Low Temperature Phases of Na2Ti3Cl8 Revisited

Hänni, Nora; Frontzek, Matthias; Hauser, Jürg; Cheptiakov, Denis; Krämer, Karl (2017). Low Temperature Phases of Na2Ti3Cl8 Revisited. Zeitschrift für anorganische und allgemeine Chemie, 643(23), pp. 2063-2069. Wiley-VCH 10.1002/zaac.201700331

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The low temperature phases of Na2Ti3Cl8 and their phase transitions were investigated by powder neutron diffraction, heat capacity, and magnetic susceptibility measurements between 1.6 K and room temperature. Aside from the previously known high temperature α‐phase (R3m) and low temperature γ‐phase (R3m), a new intermediate temperature β‐phase was detected. It has a k = (1/4,1/4,0) superstructure and its molar volume and χT product are half way between the α‐ and γ‐phases. The β‐phase is observed between 210 K and 190 K on cooling in powder samples. Its formation is kinetically hindered in crystals. Upon heating the β→α transition occurs at 227 K. From the γ‐phase, a γ→α transitions is observed on heating. Only in heat capacity measurements, a shoulder of the peak indicates an intermediate formation of the β‐phase. Strong antiferromagnetic interactions between the Ti2+ ions result in the formation of triangular trimers (Ti3 clusters). In the γ‐phase all Ti2+ ions are part of trimers. For the β‐phase a structural model is proposed, where half of the Ti2+ ions form trimers. No long‐range magnetic order was observed in Na2Ti3Cl8 down to 1.6 K.

Item Type:

Journal Article (Original Article)

Division/Institute:

08 Faculty of Science > Departement of Chemistry and Biochemistry

UniBE Contributor:

Hänni, Nora; Hauser, Jürg and Krämer, Karl

Subjects:

500 Science > 530 Physics
500 Science > 540 Chemistry

ISSN:

0044-2313

Publisher:

Wiley-VCH

Funders:

[42] Schweizerischer Nationalfonds

Language:

English

Submitter:

Karl Krämer

Date Deposited:

13 Apr 2018 15:06

Last Modified:

31 Oct 2019 07:07

Publisher DOI:

10.1002/zaac.201700331

BORIS DOI:

10.7892/boris.110065

URI:

https://boris.unibe.ch/id/eprint/110065

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