The temperature dependences of the vapor pressure of solid and liquid
nickel are determined by the integral version of the Knudsen effusion
method in the temperature range of 1273 - 1802 K. The respective regre
ssion equations are given. Sublimation enthalpy of nickel at 298.15 K,
determined with due regard for errors in the thermodynamic functions,
is 424.5 +/- 2.0 kJ/mol.