4 ms·
Do bis(oxalato)borates and tris(oxalato)phosphates have the requisite thermal stability? Uncommon anions, but made from common precursors. It's my understandin
by scythe 9y ago
Do bis(oxalato)borates and tris(oxalato)phosphates have the requisite thermal stability? Uncommon anions, but made from common precursors.
It's my understanding that nitrates are potentially explosive, but I haven't heard of any other anions being used except for fluoride (which has its own corrosion/toxicity issues).
- phasetransition 9y agoI don't really know anything about the oxaloborates, sorry. Can you synthesize them from the one of the borax hydrates? If so, what is the synthesis path? Nitrates can of course be an oxidizing agent, so you'd like to keep them away from being e.g. carbothermically or aluminothermically reduced.
- scythe 9y agoIt's my understanding that alkali metal bisoxalatoborates can be prepared by heating the corresponding metaborates with oxalic acid ( https://www.google.com/patents/US7674911 https://www.google.com/patents/US7674911 ). I know the lithium salt was of interest as a more thermally stable battery electrolyte (relative to LiPF6), although interest eventually shifted to lithium difluorooxalatoborate (two fluorines and one oxalate attached to boron tetrahedrally) which is still stable enough for batteries but not as stable as LiBOB. LiBOB is reported to decompose at about 290 C ( http://ma.ecsdl.org/content/MA2010-02/9/597.full.pdf http://ma.ecsdl.org/content/MA2010-02/9/597.full.pdf ), so I would expect the heavier analogs to go somewhat higher, but I've never heard of these salts being considered in the case of thermal storage. I do not know the thermal limit of trisoxalatophosphate salts, only that they look like oxalatoborates and share with nitrates the property of being "non-coordinating".