallizes in the space group Pnma, and ha s the anti-PbCl2 structure. Previously determined cell constants of synthet ic material [a = 6.007(1), b = 3.607(1), c = 6.897(1) Angstrom] were used i n the single-crystal data reduction. We used the POWD12 program to calculat e a powder XRD pattern; the 5 most intense reflections are d = 2.301 (l = 1 00), 2.188 (88), 2.307 (47), 1.938 (45), and 1.801 Angstrom (45). Florensky ite is only the fourth phosphide to be described from nature. Its paragenes is may be unique, and may be due to melting of a mineral assemblage includi ng Fe-Ni metal, schreibersite, daubreelite, osbornite, or heideite and subs equent crystallization of phosphides from the melt.