The Group 3 question

I have almost completed the d-block and it’s come together nicely. The patterns take their inspiration from a wide time-span: from alchemy and classical mythology through to modern technology and applications. Many are pictorial; others are closer to the geometric patterns of traditional blackwork embroidery. As is befitting the transition elements, there are several references to colour – the rainbow of colours of iridium compounds, the yellow of chrome pigments and the rose-red of rhodium salts. Many outstanding scientists are honoured and a further two continents are referenced, with platinum from South America and Ernest Rutherford from New Zealand.

The eagle-eyed among you will notice that I have two elements missing – scandium and yttrium – but the question is where to put them? For some time chemists have debated whether Group 3 should consist of scandium, yttrium, lanthanum and actinium, or scandium, yttrium, lutetium and lawrencium. Many periodic tables get round the issue by having an f-block that is 15 elements wide and includes La, Ac, Lu and Lr, but as I am making a 32-column table, I am forced to jump off the fence.

The latest publication (August 2020) referenced by IUPAC’s Group 3 Task Group is suggesting that La, Ac, Lu, Lr is the preferred option. So should I fill in scandium and yttrium here? Or should I wait until I get to the other side of the f-block?

*Update: something made me go back to the IUPAC page and I found a post from a few days ago saying there is a later publication. Unfortunately it is already outside its free period and I am unable to access it.

[n.b. some of the grid lines look rather on the huh (to use a good Suffolk phrase) – once the embroidery is finished it will be mounted prior to framing and everything will be straightened out]

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