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30. The thermodynamic and physical properties of beryllium compounds. VI. The heat of formation of beryllium nitride
Classified abstracts 27--36 16 26. Surface diffusion of hydrogen on carbon. (USA) The slow uptake of hydrogen on platinized carbon is due to activated diffusion of adsorbed hydrogen atoms away from platinum centers which chemisorb molecular hydrogen rapidly. The phenomenon has been studied both with hydrogen and deuterium, between 300 and 392 °, from 30 to 60 cm of pressure on carbon samples containing 0.2 and 1 per cent platinum by weight. (Authors) A J Robell, E V Ballou and M Boudart, J Phys Chem, 68, Oct 1964,
2748-2753. 16 27. The nature of residual O H groups on a series of near-faujasite zeolites. (USA) The infrared spectra of a series of ion-exchanged zeolites of the faujasite family have been measured. The exchanged materials contained the ions: sodium, lithium, potassium, silver, cadmium, calcium, barium, and strontium. It is shown that these faujasites retain OH (and OD) groups on their surface, even after evacuation at 450°. These spectra are compared and contrasted with those of alumina, silica, and titania. It is considered that some of the OH groups are attached to "alumina-like" parts of the lattice, and some to the "silica-like" part of the lattice. Finally, a third type of OH groups is related to the presence of exchangeable cations. (Authors) J L Carter, P J Lucchesi and D J C Yates, J Phys Chem, 68,
June 1964, 1385-1391.
these it can be predicted that this phase will become unstable below 700 ° and disproportionate into MoP and a phosphide of lower phosphorus content. (Author) K A Gingerich, JPhys Cehm, 68, Sept 1964, 2514-2522. 17 32. A torsion effusion study of the reaction of graphite with oxides of thorium and zirconium. (USA) The torsion effusion method is found to give useful results for the study of the solid-solid reaction between ThO2 and graphite which produces ThC~ and CO. Near equilibrium pressures do not appear to be established for the reaction of graphite with ZrO,, however. Thermodynamic properties of ThC2 are discussed. (Authors) J R Hollahan and N W Gregory, J Phys Chem, 68, Aug 1964,
2346-2351. 17 33. Vaporization of thorium dicarbide. (USA) A mass spectrometric investigation was carried out on the vaporization processes and thermodynamics of vaporization of solid ThC2. The carbide was heated in a graphite Knudsen cell and the vapors were analyzed. The partial pressures of Th(g) and ThC2(g) in equilibrium with the carbon-saturated solid were found to be of comparable magnitude in the temperature range investigated, 23712642°K. The enthalpy of sublimation of ThC2(s) to ThC2(g) is 198.1-~ 3.5kcal/g.f.w, and to Th(g) is 168.4 ± 3.5kcal/g.f.w. The calculated AHf%98 of formation of ThC2 is --30.7 ~ 3.7 kcal/ g.f.w. (Authors) D D Jackson, G W Barton Jr, O H Krikorian and R S Newbury,
J Phys Chem, 68, June 1964, 1516-1523.
17. Thermodynamics 17 Free-molecule drag on evaporating or condensing spheres. See Abstr. No. 6. 17 Characteristic condensation temperature of thin films. See Abstr. No. 75. 17 : 32 28. British National Bubble Chamber at CERN. ( Great Britain)
Engineer, 218 (5661), 24 July, 1964, 148. 17:32 29. Large liquid hydrogen filled bubble chamber. (Great Britain)
Engineer, 218 (5667), 4 Sept 1964, 391-392. 17 30. The thermodynamic and physical properties of beryllium compounds. VI. The heat of formation of beryllium nitride. (USA) The decomposition pressures of solid Be3N2 to Be(g) and N2(g) over the temperature range 1450-1650°K have been determined by the torsion effusion technique. From the data obtained in this research and available thermodynamic properties of the species involved, a third-law value of AH~,298 for Be3N2(s) has been found to be 140.3 4- 1.5 kcal/mole. (Authors) R E Yates, M A Greenbaum and M Farber, J Phys Chem, 68,
Sept 1964, 2682-2686. 17 31. Tensimetric analysis of the MoP-MoPo.7 partial system with a mass spectrometer and phosphorus decomposition pressures and homogeneity range of molybdenum monophosphide. (USA) The vaporization of molybdenum monophosphidc, MoP, has been studied by the Knudsen effusion technique in combination with a mass spectrometer. The major vapor species was P2 with a small amount of P4. No gaseous molybdenum monophosphide species were observed. At 1250 ° molybdenum monophosphide vaporizes by decomposition into gaseous phosphorus and a phosphide with complex crystal structure and approximate composition of MoP0.~. The width of the homogeneity range, n, in MoPI-n was found to be less than 10 3. An average molal enthalpy of decomposition, AH13~ooK, of 107.84 ~ 0.42 kcal/mole of P~(g) was obtained from a second-law treatment for the composition range MoP0.90MOP0.80, where the uncertainty represents the standard deviation. The temperature dependence of the P~ decomposition pressure was found to be linear over the temperature range 1195-1525°K and can be expressed by the equation log p (atm) [P~] = --23566/T 411.6594 + 0.0335. Preliminary data for the molal enthalpy of P~ decomposition and the temperature dependence of the P2 decomposition pressures have been obtained for the MOP0.7 phase. F r o m
17 34. The vapor pressure of liquid thallous chloride and the partial pressures of monomer and dimer. (USA) The vapor pressure of liquid thallous chloride was measured by a quasi-static method from the melting point to the boiling point. The results can be represented by the equation: log p : --6923/T -!- 19.850 --3.5 log T. The vapor pressure was also measured by a transpiration method. The partial pressures of monomer and dimer in the gas were calculated from these measurements. The dimer was the minor species and constituted about 5 per cent of the vapor near the melting point and about 15 per cent near the boiling point. The heats of evaporation at 1000°K were 24.4 kcal to monomer and 31.8 kcal to dimer. The corresponding entropies were 22.0 and 25.7 e.u. The thermodynamic functions for the gaseous dissociation of the dimer were compared with those for alkali chlorides. (Author) D Cubicciotti, JPhys Chem, 68, June 1964, 1528-1532. 17 35. Manganese vapor pressures in equilibrium with manganese-ironnickel solid solutions. (USA) The partial pressure of manganese gas in equilibrium with manganese-iron-nickel solid solutions was measured as a function of concentration at 1232°K by the Knudsen effusion technique coupled with a vacuum microbalance. The manganese-nickel system exhibits negative departures from an ideal solution with the exception of the /3-phase alloys where the nonideality is slightly positive. These departures decrease as iron replaces nickel in solid solution. The Gibbs excess molal free energy was calculated for ternary concentrations from the ternary G i b b s - D u h e m equation and estimated for the iron-nickel binary concentrations. Nonregular solution behaviour exists in both binary and ternary concentrations. (Authors) J H Smith, H W Paxton, C L MeCabe, J Phys Chem, 68, June
1964, 1345-1354. 17 36. Evaporation and condensation of spherical bodies in noneontinuum regimes. (USA) The theory of the evaporation and condensation of spherical bodies is discussed for the slip-flow and free,molecule regimes. The value of the slip-flow density difference coefficient is discussed and the method of calculation in the slip-flow regime of evaporation and condensation rates of spherical bodies is outlined and illustrated with a simple example. Expressions for the evaporation and condensation rates in the free-molecule regime are given in detail for general dynamical states of the gas phase. (Author) J R Broek, JPhys Chem, 68, Oct 1964, 2857-2862. 43
2748-2753. 16 27. The nature of residual O H groups on a series of near-faujasite zeolites. (USA) The infrared spectra of a series of ion-exchanged zeolites of the faujasite family have been measured. The exchanged materials contained the ions: sodium, lithium, potassium, silver, cadmium, calcium, barium, and strontium. It is shown that these faujasites retain OH (and OD) groups on their surface, even after evacuation at 450°. These spectra are compared and contrasted with those of alumina, silica, and titania. It is considered that some of the OH groups are attached to "alumina-like" parts of the lattice, and some to the "silica-like" part of the lattice. Finally, a third type of OH groups is related to the presence of exchangeable cations. (Authors) J L Carter, P J Lucchesi and D J C Yates, J Phys Chem, 68,
June 1964, 1385-1391.
these it can be predicted that this phase will become unstable below 700 ° and disproportionate into MoP and a phosphide of lower phosphorus content. (Author) K A Gingerich, JPhys Cehm, 68, Sept 1964, 2514-2522. 17 32. A torsion effusion study of the reaction of graphite with oxides of thorium and zirconium. (USA) The torsion effusion method is found to give useful results for the study of the solid-solid reaction between ThO2 and graphite which produces ThC~ and CO. Near equilibrium pressures do not appear to be established for the reaction of graphite with ZrO,, however. Thermodynamic properties of ThC2 are discussed. (Authors) J R Hollahan and N W Gregory, J Phys Chem, 68, Aug 1964,
2346-2351. 17 33. Vaporization of thorium dicarbide. (USA) A mass spectrometric investigation was carried out on the vaporization processes and thermodynamics of vaporization of solid ThC2. The carbide was heated in a graphite Knudsen cell and the vapors were analyzed. The partial pressures of Th(g) and ThC2(g) in equilibrium with the carbon-saturated solid were found to be of comparable magnitude in the temperature range investigated, 23712642°K. The enthalpy of sublimation of ThC2(s) to ThC2(g) is 198.1-~ 3.5kcal/g.f.w, and to Th(g) is 168.4 ± 3.5kcal/g.f.w. The calculated AHf%98 of formation of ThC2 is --30.7 ~ 3.7 kcal/ g.f.w. (Authors) D D Jackson, G W Barton Jr, O H Krikorian and R S Newbury,
J Phys Chem, 68, June 1964, 1516-1523.
17. Thermodynamics 17 Free-molecule drag on evaporating or condensing spheres. See Abstr. No. 6. 17 Characteristic condensation temperature of thin films. See Abstr. No. 75. 17 : 32 28. British National Bubble Chamber at CERN. ( Great Britain)
Engineer, 218 (5661), 24 July, 1964, 148. 17:32 29. Large liquid hydrogen filled bubble chamber. (Great Britain)
Engineer, 218 (5667), 4 Sept 1964, 391-392. 17 30. The thermodynamic and physical properties of beryllium compounds. VI. The heat of formation of beryllium nitride. (USA) The decomposition pressures of solid Be3N2 to Be(g) and N2(g) over the temperature range 1450-1650°K have been determined by the torsion effusion technique. From the data obtained in this research and available thermodynamic properties of the species involved, a third-law value of AH~,298 for Be3N2(s) has been found to be 140.3 4- 1.5 kcal/mole. (Authors) R E Yates, M A Greenbaum and M Farber, J Phys Chem, 68,
Sept 1964, 2682-2686. 17 31. Tensimetric analysis of the MoP-MoPo.7 partial system with a mass spectrometer and phosphorus decomposition pressures and homogeneity range of molybdenum monophosphide. (USA) The vaporization of molybdenum monophosphidc, MoP, has been studied by the Knudsen effusion technique in combination with a mass spectrometer. The major vapor species was P2 with a small amount of P4. No gaseous molybdenum monophosphide species were observed. At 1250 ° molybdenum monophosphide vaporizes by decomposition into gaseous phosphorus and a phosphide with complex crystal structure and approximate composition of MoP0.~. The width of the homogeneity range, n, in MoPI-n was found to be less than 10 3. An average molal enthalpy of decomposition, AH13~ooK, of 107.84 ~ 0.42 kcal/mole of P~(g) was obtained from a second-law treatment for the composition range MoP0.90MOP0.80, where the uncertainty represents the standard deviation. The temperature dependence of the P~ decomposition pressure was found to be linear over the temperature range 1195-1525°K and can be expressed by the equation log p (atm) [P~] = --23566/T 411.6594 + 0.0335. Preliminary data for the molal enthalpy of P~ decomposition and the temperature dependence of the P2 decomposition pressures have been obtained for the MOP0.7 phase. F r o m
17 34. The vapor pressure of liquid thallous chloride and the partial pressures of monomer and dimer. (USA) The vapor pressure of liquid thallous chloride was measured by a quasi-static method from the melting point to the boiling point. The results can be represented by the equation: log p : --6923/T -!- 19.850 --3.5 log T. The vapor pressure was also measured by a transpiration method. The partial pressures of monomer and dimer in the gas were calculated from these measurements. The dimer was the minor species and constituted about 5 per cent of the vapor near the melting point and about 15 per cent near the boiling point. The heats of evaporation at 1000°K were 24.4 kcal to monomer and 31.8 kcal to dimer. The corresponding entropies were 22.0 and 25.7 e.u. The thermodynamic functions for the gaseous dissociation of the dimer were compared with those for alkali chlorides. (Author) D Cubicciotti, JPhys Chem, 68, June 1964, 1528-1532. 17 35. Manganese vapor pressures in equilibrium with manganese-ironnickel solid solutions. (USA) The partial pressure of manganese gas in equilibrium with manganese-iron-nickel solid solutions was measured as a function of concentration at 1232°K by the Knudsen effusion technique coupled with a vacuum microbalance. The manganese-nickel system exhibits negative departures from an ideal solution with the exception of the /3-phase alloys where the nonideality is slightly positive. These departures decrease as iron replaces nickel in solid solution. The Gibbs excess molal free energy was calculated for ternary concentrations from the ternary G i b b s - D u h e m equation and estimated for the iron-nickel binary concentrations. Nonregular solution behaviour exists in both binary and ternary concentrations. (Authors) J H Smith, H W Paxton, C L MeCabe, J Phys Chem, 68, June
1964, 1345-1354. 17 36. Evaporation and condensation of spherical bodies in noneontinuum regimes. (USA) The theory of the evaporation and condensation of spherical bodies is discussed for the slip-flow and free,molecule regimes. The value of the slip-flow density difference coefficient is discussed and the method of calculation in the slip-flow regime of evaporation and condensation rates of spherical bodies is outlined and illustrated with a simple example. Expressions for the evaporation and condensation rates in the free-molecule regime are given in detail for general dynamical states of the gas phase. (Author) J R Broek, JPhys Chem, 68, Oct 1964, 2857-2862. 43