Ytterbium tris(hexafluoroacetylacetonate) Yb(C₅O₂HF₆)₃: The composition of overheated vapor and sublimation thermodynamics

• Published in: Russian journal of inorganic chemistry Vol. 56; no. 1; pp. 99 - 103
• Main Authors: Girichev, G. V, Rybkin, V. V, Tyunina, V. V, Krasnov, A. V, Tverdova, N. V, Kuz'mina, N. P, Zaitseva, I. G
• Format: Journal Article
• Language: English
• Published: Dordrecht Dordrecht : SP MAIK Nauka/Interperiodica 2011; SP MAIK Nauka/Interperiodica
• Subjects: Atomic properties; Chemistry; Chemistry and Materials Science; Dimers; Enthalpy; Inorganic Chemistry; Ion currents; Monomers; Oligomers; Physical Methods of Investigation; Sublimation; Ytterbium; Saturated Vapor; Extra Ligand; Ytterbium; Vapor Composition; Mass Spectrometric Determination
• ISSN: 0036-0236; 1531-8613
• DOI: 10.1134/S0036023611010086

A mass spectrometric study of the saturated vapor over ytterbium tris(hexafluoroacetylacetonate) Yb(hfa)₃ (hfa = CF₃-C(O)-CH-C(O)-CF₃) and of the vapor overheated up to the thermal decomposition temperature of the complex is presented. The vapor composition changes markedly with increasing temperature. At T ≈ 370 K, the mass spectrum of the vapor over Yb(hfa)₃ indicates the presence of ions containing one to three metal atoms. As the temperature is raised, the ion currents due to oligomer ions decrease. The oligomers are not detected at T > 440 K. The total decomposition temperature of Yb(hfa)₃ is 663(9) K. The second-law enthalpy of sublimation (ΔH s o (380 K)) is 134 ± 7 kJ/mol for the monomer and 138 ± 10 kJ/mol for the dimer. The enthalpy of dissociation of the dimer into monomer molecules is nearly equal to the enthalpy of sublimation of the monomer and dimer: ΔH dis(380 K) = 130 ± 15 kJ/mol.