To obtain the metal chemically pure a specially prepared pure oxide or salt of zinc is distilled.
Chemically related to vanadium are the two elements tantalum and columbium or niobium.
Lord Rayleigh in 1894 found that the density of atmospheric nitrogen was about 2% higher than that of chemically prepared nitrogen, a discovery which led to the isolation of the rare gases of the atmosphere.
Chemically pure sodium nitrate can be obtained by repeated recrystallization of Chile saltpetre or by synthesis.
It is not at all certain that the masses on which coral reefs are built consist entirely of the remains of the skeletons of reef-forming organisms and it is probable that chemically precipitated carbonate of lime predominates.