Exploration of Multi-Component Vanadium and Titanium Pnictides Using Flux Growth and Conventional High-Temperature Methods

Abstract

The flux growth method was successfully employed to synthesize millimeter-sized single crystals of the ternary barium vanadium pnictides Ba 5 V 12 As 19+x (x ≈ 0.02) and Ba 5 V 12 Sb 19+x (x ≈ 0.36), using molten Pb and Sb, respectively. Both compositions crystallize in space group P43m and adopt a structure similar to those of the barium titanium pnictides Ba 5 Ti 12 Pn 19+x (Pn = Sb, Bi), yet with a subtly different disorder, involving the pnictogen and barium atoms. Attempts to obtain an arsenide analog of Ba 5 Ti 12 Pn 19+x using a Pb flux technique yielded binary arsenides. High-temperature treatment of the elements Ba, Ti, and As in Nb or Ta tubes resulted in side reactions with the crucible materials and produced two isostructural compositions Ba 8 Ti 13−x M x As 21 (M = Nb, Ta; x ≈ 4), representing a new structure type. The latter structure displays fcc-type metal clusters comprised of statistically distributed Ti and M atoms (M = Nb, Ta) with multi-center and two-center bonding within the clusters, as suggested by our first-principle calculations.

Ba5Sb8: The Highest Homologue of the Family of Binary Semiconducting Barium Antimonides BanSb2n−2 (n ≥ 2)

“…The initial experiment that allowed for the serendipitous discovery of Ba 5 Sb 8 was designed with the aim to explore the Ba-Cr-Sb system for possible ternary compounds. Prior synthetic efforts with early transition elements, such as Ti and V, yielded several novel pnictides [18,19]. Thus, the progression from Group 4 and Group 5 elements to Group 6 elements constituted a logical extension of our experiments, particularly in light of the high solubility of Cr in excess of Sb at high temperatures and the existence of binary chromium antimonides, such as CrSb and CrSb 2 .…”

“…Ba 5 Sb 8 can be readily synthesized by employing a self-flux reaction with an excess of molten Sb. This method has been proven useful before and yielded several novel Zintl antimonides, such as CaV 3 Sb 4 and Ba 5 V 12 Sb 19 [18,19]. Approximately 3.0 g of the elemental mixture in a predetermined stoichiometric ratio of Ba:Cr:Sb = 2:1:3 was loaded into an alumina crucible.…”

Impact of zinc structural on the photovoltaic Properties of iron Pyrite

“…For our experimental work, we used the LMTO-ASA to analyze the impact of tiny concentrations of substitution Zn on the band gap of pyrite, this has been used by many researchers see Refs. [ 7 , [40] , [41] , [42] , [43] , [44] , [45] ].…”