Heat Capacity of Potassium Borohydride (KBH) From 15 to 375 °K. Thermodynamic Properties From 0 to 700 °K.

The heat capacity of potassium borohydride (KBH) was determined from about 15 to 375 °K by means of an adiabatic calorimeter. A table of thermodynamic functions was calculated up to 700 °K using the data obtained along with those at high temperatures found in the literature. A solid-solid (order-disorder) transition was observed at 77.

Calorimetric Properties of Some Alkali Pentaborate Hydrates From 15 to 370 °K.

Measurements of the heat capacity of ammonium pentaborate tetrahydrate (NHBO·4HO), potassium pentaborate tetrahydrate (KBO·4HO), and sodium pentaborate pentahydrate (NaBO·5HO) were made in the range of about 15 to 370 °K and the data were used to obtain a table of smoothed values of thermodynamic functions from 0 to 370 °K. The measurements on sodium pentaborate pentahydrate were terminated at 345 °K because the temperature drifts that were observed above this temperature were considered to arise from gradual volatilization of the water of hydration.

Thermodynamic Properties of Some Methylphosphonyl Dihalides From 15 to 335 °K.

Measurements of the heat capacity of methylphosphonyl difluoride (CHPOF), methyl phosphonyl dichloride (CHPOCl), and methylphosphonyl chlorofluoride (CHPOClF) were made from about 15 to 335 °K by means of an adiabatic calorimeter. These highly reactive and toxic substances were purified in a completely closed glass apparatus by combining slow crystallization and fractional melting procedures. The purities determined by the freezing-curve method are shown to be generally in agreement with those values obtained by the calorimetric method.