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1.
L. P. Ogorodova I. A. Kiseleva L. V. Mel’chakova M. F. Vigasina E. M. Spiridonov 《Russian Journal of Physical Chemistry A, Focus on Chemistry》2011,85(9):1492-1494
A calorimetric study of the natural pyrophyllite was performed by high-temperature melt calorimetry on a Tian-Calvet calorimeter.
Based on experimentally determined in this work for pyrophyllite and gibbsite, as well as previously obtained for corundum
and quartz, the total value of the enthalpy increment for the sample heated from room temperature to 973 K and the enthalpy
of dissolution at 973 K by Hess’s law, the enthalpy of formation of pyrophyllite of Al2[(OH)2/Si4O10] composed of elements was calculated at 298.15 K: Δf
H
elo(298.15 K) = −5639.8 ± 5.7 kJ/mol. 相似文献
2.
V. N. Emel’yanenko S. P. Verevkin C. Schick E. N. Stepurko G. N. Roganov M. K. Georgieva 《Russian Journal of Physical Chemistry A, Focus on Chemistry》2010,84(9):1491-1497
The enthalpies of combustion and formation of S-lactic acid at 298.15 K, Δc
H
mo(cr.) = −1337.9 ± 0.8 and Δf
H
mo(cr.) = −700.1 ± 0.9 kJ/mol, were determined by calorimetry. The temperature dependence of acid vapor pressure was studied
by the transpiration method, and the enthalpy of its vaporization was obtained, Δvap
H
o(298.15 K) = 69.1 ± 1.0 kJ/mol. The temperature and enthalpy of fusion, T
m (330.4 K) and Δm
H
o(298.15 K) = 14.7 ± 0.2 kJ/mol, were determined by differential scanning calorimetry. The enthalpy of formation of the acid
in the gas phase was obtained. Ab initio methods were used to perform a conformational analysis of the acid, calculate fundamental
vibration frequencies, moments of inertia, and total and relative energies of the stablest conformers. Thermodynamic properties
were calculated in the ideal gas state over the temperature range 0–1500 K. A thermodynamic analysis of mutual transformation
processes (the formation of SS- and RS(meso)-lactides from S-lactic acid and the racemization of these lactides) and the formation
of poly-(RS)-lactide from S-lactic acid and SS- and RS(meso)-lactides was performed. 相似文献
3.
L. P. Ogorodova I. A. Kiseleva 《Russian Journal of Physical Chemistry A, Focus on Chemistry》2011,85(10):1857-1859
The standard dehydroxylation enthalpy of natural talc Mg3[Si4O10](OH)2 (87.8 ± 9.0 kJ/mol at 298.15 K) and the enthalpy of formation of dehydrated talc from the elements (Δf
H
elo (298.15 K) = −5527.0 ± 9.0 kJ/mol) were determined for the first time using Hess’s law, based on the total values of the
enthalpy increments in heating a sample from room temperature to 973 K and the enthalpies of dissolution at 973 K for dehydrated
talc measured in this work and those previously determined for talc and corresponding oxides. 相似文献
4.
L. P. Ogorodova I. A. Kiseleva 《Russian Journal of Physical Chemistry A, Focus on Chemistry》2011,85(9):1489-1491
A thermochemical study of natural talc was performed by high-temperature melt dissolution calorimetry on a Tian-Calvet calorimeter.
Based on the total values of the increment in enthalpy upon heating the sample from room temperature to 973 K, and of the
dissolution enthalpy at 973 K measured in this work for talc and gibbsite (along with those determined for tremolite, brucite,
and their corresponding oxides), the enthalpy of formation was calculated for talc composed of elements, Mg3[Si4O10](OH)2, at 298.15 K: Δf
H
elo(298.15 K) = −5900.6 ± 4.7 kJ/mol. 相似文献
5.
