The heat of formation of tita nium tetraiodide was determin ed relative to tha t of t iLan iu l11 tetrabromide by comparison of t.heir heatf' of hydrolys is in dilute sulfuric ac id . The difference in t he heats of formation may be expressed by the equation:ilH(2 5° C) = -230.91 ± O.75 ki / mole (-55.19 ± 0. 18 kcal/ mole) .By taking th e heat of format ion of TiBr.(c) as -616.72 ± 4.60 ki / molc the h eat of fo r mal ion of TiI.(c) is calculated to be -385.8 1 ± 4.64 ki / mole ( -91.21 ± i.1l kcal/ mole) . The h eats of hyd rolys is of TiBr. a nd TiCI. were similarly meas ured ; the v,\lue obtained for the difference (186.77 ± 1. 34 kj j mole) is in good agreement with t he diffe re nce be tween the c:iirecLly determin ed heats of form a t ion (187.11 ± 5.35 kj /mo le).

in which t he uncertainty represents twicc the estimated overall stan dard deviation of the re s ult.

The heat of deco mposit ion of potassium perch lorate into potassium chl oride and oxygen has been determin ed in a bomb calorimeter. Th e process may be represented by t he eq uation:KCIO

Calorimetric m easure ments of t he heat s of solut ion of L iClO, (c), N H ,ClO,(e), a nd NaCIO, (c) have bee n ma de. The res ults have bee n combined wit h t he heats of format io n of K CIO,(c), K CI(c), Li CI(c), N H ,CI(c), a nd NaCI(c), t o obtain t he followin g heats of A brief s ummary of oth er recent da la has been in cluded .

The heat of formation of ber ylliu m chloride has been determined, by t he direct combin ation of t he eleme nt s in a calorimeter, accordin g to t il e process, Be(e) + C12(g) = B eC12(c), c.Ho (25°C) = -493.85 ± 2.35 kj / mole, = -118.03 ± 0.56 kcal/ mo le.The d ata obtained by other investigators a re disc ussed briefi y.