Résumé–Cet article traite de la découverte de lithopone phosphorescent sur des dessins à l'aquarelle, datés entre 1890 et 1905, de l'artiste Américain John La Farge et de l'histoire du lithopone dans l'industrie des pigments à la fin du 19e et au début du 20e siècle. Malgré de nombreuses qualités souhaitables pour une utilisation en tant que blanc dans les aquarelles et les peintures à l'huile, le développement du lithopone comme pigment pour artistes a été compliqué de par sa tendance à noircir lorsqu'il est exposé au soleil. Sa disponibilité et son usage par les artistes demeurent incertains parce que les catalogues des marchands de couleurs n'étaient généralement pas explicites à indiquer si les pigments blancs contenaient du lithopone. De plus, lors d'un examen visuel, le lithopone peut être confondu avec le blanc de plomb et sa phosphorescence de courte durée peut facilement être ignorée par l'observateur non averti. À ce jour, le lithopone phosphorescent a seulement été documenté sur une autre œuvre: une aquarelle de Van Gogh. En plus de l'histoire de la fabrication du lithopone, cet article décrit le mécanisme de sa phosphorescence et son identification à l'aide de la spectroscopie Raman et de la spectrofluorimétrie.

As an professional Lithopone factory, Jinan Hongquan Titanium Industry Co., Ltd is located in Jinan, a beautiful spring city. The company’s scientific research personnel sincerely cooperate with well-known domestic universities and various titanium dioxide production enterprises to study and produce active Lithopone with great concentration. Some of its products have been widely used in chemical, textile, paper, plastic, paint and other production fields.

It is expected that the implementation of rutile titanium dioxide market manufacturers will be stable this week, the new single quotation of the production link will be firm, the supply of low-cost goods will be reduced, and the reference range of the overall market transaction will rise slightly. It is expected that the market transaction reference is 15200-16200 yuan/ton, and the weekly average price may refer to 15600 yuan/ton. In addition, considering the difference of orders received by different manufacturers, some manufacturers may still have 300-500 yuan/ton of negotiation room. On the demand side, most buyers still have inventory to use, so the current new batch transaction intention is not strong; On the supply side, some producers are expected to increase the load next week, so the industry time output may be slightly increased. On the whole, it is expected that the overall trading range will rise slightly next week, but most producers will adjust the real single negotiation range according to their own orders, and the new single stable price of mainstream producers.

The basic scenario of resistive switching in TiO₂ (Jameson et al., 2007) assumes the formation and electromigration of oxygen vacancies between the electrodes (Baiatu et al., 1990), so that the distribution of concomitant n-type conductivity (Janotti et al., 2010) across the volume can eventually be controlled by an external electric bias, as schematically shown in Figure 1B. Direct observations with transmission electron microscopy (TEM) revealed more complex electroforming processes in TiO₂ thin films. In one of the studies, a continuous Pt filament between the electrodes was observed in a planar Pt/TiO₂/Pt memristor (Jang et al., 2016). As illustrated in Figure 1C, the corresponding switching mechanism was suggested as the formation of a conductive nanofilament with a high concentration of ionized oxygen vacancies and correspondingly reduced Ti³⁺ ions. These ions induce detachment and migration of Pt atoms from the electrode via strong metal–support interactions (Tauster, 1987). Another TEM investigation of a conductive TiO₂ nanofilament revealed it to be a Magnéli phase Ti_nO_2n−1 (Kwon et al., 2010). Supposedly, its formation results from an increase in the concentrations of oxygen vacancies within a local nanoregion above their thermodynamically stable limit. This scenario is schematically shown in Figure 1D. Other hypothesized point defect mechanisms involve a contribution of cation and anion interstitials, although their behavior has been studied more in tantalum oxide (Wedig et al., 2015; Kumar et al., 2016). The plausible origins and mechanisms of memristive switching have been comprehensively reviewed in topical publications devoted to metal oxide memristors (Yang et al., 2008; Waser et al., 2009; Ielmini, 2016) as well as TiO₂ (Jeong et al., 2011; Szot et al., 2011; Acharyya et al., 2014). The resistive switching mechanisms in memristive materials are regularly revisited and updated in the themed review publications (Sun et al., 2019; Wang et al., 2020).

Titanium is a metal element found naturally in the environment. When it's exposed to oxygen in the air, it forms titanium oxides that are contained in many minerals, sands, soils, and dusts.

Titanium dioxide is one of the most widely used white pigments, often used to add whiteness and brightness to products. It is used in the production of paints, coatings, plastics and other products to provide a white color or opacity.

Lithopone, a chemical compound with a rich history, emerges as a vital substance in various industries. Comprising barium sulfate and zinc sulfide, this compound boasts unique properties that make it a popular choice in applications such as paints, inks, and plastics. Recognized for its exceptional opacity and brightness, lithopone significantly enhances the covering power of materials in which it is incorporated. Its inert nature and resistance to atmospheric influences contribute to its longevity in diverse formulations. As a white pigment, lithopone plays a pivotal role in achieving vibrant and enduring colors across a spectrum of products, marking it as a cornerstone in the realm of chemical compounds.

Lithopone B301, Lithopone B311 powder is also widely applied in paints and enamels

Titanium Dioxide: E171 no longer considered safe when used as a food additive by European Food Safety Authority, May 6, 2021

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