M. R. Bisengalieva L. V. Mel’chakova L. P. Ogorodova M. F. Vigasina 《Russian Journal of Physical Chemistry A, Focus on Chemistry》2010,84(9):1481-1484
A thermal and thermochemical study of natural aqueous hydroxyl-containing diorthosilicate, hemimorphite Zn4[Si2O7](OH)2 · H2O, was performed. The step character of its thermal decomposition was studied using FTIR spectroscopy. Melt solution calorimetry
was used to determine the enthalpies of formation from oxides Δf
H
OOX (298.15 K) = −69.3 ± 9.9 kJ/mol and elements {ie1481-2} (298.15 K) = −3864.3 ± 10.2 kJ/mol. 相似文献
6.
N. N. Smirnova T. A. Bykova N. A. Polotnyanko N. D. Shikina I. L. Khodakovskii 《Russian Journal of Physical Chemistry A, Focus on Chemistry》2010,84(11):1851-1855
The temperature dependence of the heat capacity C
p
o = f(T) of palladium oxide PdO(cr.) was studied for the first time in an adiabatic vacuum calorimeter in the range of 6.48–328.86
K. Standard thermodynamic functions C
p
o(T), H
o(T) — H
o(0), S
o(T), and G
o(T) — H
o(0) in the range of T → 0 to 330 K (key quantities in different thermodynamic calculations with the participation of palladium compounds) were
calculated on the basis of the experimental data. Based on an analysis of studies on determining the thermodynamic properties
of PdO(cr.), the following values of absolute entropy, standard enthalpy, and Gibbs function of the formation of palladium
oxide are recommended: S
o(298.15) = 39.58 ± 0.15 J/(K mol), Δf
H
o(298.15) = −112.69 ± 0.32 kJ/mol, Δf
G
o(298.15) = −82.68 ± 0.35 kJ/mol. The stability of Pd(OH)2 (amorph.) with respect to PdO(cr.) was estimated. 相似文献
7.
S. N. Solov’ev A. A. Korunov K. G. Zubkov A. A. Firer 《Russian Journal of Physical Chemistry A, Focus on Chemistry》2012,86(3):516-518
The change in enthalpy in reactions of NiF3(s) with water and aqueous solution of potassium hydroxide are measured in the isothermal calorimetry mode at 298.15 K. The
standard enthalpy of formation Δf
H° of nickel trifluoride was found to be −816 ± 6 kJ/mol. 相似文献
8.
The relative enthalpies, ΔHo (0) and ΔHo (298.15), of stationary points (four minimum and three transition structures) on the •O3H potential energy surface were calculated with the aid of the G3MP2B3 as well as the CCSD(T)–CBS (W1U) procedures from which
we earlier found mean absolute deviations (MAD) of 3.9 kJ mol−1 and 2.3 kJ mol−1, respectively, between experimental and calculated standard enthalpies of the formation of a set of 32 free radicals. For
CCSD(T)-CBS (W1U) the well depth from O3 + H• to trans-•O3H, ΔHowell(298.15) = −339.1 kJ mol−1, as well as the reaction enthalpy of the overall reaction O3 + H•→O2 + •OH, ΔrHo(298.15) = −333.7 kJ mol−1, and the barrier of bond dissociation of trans-•O3H → O2 + •OH, ΔHo(298.15) = 22.3 kJ mol−1, affirm the stable short-lived intermediate •O3H. In addition, for radicals cis-•O3H and trans-•O3H, the thermodynamic functions heat capacity Cop(T), entropy So (T), and thermal energy content Ho(T) − Ho(0) are tabulated in the range of 100 − 3000 K. The much debated calculated standard enthalpy of the formation of the trans-•O3H resulted to be ΔfHo(298.15) = 31.1 kJ mol −1 and 32.9 kJ mol −1, at the G3MP2B3 and CCSD(T)-CBS (W1U) levels of theory, respectively. In addition, MR-ACPF-CBS calculations were applied
to consider possible multiconfiguration effects and yield ΔfHo(298.15) = 21.2 kJ mol −1. The discrepancy between calculated values and the experimental value of −4.2 ± 21 kJ mol−1 is still unresolved.
Note added in proof: Yu-Ran Luo and J. Alistair Kerr, based on the discussion in reference 12, recently presented an experimental
value of ΔfHo(298.15) = 29.7 ± 8.4 kJ mol−1 in the 85th edition of the CRC Handbook of Chemistry and Physics (in progress). 相似文献
9.
