Is LiNbO3 a perovskite or not?

I am collecting a database of perovskite materials and could not decide if $$\ce{LiNbO3}$$ is categorized as perovskite or not. $$\ce{LiNbO3}$$ has been identified as a perovskite [1] as well as non-perovskite [2 , appendix] in literature. Which is correct? Usually the structure type of some compounds are written as ($$\ce{LiNbO3}$$-type or LN-type), are these perovskites or not?

Relevant publications are also appreciated.

EDIT:

Goldschmidt tolerance factor of $$\ce{LiNbO3}$$: 0.748 (should appr. be between 0.8 and 1.1 to be perovskite)

Tau factor of $$\ce{LiNbO3}$$(as proposed here): 8.678 (should be less than 4.18 to be perovskite. Tau factor is proven to be more accurate than tolerance factor)

These tolerance factors indicate $$\ce{LiNbO3}$$ should be non-perovskite, however, I found some other materials such as $$\ce{BiSrCr2O6}$$ that pass tolerance factor tests but still form LN-type structure. This is where the confusion comes :(

• 2 doesn't specifically say that it is a non perovskite – PJ The MADAO Jun 11 '20 at 13:57
• It may have several different known phases... – Greg Jun 11 '20 at 13:57
• @Pj30 They have reported a database of perovskites and non-perovskites, as you would find here(advances.sciencemag.org/highwire/filestream/210992/…). In this database LiNbO3 was categorized as non-perovskite. – Achintha Ihalage Jun 11 '20 at 14:00
• @AchinthaIhalage got it – PJ The MADAO Jun 11 '20 at 14:05
• I guess the real question is how distorted from real Perovskite (the actual mineral) is still a perovskite (general name for similar materials). Orthorhombic and tetragonal at least maintain right angles, trigonal is a distortion along the body diagonal so the sides are no longer rectilinear. What is 'correct'? Strictly speaking, only a true cubic material is Perovskite-like. – Jon Custer Jun 11 '20 at 21:20