Mass spectroscopic investigation of the equilibrium dissociation of gaseous Sb2, Sb3, Sb4, SbP, SbP3, and P2

Abstract

Knudsen effusion mass spectroscopic studies of the vapor above a gadolinium antimonide-molybdenum phosphide-graphite system led to the determination of the standard enthalpy changes, Δ H298°(kcal), for the following reactions: Sb4(g)=2Sb2(g) (71.3 ± 1.8), Sb4(g) =4Sb(g) (215.0 ± 3.0), Sb2(g) = 2Sb(g) (71.8 ± 1.0), Sb3(g)=3Sb(g)(129 ± 4), P2(g) =2P(g) (117.1 ± 1.1), Sb2(g) + P2(g) = 2SbP(g) (17.6 ± 0.4), SbP(g) = Sb(g)+P(g) (86.0 ± 1.2), and 2SbP3(g)=Sb2(g)+3P2(g) (149 ± 8). These reaction enthalpies have been combined with appropriate literature data to obtain the dissociation or atomization energies D°298 and standard heats of formation Δ H°f,298 of the molecules given. D298°kcal mol−1or kJ mol−1Δ Hf,298°kcal mol−1or kJ mol−1Sb271.8 ± 1.0300.4 ± 4.854.7 ± 2.2288.7 ± 9.2Sb3129.0 ± 4.0539.7 ± 16.760.7 ± 5.8254.0 ± 24.3Sb4215.0 ± 3.0899.6 ± 12.637.9 ± 5.4158.6 ± 22.6SbP85.7 ± 0.9358.6 ± 3.857.3 ± 1.6239.8 ± 6.7SbP3285.8 ± 5.21195.8 ± 21.816.8 ± 6.070.3 ± 25.1

Thermodynamic investigation of the lead molecules Pb2, Pb3, and Pb4 by mass spectrometry

“…Similar fragmentation behavior has been found for Sn, Sb, and Bi species. [20][21][22] The pressure calibration constant, k208Pb ==0.056 6 was obtained by the relation P~b == k20BPb 1 208Pb T, where P~b is the literature vapor pressure of lead 37 and T the absolute temperature. The k j values for the lead molecules i were calculated according to k nj == k20BPb UpbYPbn20BPb Ej/(ujYj nl E pb ) • The electron impact cross section of atomic lead, u pb , was taken from Mann.…”

Density functional study of structure and dynamics in liquid antimony and Sbn clusters

“…49 Laser induced fluorescence provides the most detailed information about Sb 2 , 50 Raman spectra of the dimer and tetramer have been measured in neon matrices, 51 and the equilibrium dissociation energies of Sb 2 , Sb 3 , and Sb 4 have been measured in the gas phase. 52 Calculations using correlated wave functions have been performed on Sb 2 , 53,54 Sb 3 , 55,56 and Sb 4 , 57 but DF methods have been favored for larger clusters. They include Sb − n (n = 2-9), 49 Sb n (n = 2-8, 12), 58 and Sb n (n = 2-10).…”

Cohesive energies of the elements

“…Sb-Values tabulated are based on a rev1s1on of Hultgren's tabulation by Professor Gerd Rosenblatt(l2) incorporating Hultgren's list of additional references plus later publications (23,48,49).…”