B. A. Knyazev V. F. Vakher 《Russian Journal of Physical Chemistry A, Focus on Chemistry》2011,85(5):804-810
The heats of the reaction of sodium with ethyl and methyl alcohol were determined by calorimetry. The difference in the standard
heats of the formation of triethylarsenite and arsenic trichloride was obtained by calorimetration of the reaction of arsenic
trichloride with sodium ethylate, the value of which was −382.42 ± 3.60 kJ/mol. The standard enthalpies of formation were
determined from a critical analysis of all data on thermochemistry of trialkylarsenites for the following compounds: triethylarsenite
Δf
H
298ℴ [(C2H5O)3As(liquid)] = (−704.38 ± 3.85) kJ/mol; trimethylarsenite Δf
H
298ℴ [(CH3O)3As(liquid)] = (−599.36 ± 1.88) kJ/mol. The values of standard enthalpies of formation were not adjusted for the following
substances in liquid state: arsenic trichloride (−321.96 ± 3.85 kJ/mol), tris-(diethylamido)arsenic(III) As(NEt2)3(liquid) (−129.81 ± 4.41 kJ/mol), tri-n-propylarsenite (−720.61 ± 4.49 kJ/mol), triisopropylarsenite (−756.11 ± 4.65 kJ/mol), tri-n-butylarsenite (−775.11 ± 4.53 kJ/mol), and triisobutylarsenite (−809.71 ± 4.59 kJ/mol). The use of sodium alcoxide solutions
for the calorimetration of halogen anhydrides of various acids was demonstrated. 相似文献
10.
I. Zięborak-Tomaszkiewicz 《Journal of Thermal Analysis and Calorimetry》2006,83(3):611-615
The energies of combustion
in fluorine of gallium nitride and indium nitride in wurzite crystalline structure
have been measured in a two-compartment calorimetric bomb, and new standard
molar enthalpies of formation have been calculated: ΔfHm0(GaN(cr)
298.15 K)= –(163.7±4.2) kJ mol–1
and ΔfHm0(InN(cr) 298.15 K)= –(146.5±4.6) kJ mol–1
. Comparison with the recommended values of the ΔfHm0 nitrides
from the literature is also presented. 相似文献
11.
S. N. Solov’ev A. A. Korunov K. G. Zubkov S. V. Kozhevnikova 《Russian Journal of Physical Chemistry A, Focus on Chemistry》2012,86(2):317-319
The enthalpies of the interaction of Ba[AuF6]2(cr.) with water and an aqueous potassium hydroxide solution have been measured in a calorimeter with an isothermal shell
at 298.15 K. The standard enthalpy of the formation of the studied compound Δf
H° Ba[AuF6]2(cr.) = −2341 ± 10 kJ/mol has been found by two independent methods based on these results and literature data. 相似文献
12.
M. F. Butman L. S. Kudin V. B. Motalov D. A. Ivanov V. V. Sliznev K. W. Krämer 《Russian Journal of Physical Chemistry A, Focus on Chemistry》2008,82(5):767-772
The thermodynamic stability of the LaBr 4 ? anion was for the first time studied by high-temperature mass spectrometry and nonempirical quantum-chemical methods. The experimental and theoretical enthalpies of the reaction $ LaBr_4^ - = Br^ - + LaBr_3 The thermodynamic stability of the LaBr4− anion was for the first time studied by high-temperature mass spectrometry and nonempirical quantum-chemical methods. The
experimental and theoretical enthalpies of the reaction were Δr
H°(298.15 K) = 302 ± 14 and 303 kJ/mol, respectively. The value Δf
H° (LaBr4−, g, 298.15 K) = −1105 ± 14 kJ/mol was recommended as the enthalpy of formation of the LaBr4− anion.
Original Russian Text ? M.F. Butman, L.S. Kudin, V.B. Motalov, D.A. Ivanov, V.V. Sliznev, K.W. Kr?mer, 2008, published in
Zhurnal Fizicheskoi Khimii, 2008, Vol. 82, No. 5, pp. 885–890. 相似文献
13.
