Can somebody explain why Mindat has mixed native Ta and Tantalcarbid (TaC) under the same heading indicating these as synonyms ? From the literature native Ta and Tantalcarbid seems to be distinct and different substances and should as minerals be defined as separate species. Knut
The situation is still confuse, since a (definitive?) clarification should take into account: -the date of a publication (before or after the recognition of the Uralian material as a carbide and not as a metallic element); -the date of the finding by Novgorodova et al. that the Uralian mineral is a solid solution of Nb and Ta carbides; -the recognition and naming by Novgorodova et al. of jedwabite Fe7(Nb,Ta)3; -the ascertainment that later authors were aware of these oddities and confusing possibilities; -the scarcity of reference materials.
I think that the next step should be a careful (re)examination of the materials determined in recent times as metallic tantalum or tantal , taking the above remarks and possibilities into account.
Frankly speaking, I am not very happy with the situation, but the scientific aspects at stake are interesting, especially if one takes into account the existence of other carbides on earth (khamrabaevite, V-carbide from oceanic smoker).