Temperature dependence vapour pressure measurements of Mg(tmhd)2(tmeda) [(tmhd=2,2,6,6-tetramethyl-3,5-heptanedione, tmeda=N,N,N′,N′-tetramethylethylenediamine]

Vapor Pressure Measurements by Mass Loss Transpiration Method with a Thermogravimetric Apparatus

“…With T sample / T c ≈ 3 in both these qualifying experiments, the measured P values are actually three times lower than the known equilibrium values for the systems studied. Although the use of T sample in place of T c was seen in some more papers, , the need for correcting the results published earlier with T sample was advocated by Balakrishnan et al while reporting their results on solid TeO 2 . The total vapor pressure obtained in this work at T = 900 K (0.25 Pa) compared well with the partial pressure of TeO 2 (g) = 0.3 Pa obtained in our high-temperature mass spectrometric investigation, but the total pressure (the sum of the partial pressures of TeO 2 , TeO, Te 2 , and O 2 ) from the KEMS study is actually 0.59 Pa.…”

“…We show in Figure through some examples how the seemingly good transpiration P (apparent)-vs-d V /d t plots actually correspond to the mass loss data which might indicate that either the transpiration conditions were not perfect or that the actual vaporization equilibrium was different from the assumed one (in some or whole part of the experiment). In the top half of Figure , we have redrawn the plot of P (apparent) vs d V /d t (by reading off the data points from the plots) given in four references, ,,, and in the bottom half, we have given the corresponding plot of the apparent d m /d t vs d V /d t . The units for d m /d t (i.e., the y axis) in the bottom half are arbitrary because in the absence of actual d m /d t values in these references, we took them as [ P (apparent) × (d V /d t )].…”

“…Among the many more systems that have been subsequently studied by this group using the same technique, a few are cited here. [16][17][18] Commercial horizontal thermobalance systems were also sought to be employed afterward by others [19][20][21] for vapor pressure measurements by the transpiration method. A thermobalance appears to have some great advantages over a conventional transpiration system (with interrupted analysis), although the latter could offer more sensitivity in product analysis with such techniques as chemical analysis or radioactive assay (for radioactive elements): (1) mass-vs-time data can be easily acquired through computers at any desired intervals of time and at any programmed heating mode, gradient or isothermal; (2) mass-vs-time data at various flow rates can be obtained in a quick period of time; (3) both the above-mentioned possibilities without having to change the a Vapor pressures computed by using eq 2 and T c ) 298 K. b Mole fractions of (CsI) i (g) (i ) 1-3) computed from p(i) given in ref 12; Σp(i)) 16.0 Pa. c Mole fractions of (Te) i (g) (i ) 2-7) computed from p(i) given in ref 13; Σp(i) ) 11.9 Pa. d Congruent vaporization of TeO 2 (s) with vapor species TeO 2 (g), TeO(g), Te 2 (g), and O 2 (g).…”

Vapor Pressure Measurements of Sc(tmhd)3 and Synthesis of Stabilized Zirconia Thin Films by Hybrid CVD Technique Using Sc(tmhd)3, Zr(tmhd)4, and Al(acac)3 [tmhd, 2,2,6,6-tetramethyl-3,5-heptanedione; acac, 2,4-pentanedione] as Precursors

“…A horizontal TG/DTA analyzer (PerkinElmer, Pyris-Diamond) was used for recording TG. The location of both the sample and the reference pans of the balance in the uniform temperature zone of the horizontal tubular furnace facilitated elimination of errors leading to apparent weight changes caused by temperature gradients, buoyancy, thermal convection, convection currents within the furnace tube (made of alumina), thermomolecular drag, and electrostatic effects. − Careful calibration of TG with respect to apparent weight changes yielded reliable vapor pressure measurements. The arms of the thermobalance served as the temperature-cum-DTA sensors.…”

Tris(2,4‐pentanedionato)scandium(III) as a Precursor for Plasma‐Assisted Liquid Injection CVD to Deposit Nanocrystalline Scandia Thin Films

“…The experimental conditions were the same as described earlier. [31][32][33] There are several methods to measure a low vapor pressure, such as gas saturation (transpiration), Knudsen effusion, and vapor pressure balance. The conventional transpiration method is still the one that is widely used for determining low vapor pressures.…”