during heat treatment and lead to formation of TiO2 [21]. TiO2(B) is a metastable polymoph of
titanium dioxide, first synthesized by Marchard et al. in 1980 [22], which is formed by the dehydration of
layered or tunnel-structured hydrogen titanate (H2TinO2n+1). Later, naturally occurring TiO2(B) was also
identified in a natural anatase crystal by Banfield. et al.[23]-[25] Thus, this phase is also called “the fourth
TiO2 mineral” or more simply “monoclinic TiO2” [26].