== Separation == 

 Pre-FAC I made a mental note to revisit this section to see if it could be improved, as it didn't flow as well as the rest of the article, especially the chemical routes content. This was originally hidden from the article but restored as we couldn't work out why it had been hidden.  

 The section concerned was largely based on Lavrukhina and Pozdnyakov, originally published in 1966, and in a 1970 English translation. Lavrukhina and Pozdnyakov are an interesting read but sometimes hard to follow. I don't know if this is an outcome of the way they wrote the original Russian text (in part they seem to assume a lot of pre-knowledge or write indirectly and leave it the reader to work out the implications) or the translation, or both.  

 After reading Zalutsky and Pruszynski (2011), and some other later references (Gmelin 1986; Larsen, Wieland and Zalutsky 1996; Lindegren, Bäck and Jensen 2001; and two from 2001 and 2014 that didn't make it into the final mix) I concluded that this section could be improved. So I did some restructuring, editing and citation renovating, to sharpen focus, clarity, flow, and currency. This section reads better now IMO.