The Predicted Structures of the New Pnictides HfMQ in Contrast to ZrMQ (M = Ti, V; Q = P, As)



The new pnictides HfTiP, HfTiAs and HfVAs have been prepared through arc-melting. These arsenides form the predicted structures with (distorted) TiAs4 and VAs4 tetrahedra, while the structures of both Zr analogs (ZrTiAs and ZrVAs) are comprised of TiAs4 and VAs4 square planes, respectively. These differences stem from significant differences in the metal atom substructures. On the other hand, HfTiP and ZrTiP are isostructural. These variations were predicted by utilizing a structure map for metal-rich pnictides and chalcogenides M2Q (M = valence-electron poor transition metal, Q = pnicogen or chalcogen) presented in the year 2000. The HfMQ structure is stabilized by strong Hf−Q, M−Q and M−M bonds, and to a minor extent by Hf−Hf and Hf−M bonding interactions. All three new Hf1−δM1+δQ phases exhibit significant phase ranges. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004)