The novel ternary solid complex Gd(C5H8NS2)3(C12H8N2) has been obtained from the reaction of hydrous gadolinium chloride, ammonium pyrrolidinedithiocarbamate (APDC), and 1,10-phenanthroline
(o-phen · H2O) in absolute ethanol. The complex was described by an elemental analysis, TG-DTG, and an IR spectrum. The enthalpy change
of the complex formation reaction from a solution of the reagents, Δr
H
m
ϑ
(sol), and the molar heat capacity of the complex, c
m
, were determined as being − 15.174 ± 0.053 kJ/mol and 72.377 ± 0.636 J/(mol K) at 298.15 K by using an RD496-III heat conduction
microcalorimeter. The enthalpy change of a complex formation from the reaction of the reagents in a solid phase, Δr
H
m
ϑ
(s), was calculated as being 52.703 ± 0.304 kJ/mol on the basis of an appropriate thermochemical cycle and other auxiliary
thermodynamic data. The thermodynamics of the formation reaction of the complex was investigated by the reaction in solution.
Fundamental parameters, the activation enthalpy (ΔH
≠
ϑ
), the activation entropy (ΔS
≠
ϑ
), the activation free energy (ΔG
≠
ϑ
), the apparent reaction rate constant (k), the apparent activation energy (E), the preexponential constant (A), and the reaction order (n), were obtained by the combination of the thermochemical data of the reaction and kinetic equations, with the data of thermokinetic
experiments. The constant-volume combustion energy of the complex, Δc
U, was determined as being −17588.79 ± 8.62 kJ/mol by an RBC-II type rotatingbomb calorimeter at 298.15 K. Its standard enthalpy
of combustion, Δc
H
m
ϑ
, and standard enthalpy of formation, Δf
H
m
ϑ
, were calculated to be −17604.28 ± 8.62 and −282.43 ± 9.58 kJ/mol, respectively.
The text was submitted by the authors in English. 相似文献
14.
S. N. Solov’ev K. I. Shatalov A. Ya. Dupal 《Russian Journal of Physical Chemistry A, Focus on Chemistry》2011,85(10):1855-1856
The enthalpies of reaction between crystalline (ClOF2)2[NiF6] and water and an aqueous solution of alkali are measured at 298.15 K using a highly sensitive isothermal shell calorimeter.
On the basis of these values and the published data, the standard enthalpy of formation of the studied compound is found by
two independent methods; its value is Δ
f
Ho(ClOF2)2[NiF6]](cryst.) = −1158 ± 11 kJ/mol. 相似文献
15.
M. R. Bissengaliyeva L. P. Ogorodova M. F. Vigasina L. V. Mel’chakova 《Russian Journal of Physical Chemistry A, Focus on Chemistry》2013,87(2):163-165
A thermochemical study of wulfenite, i.e., natural lead molybdate PbMoO4 (Kyzyl-Espe field deposit, Central Kazakhstan), is performed on a Setaram high-temperature heat-flux Tian-Calvet microcalorimeter (France). Enthalpies of the formation of wulfenite from oxides Δf H ox o (298.15 K) = ?88.5 ± 4.3 kJ/mol and simple substances Δf H°(298.15 K) = ?1051.2 ± 4.3 kJ/mol were determined by means of melt calorimetry. The Δf G°(298.15 K) of wulfenite corresponding to ?949.1 ± 4.3 kJ/mol was calculated using data obtained earlier for S°(298.15 K) = 161.5 ± 0.27 J/(K mol). 相似文献
16.
S. N. Solov’ev A. A. Korunov K. G. Zubkov K. A. Minasyan 《Russian Journal of Physical Chemistry A, Focus on Chemistry》2012,86(2):320-322
Enthalpies of the interaction of Ba[AuF6]2 · 4KrF2(cr.) with water and an aqueous potassium hydroxide solution are measured at 298.15 K in a calorimeter with an isothermal
shell. On the basis of these results and the literature data, the standard enthalpy of the formation of the studied compound
Δf
H° Ba[AuF6]2 · 4KrF2(cr.) = −3036 ± 21 kJ/mol are found using two independent methods. 相似文献
17.
