Thermochemistry of the Si–O–N–C System with Relation to the Formation of Silicon Nitride

Thermodynamics of silicon nitride. I. Standard molar enthalpies of formation ΔfHmoat the temperature 298.15 K of α-Si3N4and β-Si3N4

“…One can ignore the second result because it is so uncertain, or can take a weighted mean of both; in either case, trs H o m = −(1 ± 4) kJ·mol −1 . It is probable that the enthalpy difference between the two forms of Si 3 N 4 is quite small at T = 298.15 K and p = 0.1 MPa, in agreement with the conclusions of Durham et al (47) We are grateful to Professor Suga (Kinki University, Osaka, Japan) who arranged for the provision of samples of Si 3 N 4 for exploratory work.…”

“…Smith and White (46) suggested that trs H o m "will be of the order of a few kcal"; Harrison and Harrison (17) mentioned the value 30 kJ·mol −1 , without attribution; and Durham et al (47) N 4 ), in particular the correction required by the relatively large amount of impurity, while the uncertainty in the second is dominated by uncertainties in the composition of the SRM mixtures. One can ignore the second result because it is so uncertain, or can take a weighted mean of both; in either case, trs H o m = −(1 ± 4) kJ·mol −1 .…”