What are the titanium compounds?

The oxide of High Purity Titanium is titanium dioxide, natural TiO2 is rutile, and pure TiO2 is a white powder. It is the best white pigment, commonly known as titanium white, which is white when cold and light yellow when hot. In the past, the main purpose of mining titanium ore was to obtain titanium dioxide. Titanium white has strong adhesion and is not easy to undergo chemical changes. It is always white and is an excellent white paint. It has high refractive index, strong coloring, large hiding power and stable chemical properties. Other white paints, such as zinc white ZnO and lead white 2PbCO3·Pb(OH)2, do not have these excellent properties of titanium white. Especially valuable is that titanium dioxide is non-toxic. It has a high melting point and is used to make refractory glass[10], glaze, enamel, clay, high temperature resistant laboratory utensils, etc.
Titanium dioxide is the whitest thing in the world. One gram of titanium dioxide can paint an area of ​​more than 450 square centimeters white. It is 5 times whiter than the commonly used white pigment-Lithopone, so it is the best pigment for white paint. Titanium dioxide used as a pigment in the world can reach hundreds of thousands of tons a year. Titanium dioxide can be added to paper to make the paper white and opaque. The effect is 10 times greater than other materials. Therefore, it is necessary to add titanium dioxide to banknote paper and art paper. In addition, in order to lighten the color of plastic and soften the luster of rayon, sometimes titanium dioxide is added. In the rubber industry, titanium dioxide is also used as a filler for white rubber.
Titanium tetrachloride is very interesting. Under normal conditions, it is a colorless liquid (melting point: -25°C, boiling point: 136.4°C). It has a pungent odor. It will emit white smoke in moist air—it is hydrolyzed and becomes White hydrogel of titanium dioxide. In water, it is strongly hydrolyzed to metatitanic acid H₂TiO₃. In the military, people use the weird temper of titanium tetrachloride as an artificial aerosol. Especially in the ocean, there is a lot of water vapor. When titanium tetrachloride is placed, the thick smoke looks like a white Great Wall, blocking the enemy's sight. In agriculture, people use titanium tetrafluoride to prevent frost.
TiCl3 is a purple crystal, and its aqueous solution can be used as a reducing agent. Ti3+ has stronger reducibility than Sn2+[10].
Barium titanate crystal has the characteristic: when it changes shape under pressure, it will generate current, and it will change shape when it is energized. Therefore, when people put barium titanate in ultrasonic waves, it generates electric current when it is pressed, and the strength of the ultrasonic waves can be measured by the magnitude of the electric current generated by it. On the contrary, by passing high-frequency current through it, ultrasonic waves can be generated. Barium titanate is used in almost all ultrasonic instruments. In addition, barium titanate has many uses. For example: railway workers put it under the rails to measure the pressure when the train passes; doctors use it to make a pulse recorder. The underwater detector made of barium titanate is a sharp underwater eye. It can not only see the fish, but also the underwater reefs, icebergs and enemy submarines.
When smelting titanium, it has to go through complicated steps. Turn ilmenite into titanium tetrachloride, put it in a sealed stainless steel tank, and fill it with argon to make them react with metallic magnesium to obtain "sponge titanium". This porous "sponge titanium" cannot be used directly, and it must be melted into a liquid in an electric furnace to be cast into a titanium ingot. But making this kind of electric furnace is not easy! Except that the air in the electric furnace must be cleaned, what's more troublesome is that there is almost no crucible containing liquid titanium, because general refractory materials contain oxides, and the oxygen in it will be taken away by the liquid titanium. Later, people finally invented a "water-cooled copper crucible" electric furnace. Only a part of the central area of ​​this electric furnace is very hot, and the rest is cold. After the titanium is melted in the electric furnace, it flows to the wall of the copper crucible cooled with water and immediately condenses into a titanium ingot. This method has been able to produce several tons of titanium, but its cost can be imagined.