An electron emissive material includes a composition including a metal oxide, where the metal oxide is at least one oxide of La, Ce, Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu, Y, Sc, Hf, or Zr, or any combinations thereof, where the metal oxide is present in a quantity that ranges from about 20% to 100% by weight of the total composition, where the composition is operable to emit electrons in a discharge medium in response to a thermal excitation, wherein the discharge medium under steady state operating conditions producing a total vapor pressure of less than about 2.times.10.sup.5 Pa. A lamp including an envelope, an electrode including an electron emissive material and a discharge medium, is also disclosed.