“ Two oxides of the element are definitely known, viz., the dioxide, TeO2, and the trioxide, TeO3, whilst a monoxide, TeO, has also been described. The dioxide is formed by burning tellurium in air or by warming it with nitric acid. It is a colourless crystalline solid which readily fuses to a yellow liquid. The trioxide is an orange coloured solid which is formed when telluric acid is strongly heated. Tellurous acid, H2TeO3, is obtained when the tetrachloride is decomposed by water, or on dissolving tellurium in nitric acid and pouring the solution into water. ”

“ It burns, and also, like sulphuretted hydrogen, precipitates many metals from solutions of their salts. It may be liquefied, the liquid boiling at 0° C., and on further cooling, it solidifies, the solid melting at −48° C. Many tellurides of metals have been examined by C. A. Tibbals (Jour. Amer. Chem. Soc., 1909, 31, p. 902) who obtained the sodium and potassium tellurides by the direct union of their component elements and others from these by precipitation. ”

“ A. Gutbier (Ann., 1905, 342, p. 266) by reduction of the dioxide obtained 127.6; Marckwald, by determining the ratio of telluric acid to tellurium dioxide, obtained 126.85; H. B. Baker (Jour. Chem. Soc., 1907, 91, p. 1849) , by determining the ratio of tellurium dioxide to oxygen and by analysis of tellurium tetra bromide, obtained 127.60, and V. Lenher (Jour. Amer. Chem. Soc., 1909, 31, p. 20) , by heating the double salt, TeBr4⋅2KBr, first in chlorine and finally in a current of hydrochloric acid to convert it into potassium chloride, obtained the value 127.55. ”