The high pressure P V T properties of deuterium oxide

Abstract

The high pressure isothermal compressibilities of deuterium oxide from 5 to 100 °C and 0 to 1000 bars applied or gauge pressure were determined from sound speed data. These compressibilities were used to derive an equation of state of the form V⁰P/(V⁰ − V^P) = B + A₁P + A₂P², where V⁰ and V^P are the specific volumes at an applied pressure of zero and P; and B, A₁, and A₂ are polynomial functions of temperature. The compressibilities derived from this equation of state are consistent with those derived from the sound speed data to ±0.016×10⁻⁶ bar⁻¹ over the entire pressure and temperature range (this is equivalent to ∼0.2 m sec⁻¹ in sound speed). The 1 atm sound‐derived compressibilities agree on the average to ±0.06×10⁻⁶ bar⁻¹ with the direct measurements of Millero and Lepple. The P–V–T data from the sound‐derived equation are compared with the high pressure work of Bridgman, Kesselman, Juza et al., and Emmet and Millero. Good agreement (average deviation of ±28×10⁻⁶ cm³ g⁻¹) was found with the recent specific volume measurements of Emmet and Millero. The P–V–T properties of D₂O are compared to pure water. D₂O and H₂O are shown to follow similar trends. Contrary to previous reports, the D₂O/H₂O ratios of the specific volumes and specific heats are shown to be functions of both temperature and pressure.