(Fe,Ni)2P allabogdanite can be an ambient pressure phase in iron meteorites
Konstantin D. Litasov, Tatyana B. Bekker, Nursultan E. Sagatov, Pavel N. Gavryushkin, P. G. Krinitsyn, К. Э. Купер
Abstract
Abstract An orthorhombic modification of (Fe,Ni) 2 P, allabogdanite, found in iron meteorites was considered to be thermodynamically stable at pressures above 8 GPa and temperatures of 1673 K according to the results of recent static high-pressure and high-temperature experiments. A hexagonal polymorphic modification of (Fe,Ni) 2 P, barringerite, was considered to be stable at ambient conditions. Experimental investigation through the solid-state synthesis supported by ab initio calculations was carried out to clarify the stability fields of (Fe,Ni) 2 P polymorphs. Both experimental and theoretical studies show that Fe 2 P-allabogdanite is a low-temperature phase stable at ambient conditions up to a temperature of at least 773 K and, therefore, is not necessarily associated with high pressures. This is consistent with the textural relationships of allabogdanite in iron meteorites.