Dimolybdenum tetratrimethylacetate (tetrapivalate) and tetratrifluoroacetate are synthesized, and their evaporation is studied by the Knudsen effusion method with mass spectral analysis of the gas phase. The standard enthalpies of formation of crystalline and gaseous Мо2(СF3COO)4 are estimated for the first time by the study of dissociative ionization. The solid-phase reactions of silver pivalate (CН3)3СCOOAg with molybdenum are studied by thermography (TG), differential scanning calorimetry (DSC), and mass spectrometry. The reaction in a temperature range of 410–480 K affords molybdenum oxopivalate МоО2Piv2. The obtained experimental data make it possible to estimate the standard enthalpy of formation of this compound: Δ_fH_298^^∘ (МоО2Рiv2, cr) = –1476 kJ/mol.

Dimolybdenum tetratrimethylacetate (tetrapivalate) and tetratrifluoroacetate are synthesized, and their evaporation is studied by the Knudsen effusion method with mass spectral analysis of the gas phase. The standard enthalpies of formation of crystalline and gaseous Мо2(СF3COO)4 are estimated for the first time by the study of dissociative ionization. The solid-phase reactions of silver pivalate (CН3)3СCOOAg with molybdenum are studied by thermography (TG), differential scanning calorimetry (DSC), and mass spectrometry. The reaction in a temperature range of 410–480 K affords molybdenum oxopivalate МоО2Piv2. The obtained experimental data make it possible to estimate the standard enthalpy of formation of this compound: ΔfH°298 (МоО2Рiv2, cr) = –1476 kJ/mol.

The [Сu–C6F11COOAg] system has been studied by thermogravimetry, differential scanning calorimetry, and mass spectrometry methods. It has been found that a solid-phase exchange reaction to form C6F11COOCu and silver occurs in the condensed phase of the system in a temperature range of 370–445 K. It has been found that the enthalpy of this reaction is Δr H_298.15^0 = −17.5 ± 4.0 kJ/mol and the standard enthalpy of formation of a crystalline copper complex is Δf H_298.15^0 = −2769 ± 25 kJ/mol. The sublimation of the copper complex is accompanied by the transition of dimeric (C6F11COOCu)2 molecules (Δs H_T^0 = 134.4 ± 7.2 kJ/mol) and a small amount of tetrameric (C6F11COOCu)4 molecules into the gas phase. The standard enthalpy of formation of a dimer complex in the gas phase of Δf H_298.15^0 = −5404 ± 26 kJ/mol has been calculated. The possibility of occurrence of the exothermic interaction of copper perfluorocyclohexanoate with metallic copper in the condensed phase has been explored.

Anhydrous dimolybdenum perfluorotetrabenzoate Мо2(ООСС6F5)4 (I) and silver perfluorocyclohexanoate AgOOCC6F11 (II) are synthesized for the first time. Complex I is synthesized by the transcarboxylation of dimolybdenum tetraacetate with pentafluorobenzoic acid. Compound II is synthesized from freshly prepared silver oxide and perfluorocyclohexanoic acid. The evaporation of the complexes is studied by the Knudsen method with mass spectral analysis of the gas phase. The sublimation of Мо2(ООСС6F5)4 is congruent. The enthalpy of sublimation and the equation of the temperature dependence of the vapor pressure are found. The evaporation of AgOOCC6F11 is accompanied by the complete thermal decomposition with the formation of Ag(s) and mainly С6F12, С6F10, and CO2 molecules. The standard enthalpies of thermal decomposition (∆rH°298.15(5) = 439.5 Ѓ} 16.4 kJ/mol, (∆rH°298.15(6) = 325.2 Ѓ} 14.0 kJ/mol) and formation of the silver complex ((∆rH°298.15(AgOOCC6F11, c) = –2751.0 Ѓ} 24.4 kJ/mol) are determined.

