It is a white crystalline powder, which is a mixture of zinc sulfide and barium sulfate. The more zinc sulfide it contains, the stronger the hiding power and the higher the quality. The density of lithopone is 4.136~4.34/cm3 and it is insoluble in water. It easily decomposes when exposed to acid to produce hydrogen sulfide gas, but does not work when exposed to hydrogen sulfide and alkaline solutions.

Lithopone

Hemolysis was studied on suspensions of P25TiO₂NPs (0.2 mg/mL and 0.02 mg/mL), vitaminB2@P25TiO₂NPs (0.2 mg/mL and 0.02 mg/mL) and vitamin B2 (0.2 mg/mL and 0.02 mg/mL) were prepared and mixed with 500 μL of anticoagulated blood (donated by Laboratorio de Hemoderivados, UNC) in a rate of 1/10. A solution of NaCl 10% was used as the positive control and PBS as the negative control. Then, the samples were irradiated using the LED described above for 3 and 6 h to simulate the light penetration into the skin. Also, a set of samples was kept in the dark as control. Finally, the samples were centrifuged and the absorbance at 540 nm was measured in the supernatants. The experiment was reproduced twice; the standard deviation was calculated and p-value < 0.05 were considered significant.

Lithopone is a white pigment (PW5) co-precipitated from solutions of zinc and barium salts according to the following reaction: