Where a choice exists between British and American spelling, use the spelling preferred by IUPAC:
aluminium not aluminum
sulfur not sulphur
caesium not cesium
Watch out for different spellings for elements and their different valencies in compounds:
phosphorus [for elemental phosphorus]
phosphoric [for phosphorus compounds with a valency of 5; eg phosphoric acid, orthophosphonic acid]
phosphorous [for reduced phosphorus compounds with a valency of 3; eg phosphorous acid – also known as phosphonic acid; hypophosphorous acid]
sulfur [for elemental sulfur]
sulfurous [for sulfur compounds with a valency of 4; eg sulfurous acid]
sulfuric [for sulfur compounds with a valency of 6; eg sulfuric acid]
sulfonate, sulfate, sulfite … [and ALL other derivatives, including endosulfan and similar terms]
Note: IUPAC has standardised the spelling of sulfur (not sulphur). The only place that the ph spelling should be retained is in formal names (such as bird or insect names):
sulphur-crested cockatoo not sulfur-crested cockatoo
bordered sulphur not bordered sulfur
Did you know?
The last word on sulfur!
The spelling sulfur is often thought of as American and sulphur as British. However, this is incorrect, and sulfur is the standard spelling recommended by IUPAC, and used by chemists and other science disciplines worldwide. Australian authors outside science often mistakenly think that the choice of spelling is still optional and argue for sulphur because of the association with British spelling. But, in addition to the international standardisation of the spelling by IUPAC, sulfur is the sounder spelling, originating from Latin (not Greek). The word’s earliest spellings were sulfur and sulpur, and the introduction of ph into the spelling is a scholarly mistake.
(Adapted from Pam Peters’s Cambridge guide to Australian English usage)