The thermodynamic properties of alkali metal pivalates (CH3)3CCOOM, where M = Li, Na, K, Rb, Cs, were studied by mass spectrometry, thermogravimetric analysis, and differential scanning calorimetry. The sublimation of the compounds was determined to be congruent. The saturated vapor contains oligomeric forms MnPivn (n = 1–6), which are dominated by dimeric and tetrameric molecules in the case of Na and K pivalates and by monomeric and dimeric molecules in the case of Rb and Cs pivalates. The partial pressures of the main components of the gas phase, their temperature dependence, and their standard enthalpies of sublimation were calculated. The enthalpies of dissociation of dimeric and tetrameric molecules were found. The standard enthalpies of formation MPiv(solid) and MPiv(gas) were estimated.

— The thermodynamic properties of alkali metal pivalates (CH 3 ) 3 CCOOM, where M = Li, Na, K, Rb, Cs, were studied by mass spectrometry, thermogravimetric analysis, and differential scanning calorimetry. The sublimation of the compounds was determined to be congruent. The saturated vapor contains oligomeric forms M n Piv n ( n = 1–6), which are dominated by dimeric and tetrameric molecules in the case of Na and K pivalates and by monomeric and dimeric molecules in the case of Rb and Cs pivalates. The partial pressures of the main components of the gas phase, their temperature dependence, and their standard enthalpies of sublimation were calculated. The enthalpies of dissociation of dimeric and tetrameric molecules were found. The standard enthalpies of formation MPiv(solid) and MPiv(gas) were estimated.

The ionic compound [Co(OC 5 H 2 N(NO 2 ) 2 ) 4 ]((C 2 H 5 ) 3 NH) 2 ( I ) was synthesized by the reaction of CoCl 2 ·6H 2 O with 2-hydroxy-3,5-dinitropyridine in acetonitrile in the presence of triethylamine as a deprotonating agent. The structure of compound I was studied by X-ray diffraction (CCDC no. 2196071) and thermodynamic characteristics of I were determined.

Solid-phase reactions of silver trifluoroacetate CF3COOAg with copper, indium, and zinc are studied by thermogravimetry, differential scanning calorimetry, and mass spectrometry. In a temperature range of 358–428 K, the reactions are found to afford trifluoroacetates of these metals without mass loss of the weighed samples. The obtained experimental data make it possible to calculate the enthalpy of formation of copper trifluoroacetate Δ_fH_298^^∘ (CF3СООСu, cr) = –1020.5 ± 18.0 kJ/mol.

A new trinuclear triangular cobalt complex (NMe 4 )[Co 3 (μ 3 F)(TFA) 6 (Py) 3 ] ( I ) is synthesized by crystallization from a methanol solution. The crystal structure of complex I is solved by single-crystal X-ray diffraction analysis (CIF file CCDC no. 2151075). The Knudsen effusion method combined with mass spectral analysis of gaseous vaporization products shows that the heating of complex I under reduced pressure results in the removal of (CH 3 ) 4 NF as (CH 3 ) 3 N and CH 3 F and of pyridine to form anhydrous cobalt trifluoroacetate Co(CF 3 COO) 2 , which sublimes on further heating to the monomer and dimer. The decomposition of Co(CF 3 COO) 2 with the formation of CoF 2 and release of CO 2 and COF 2 occurs along with sublimation. Experiments on the iso- and polythermal vaporization makes it possible to calculate the partial pressures of the major gaseous products, to determine the standard enthalpies of sublimation of the monomer (137.9 ± 12.2 kJ/mol) and dimer (147.0 ± 21.6 kJ/mol) in a temperature range of 460–540 K, and to find the enthalpy of dissociation of the dimer (128.8 ± 25.8 kJ/mol). The study of the thermal stability of complex I in an argon flow ( p = 1 atm) by gravimetry combined with mass spectral analysis of gaseous products confirms the three-stage decomposition of complex I . Unlike heating in vacuo, no sublimation of Co(TFA) 2 is observed under these conditions, and the decomposition of Co(TFA) 2 results in the formation of CoF 2 and is accompanied by the release of gaseous (CH 3 ) 3 N, CH 3 F, Py, CO, CO 2 , CHF 3 , СF 3 COF, (CF 3 CO) 2 O, CF 3 COCF 3 , and C 2 F 4 . The presence of moisture and oxygen traces in argon leads to a decrease in the content of easily hydrolyzed products and formation of the oxidation and hydrolysis products: H 2 O, HF, and CF 3 COOH.

