Three previously unreported ternary phases of the type NixInP have been observed to be the primary reaction products of the Ni/InP reaction. The first phase, amorphous NixInP(x&bartil;2.7), forms at the Ni/InP interface by a solid‐state amorphization process at low temperatures (T≲200 °C). Amorphous NixInP crystallizes at ∼300 °C to form a hexagonal NixInP phase (a0=0.412 nm andc0=0.483 nm) with a similar composition. A third ternary phase with nominal composition Ni2InP (monoclinic,a0=0.681 nm,b0=0.529 nm,c0=1.280 nm, and &bgr;=95°) nucleates at higher temperatures and is the final reaction product. This final phase is stable at temperatures up to 500 °C in samples capped with SiO2.