Gavritchev K. S. Sharpataya G. A. Smagin A. A. Malyi E. N. Matyukha V. A. 《Journal of Thermal Analysis and Calorimetry》2003,73(1):71-83
Enthalpy of formation of lithium hexafluorophosphate was calculated based on the differential scanning calorimetry study of
heat capacity and thermal decomposition. It was found that thermal decomposition of LiPF6 proceeds at normal pressure in the temperature range 450-550 K. Enthalpy of LiPF6 decomposition is Δd
H(LiPF6, c, 298.15 K)= 84.27±1.34 kJ mole-1. Enthalpy of formation of lithium hexafluorophosphate from elements in standard state is Δf
H
0(LiPF6,c, 298.15 K) = -2296±3 kJ mol-1.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
18.
M. R. Bissengaliyeva D. B. Gogol’ N. S. Bekturganov 《Russian Journal of Physical Chemistry A, Focus on Chemistry》2011,85(2):157-163
The heat capacity of natural mineral, pyromorphite Pb5(PO4)3Cl, was measured over the temperature range 4.2–320 K using low-temperature adiabatic calorimetry. An anomalous temperature
dependence of heat capacity with a maximum at 273.24 K was observed between 250 and 290 K. The heat capacity, entropy, enthalpy,
and reduced thermodynamic potential of pyromorphite were calculated and tabulated over the temperature range 5–320 K. The
standard thermodynamic functions of the mineral are C
p298.15o = 414.98 ± 0.44 J/(mol K), S
298.15o = 585.31 ± 0.99 J/(mol K), H
298.15o − H
0o = 80.90 ± 0.08 kJ/mol, and Φ298.15o = 313.97 ± 0.84 J/(mol K). 相似文献
19.
J. Leitner K. Růžička D. Sedmidubský P. Svoboda 《Journal of Thermal Analysis and Calorimetry》2009,95(2):397-402
Heat capacity and enthalpy increments of calcium niobates CaNb2O6 and Ca2Nb2O7 were measured by the relaxation time method (2–300 K), DSC (260–360 K) and drop calorimetry (669–1421 K). Temperature dependencies
of the molar heat capacity in the form C
pm=200.4+0.03432T−3.450·106/T
2 J K−1 mol−1 for CaNb2O6 and C
pm=257.2+0.03621T−4.435·106/T
2 J K−1 mol−1 for Ca2Nb2O7 were derived by the least-squares method from the experimental data. The molar entropies at 298.15 K, S
m0(CaNb2O6, 298.15 K)=167.3±0.9 J K−1 mol−1 and S
m0(Ca2Nb2O7, 298.15 K)=212.4±1.2 J K−1 mol−1, were evaluated from the low temperature heat capacity measurements. Standard enthalpies of formation at 298.15 K were derived
using published values of Gibbs energy of formation and presented heat capacity and entropy data: Δf
H
0(CaNb2O6, 298.15 K)= −2664.52 kJ molt-1 and Δf
H
0(Ca2Nb2O7, 298.15 K)= −3346.91 kJ mol−1. 相似文献
20.
S. N. Solov’ev A. A. Firer K. A. Minasyan 《Russian Journal of Physical Chemistry A, Focus on Chemistry》2009,83(7):1239-1240
The enthalpies of interaction of XeF5[BF4](cr) (XeF6 · BF3) with water and an aqueous solution of alkali were measured on an isothermic-shell calorimeter at 298.15 K. The results of
measurements and literature data were used to calculate the standard enthalpy of formation of XeF5[BF4](cr) at 298.15 K, Δf
H
∘ = −1547 ± 10 kJ/mol.
Original Russian Text ? S.N. Solov’ev, A.A. Firer, K.A. Minasyan, 2009, published in Zhurnal Fizicheskoi Khimii, 2009, Vol.
83, No. 7, pp. 1394–1395. 相似文献