New Cr1-xTixSe solid solutions with NiAs-type structure: X-ray powder diffraction and emission spectroscopy studies

G. TIRAO; R. CARBONIO; J.P. BOLLETTA; J.M.DEPAOLI

PETRÓPOLIS

Congreso; XV Latin American Seminary of Analysis by X-ray Techniques ? SARX; 2016

The novel Cr1-xTixSe compounds have beensynthesized for x = 0, 0.05, 0.10 and 0.15. Although both CrSe and TiSe areindividually reported as NiAs-type phases, solid solutions in this system havenot been previously synthesized. Structural characterization was made using X-RayPowder Diffraction (XRD) data. All samples belong to the P63/mmc space groupand share the nickel arsenide (NiAs) structure type. Chromium and titanium are knownto have different oxidation states in selenide compounds, both varying between+2 and +4 oxidation states. In the case of study stoichiometry suggests a +2oxidation state for the metals. However, the NiAs structure presents a very shortcation-cation distance that can lead to some degree of bonding, affectingoxidation states. X-ray Emission Spectroscopy (XES) measurements were carriedout in order to study the oxidation state of chromium in these new compounds. Ahigh-resolution Kβ spectrum of a common chromium selenide is shown in Figure 1.By calculating the difference between the Kβ5and Kβ1,3 peak positions (DE) and comparing with appropriate standards, oxidation states can beinferred for each sample. All three substituted samples contain chromium in anaverage +2 oxidation state within experimental error. Additional samplecharacterization included resistivity measurements, which will also be discussedand complemented by the conclusions of the structural characterization as awhole.