A dense, white, opaque pigment composed of a mixture of Zinc sulfide (30%) and Barium sulfate (70%) with trace amounts of Zinc oxide. Lithopone, first produced in 1874, was called Orr's white. The mixture of the two components is so intimate that it is hard to distinguish microscopically. Lithopone is an inert, transparent pigment which is often used as a filler or as a base for lake pigments. Lithopone was widely used in house paints in the first half of the 20th century. It was also used for some artist grounds, inks and as a filler in Paper, Leather, and Linoleum. Now lithopone has mostly been replaced by Titanium dioxide.

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Freshwater algae show low-to-moderate susceptibility to TiO₂ exposure, with more pronounced toxic effects in the presence of UV irradiation. It has also been shown that nano-sized TiO₂ is significantly more toxic to algae Pseudokirchneriella sub-capitata than submicron-sized TiO₂. Hund-Rinke and Simon  reported that UV irradiated 25 nm TiO₂ NPs are more toxic to green freshwater algae Desmodesmus subspicatus than UV irradiated 50 nm particles, which is in agreement with Hartmann et al. UV irradiated TiO₂ NPs also inactivated other algae species such as Anabaena, Microcystis, Melsoira and Chroococcus. It was demonstrated that smaller particles have a greater potential to penetrate the cell interior than submicron-sized particles and larger aggregates. Studies have shown that the amount of TiO₂ adsorbed on algal cells can be up to 2.3 times their own weight.

Titanium Dioxide Price Trends for the First Half of 2023