The thermodynamic characteristics of silver perfluorobenzoates C6F5COOAg·0.5C6F5COOH and C6F5COOAg were studied by thermogravimetry, differential scanning calorimetry, and mass spectrometry. It was found that vaporization of these compounds occurs incongruently to give metallic silver and C6F5COOH, C12F10, CO2, and C18F14 molecules. Using the 2nd and 3rd laws of thermodynamics, the standard enthalpy of formation of silver perfluorobenzoate was found to be $${{\Delta }_{{\text{f}}}}H_{{{\text{298}}}}^{^\circ }$$ (C6F5COOAg, cr) = –1195.6 ± 15.7 kJ/mol and the standard enthalpy of formation of the pentafluorobenzoic acid radical was estimated to be $${{\Delta }_{{\text{f}}}}H_{{{\text{298}}.{\text{15}}}}^{^\circ }$$ (C6F5COO•, cr) = –878.6 ± 25.0 kJ/mol.

The reaction of zinc pentafluorobenzoate [Zn(H2O)(C6F5COO)2]n with a pyridine excess (Py, ratio Zn : Py = 1 : 4) affords crystals of complex [Zn2(H2O)(C6F5COO)4(Py)4] (I). The crystal packing of complex I is stabilized by numerous intra- and intermolecular interactions π…π, O…H, F…π, C–H…F, and С–H…O. The compound is characterized by the data of X-ray diffraction (XRD) (CIF file ССDС no. 2157445), IR spectroscopy, C,H,N elemental analysis, and phase XRD analysis. The vaporization of [Zn2(H2O)(C6F5COO)4(Py)4] is studied by the Knudsen effusion method with mass spectral analysis of the gas phase. This process is found to proceed in three stages with the consecutive transition of pyridine molecules to the vapor, partial hydrolysis, and congruent sublimation of zinc pentafluorobenzoate to form free molecules of Zn(C6F5)2 and СО2. The absolute partial pressures of saturated vapor and standard enthalpies of formation are calculated: $${{\Delta }_{f}}H_{{298}}^{^\circ }$$ (Zn(C6F5COO)2, s) ≤ –2634.1 ± 32.2 kJ/mol and $${{\Delta }_{f}}H_{{298}}^{^\circ }$$ (Zn(С6F5)2, g) ≤ –1422.6 ± 31.3 kJ/mol.

The reaction of zinc pentafluorobenzoate [Zn(H 2 O)(C 6 F 5 COO) 2 ] n with a pyridine excess (Py, ratio Zn : Py = 1 : 4) affords crystals of complex [Zn 2 (H 2 O)(C 6 F 5 COO) 4 (Py) 4 ] ( I ). The crystal packing of complex I is stabilized by numerous intra- and intermolecular interactions π…π, O…H, F…π, C–H…F, and С–H…O. The compound is characterized by the data of X-ray diffraction (XRD) (CIF file ССDС no. 2157445), IR spectroscopy, C,H,N elemental analysis, and phase XRD analysis. The vaporization of [Zn 2 (H 2 O)(C 6 F 5 COO) 4 (Py) 4 ] is studied by the Knudsen effusion method with mass spectral analysis of the gas phase. This process is found to proceed in three stages with the consecutive transition of pyridine molecules to the vapor, partial hydrolysis, and congruent sublimation of zinc pentafluorobenzoate to form free molecules of Zn(C 6 F 5 ) 2 and СО 2 . The absolute partial pressures of saturated vapor and standard enthalpies of formation are calculated: Δ_fH_298^^∘ (Zn(C 6 F 5 COO) 2 , s) ≤ –2634.1 ± 32.2 kJ/mol and Δ_fH_298^^∘ (Zn(С 6 F 5 ) 2 , g) ≤ –1422.6 ± 31.3 kJ/mol.

