Combustion Calorimetry of Organometallic Compounds

Dissociation Dynamics and Thermochemistry of Tin Species, (CH3)4Sn and (CH3)6Sn2, by Threshold Photoelectron−Photoion Coincidence Spectroscopy

“…The two starting compounds, tetramethyltin and hexamethylditin, have experimentally determined heats of formation. All values for SnMe 4 listed in recent compilations, such as the NIST Website, 15 Rabinovich et al, 4 Martinho Simoes et al, 3 Cox and Pilcher, 16 and Pilcher, 17 refer back to the1963 heat of combustion work of Davies et al, 18 who reported a liquid-phase heat of formation of -52.3 ( 1.9 kJ • mol -1 . However, when this is corrected for a more recent SnO 2 (s) heat of formation 19 (which was available but not used in previous reviews), the value increases to -49.2 ( 1.9 kJ • mol -1 .…”

Heats of formation of GeH4, GeF4 and Ge(CH3)4

“…However, bomb calorimetry for germanium compounds is made difficult by the GeO 2 crystal product which can have both hexagonal and tetragonal forms whose heats of formation differ by 25 kJ/mol [24]. Pilcher [24] noted in his review of combustion calorimetry on organometallic compounds that this ''uncertainty concerning the form of the GeO 2 casts some doubt on static bomb combustion results'' of Germanium compounds. It is evident that there is no consensus in the literature for the heat of formation of Ge(CH 3 ) 4 .…”

“…Two gas-phase Ge(CH 3 ) 4 experimental heats of formation obtained by static bomb calorimetry are À102.6 ± 8.3 kJ/mol [22], and À69.8 kJ/mol [23]. However, bomb calorimetry for germanium compounds is made difficult by the GeO 2 crystal product which can have both hexagonal and tetragonal forms whose heats of formation differ by 25 kJ/mol [24]. Pilcher [24] noted in his review of combustion calorimetry on organometallic compounds that this ''uncertainty concerning the form of the GeO 2 casts some doubt on static bomb combustion results'' of Germanium compounds.…”

Size Effects on Cation Heats of Formation. III. Methyl and Ethyl Substitutions in Group IV XH4, X = C, Si, Ge, Sn, Pb

“…23,24 In general, although mentioning bomb calorimetry results, in determining heats of formation of the molecular ions we will disregard those obtained by static bomb techniques when there is other conflicting evidence. We note that a comparison of the results of static and rotating bomb calorimetry on organometallic compounds made by Pilcher 25 concluded that the static bomb results on silanes, germanes, and plumbanes are doubtful because of difficulties of incomplete combustion and/or in identifying or accounting for solid residue combustion products, whereas more credit can be given to static bomb measurements in the case of stannanes.…”

“…This table contains cation heats of formation of three derivatives which we derived by application of the Holmes–Lossing size-dependent linear relation. The results of static bomb calorimetry of stannanes appear to be valid, according to the assessment of Pilcher …”