TiNiSn

TiNiSn is a ternary intermetallic compound that belongs to the half-Heusler family. It crystallizes in the half-Heusler C1b structure, which consists of three interpenetrating face-centered cubic sublattices with one vacant site. In the ideal stoichiometric compound, Ti, Ni, and Sn occupy distinct lattice positions in a 1:1:1 ratio, yielding 18 valence electrons and typically semiconducting behavior.

Physical properties of TiNiSn include semiconducting transport with a band gap that is moderate in size and highly sensitive to synthesis conditions and doping. The material’s crystal structure contributes to relatively low lattice thermal conductivity, a characteristic that is advantageous for thermoelectric applications. The carrier type and concentration can be tuned by chemical substitution on Ti, Ni, or Sn sites, enabling both p-type and n-type conduction depending on the dopants or off-stoichiometry.

Applications of TiNiSn arise mainly in thermoelectric research and development. Half-Heusler compounds such as TiNiSn are studied for power generation and solid-state cooling at intermediate to high temperatures, typically in the range of several hundred to about one thousand kelvin. Realizing higher thermoelectric performance usually involves doping, nanostructuring, and precise control of phase purity to minimize parasitic phases and reduce thermal conductivity.

Synthesis and processing commonly employ arc melting of elemental Ti, Ni, and Sn followed by annealing to achieve the desired phase. High-quality samples may require extended annealing or crystal growth techniques to minimize secondary phases and deviations from stoichiometry.

TiNiSn is a representative member of the half-Heusler family, sharing the C1b structure and an 18-electron count that underpins its semiconducting behavior and potential for thermoelectric applications.