This dilemma emerged in a tutorial this week where we were discussing the correct spelling of the word. Historically sulphur has been the typical form in British English, while sulfur is usual in American English, having emerged as a variant spelling among chemists in the 1920s. The word was borrowed into English from a French word sufere during the medieval period, which in turn was adopted from Latin, where the word was spelled both sulphur and sulfur. Usually English words spelled with <ph> are derived from Greek, where the <ph> represents the Greek letter ‘phi’, but in this case the ultimate source of the word is Arabic.
This might all seem pretty straightforward; the reason for the confusion in our class concerned the question of the correct spelling of the word in the international chemical industry. One student reported that a friend had told him that the only acceptable spelling of the word among chemists was now sulfur. To settle the debate, another class member texted her father, who conveniently happens to be a nuclear physicist, who reported that he continues to use the spelling sulphur. The International Union of Pure and Applied Chemistry did indeed officially adopt the sulfur spelling in 1990; in 1992 the Royal Society of Chemistry followed suit, issuing a press release adopting sulfur as the official international nomenclature for atomic element 16. But while this might seem to settle the case once and for all, it’s clear from our discussion that not all practising scientists have adopted the spelling change. This is a good example of the difficulties of reforming established spellings, even in a relatively defined group of users. One solution would be to drop the word completely, in favour of the much more evocative Germanic equivalent brimstone (literally ‘burning stone’).