Detailed analysis is carried out for the set of experimental data, including those given in most recent publications, on the gas-phase and heterogeneous equilibria of reactions involving lower chromium fluorides. The causes for discrepancies between the same thermodynamic characteristics of compounds obtained in various studies are considered. The results of the analysis are presented as corrected enthalpies of formation of crystalline and gaseous compounds: ΔfH°(CrF, g, 0) = –42.5 ± 15.1 kJ/mol, ΔfH°(CrF2, cr, 298.15 K) = –780.7 ± 2.5 kJ/mol, ΔfH°(CrF2, g, 0) = –454.7 ± 4.6 kJ/mol, ΔfH°(CrF3, cr, 298.15 K) = –1146.7 ± 4.2 kJ/mol, and ΔfH°(CrF3, g, 0) = –799.9 ± 12.1 kJ/mol. The possibility of formation of crystalline Cr2F5 upon reduction of CrF3(cr) was confirmed.

The vaporization of lithium pivalate (CH3)3CCOOLi (LiPiv) was studied by the Knudsen effusion method with the mass spectral analysis of the gas phase. The saturated vapor consisted of polynuclear molecules (LiPiv)n, dominated by (LiPiv)2 and (LiPiv)4 molecules. The absolute values of the partial pressures of these molecules and their dependence on temperature were calculated. The standard enthalpies of sublimation of the main components of the saturated vapor were determined to be $${{\Delta }_{s}}H_{{298}}^{^\circ }$$ (LiPiv)2 = 174.2 ± 6.6 kJ/mol and $${{\Delta }_{s}}H_{{298}}^{^\circ }$$ (LiPiv)4 = 195.7 ± 4.5 kJ/mol. The enthalpies of dissociation of the dimeric molecules into the monomeric molecules and of the tetrameric molecules into the dimeric molecules were calculated by the second and third laws of thermodynamics; the average values of these enthalpies are $${{\Delta }_{D}}H_{{298}}^{^\circ }$$ (LiPiv)2 = 175.8 ± 13.5 kJ/mol and $${{\Delta }_{D}}H_{{298}}^{^\circ }$$ (LiPiv)4 = 155.2 ± 10.0 kJ/mol. The standard enthalpies of formation of LiPiv in the condensed and gas phase were estimated from the known thermodynamic characteristics of lithium acetate and radicals of acetic and pivalic acids: $${{\Delta }_{f}}H_{{298.15}}^{^\circ }$$ (LiPivsolid) ≤ –804 kJ/mol, $${{\Delta }_{f}}H_{{298.15}}^{^\circ }$$ (LiPivgas) ≤ –627 kJ/kmol, $${{\Delta }_{f}}H_{{298.15}}^{^\circ }$$ ((LiPiv)2(gas)) ≤ –1430 kJ/mol, and $${{\Delta }_{f}}H_{{298.15}}^{^\circ }$$ ((LiPiv)4(gas)) ≤ –3017 kJ/mol.

The paper presents critical analysis of experimental data, including the most recent published data on the gas-phase and heterogeneous equilibria of reactions involving higher chromium fluorides. The results of the analysis are presented as the enthalpies of formation (kJ/mol) of chromium fluorides in the condensed and gas phases: ΔfH°(CrF4, cr, 298.15 K) = –1202.5 ± 12.8; ΔfH°(CrF4, a, 298.15 K) = –1193.5 ± 13.1; ΔfH°(CrF4, g, 0) = –1098.9 ± 12.1; ΔfH°(CrF5, cr, 298.15 K) = –1243.8 ± 12.4; ΔfH°(CrF5, g, 0) = –1150.5 ± 12.1. The standard enthalpy of formation of chromium hexafluoride in the gas phase was determined to be ΔfH°(CrF6, g, 0) = –1077 kJ/mol. The possibility of existence of the mixed crystalline fluoride CrIVCrVF9 was demonstrated and its enthalpy and entropy of formation from crystalline CrF4 and CrF5 were estimated to be ∆rH°(298.15 K) = –12.6 kJ/mol, ∆rS°(298.15 K) = –1.5 J/(mol K). The recommended values provide explanation for the thermal behavior of higher chromium fluorides and the possibility of conducting some procedures with them in the processes that are qualitatively described in available literature.

An entry from the Cambridge Structural Database, the world’s repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.