Energetics of Manganese Oxides

1995 ◽  
Vol 398 ◽  
Author(s):  
S. Fritsch ◽  
A. Navrotsky
Keyword(s):  
Phase Diagram ◽  
High Temperature ◽  
Enthalpy Of Formation ◽  
Manganese Oxides ◽  
Temperature Drop ◽  
Solution Calorimetry ◽  
Drop Calorimetry ◽  
Thermodynamic Cycles

ABSTRACTThe energetics of some manganese oxides : pyrolusite ΜnO2, bixbyite Μn2O3, hausmannite Μn3O4 and manganosite MnO were studied by transposed temperature drop calorimetry and high temperature drop solution calorimetry in molten 2PbOB2O3 at 977 K. The enthalpies of oxidation at 298 K in the Mn-O system, determined by appropriate thermodynamic cycles, are (in kJ/mol O2) : −441.4 ± 5.8 for the reaction 6 MnO + O2 -> 2 Mn3O4, −201.8 ± 8.7 for 4 Mn3O4 + O2 -> 6 Mn2O3 and −162.1 ± 7.2 for 2 Mn2O3 + O2 -> 4 ΜnO2 These values agree very well with previous data obtained by equilibrium ρθ2 measurements and indicate that direct calorimetrie measurements are well suited to obtain reliable enthalpy of formation data for oxides containing manganese in the 2+, 3+ and 4+ states. The phase diagram of the Mn-O system was calculated using these new values of enthalpies.

scholarly journals Enthalpy of formation of U3Si2: A high-temperature drop calorimetry study

2018 ◽  
Vol 507 ◽  
pp. 44-49 ◽  
Author(s):  
Xiaofeng Guo ◽  
Joshua T. White ◽  
Andrew T. Nelson ◽  
Artaches Migdisov ◽  
Robert Roback ◽  
...  
Keyword(s):  
High Temperature ◽  
Enthalpy Of Formation ◽  
Temperature Drop ◽  
Drop Calorimetry

Enthalpy of Formation of Rare-earth Silicates Y2SiO5 and Yb2SiO5 and N-containing Silicate Y10(SiO4)6N2

1999 ◽  
Vol 14 (4) ◽  
pp. 1181-1185 ◽  
Author(s):  
Jian-Jie Liang ◽  
Alexandra Navrotsky ◽  
Thomas Ludwig ◽  
Hans J. Seifert ◽  
Fritz Aldinger
Keyword(s):  
Rare Earth ◽  
High Temperature ◽  
Enthalpy Of Formation ◽  
Temperature Drop ◽  
Solution Calorimetry ◽  
Enthalpies Of Formation ◽  
Binary Oxides ◽  
Standard Enthalpies Of Formation ◽  
Oxygen Gas ◽  
The Enthalpy Of Formation

The enthalpies of formation of two rare-earth silicates (Y2SiO5 and Yb2SiO5) and a N-containing rare-earth silicate Y10(SiO4)6N2 have been determined using high-temperature drop solution calorimetry. Alkali borate (52 wt% LiBO2·48 wt% NaBO2) solvent was used at 800 °C, and oxygen gas was bubbled through the melt. The nitrogen-containing silicate was oxidized during dissolution. The standard enthalpies of formation are for Y2SiO5, Yb2SiO5, and Y10(SiO4)6N2, respectively, –22868.54 ± 5.34, –22774.75 ± 8.21, and –14145.20 ± 16.48 kJ/mol from elements, and –52.53 ± 4.83, –49.45 6 ± 8.35, and –94.53 ± 11.66 kJ/mol from oxides (Y2O3 or Yb2O3, SiO2) and nitride (Si3N4). The silicates and N-containing silicate are energetically stable with respect to binary oxides and Si3N4, but the N-containing silicate may be metastable with respect to assemblages containing Y2SiO5, Si3N4, and SiO2. A linear relationship was found between the enthalpy of formation of a series of M2SiO5 silicates from binary oxides and the ionic potential (z/r) of the metal cation.

Experimental results of the Li-Pb-Pt system obtained by the high temperature drop calorimetry

2021 ◽  
pp. 115824
Author(s):  
S. Terlicka ◽  
A. Dębski ◽  
W. Gąsior ◽  
A. Fornalczyk ◽  
M. Saternus
Keyword(s):  
High Temperature ◽  
Temperature Drop ◽  
Experimental Results ◽  
Drop Calorimetry

High temperature drop calorimetry measurements of enthalpy increment in Ti–xTa (x=5, 10, 15, 20 mass%) alloys

2014 ◽  
Vol 75 (2) ◽  
pp. 283-295 ◽  
Author(s):  
Madhusmita Behera ◽  
Subramanian Raju ◽  
Ganapathy Panneerselvam ◽  
Mythili Rangachari ◽  
Saroja Saibaba
Keyword(s):  
High Temperature ◽  
Temperature Drop ◽  
Enthalpy Increment ◽  
Drop Calorimetry
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