Explanatory notes
… - Boron; tellurium - Silicon : 2804.61 - - Containing by weight not less than 99.99 % of silicon … is obtained by electrolysing water, or from water‑gas, coke‑oven gas or hydrocarbons. It is generally regarded as a … their electrical properties ‑ particularly that of emitting coloured rays (used, for example, in neon signs) under the …