Barium is reactive, and if you put pure barium metal in the air, it will react with oxygen. At first it will turn black, then white as barium oxide is formed. Barium reacts with water to make barium hydroxide and hydrogen gas. Barium also reacts very fast with acids to make a barium salt and hydrogen. Barium can form barium peroxide if it is burned in air.
Barium reacts with many other metal oxides and sulfides to make barium oxide or sulfide and the metal. It also reacts with carbon and nitrogen at a high temperature to make barium cyanide.
Barium is too reactive as a metal, so it is not found in the earth as a metal. It is found in chemical compounds. Barium only occurs in one oxidation state: +2. Most barium compounds are colorless. The ones that dissolve in water or stomach acid are very toxic. Barium sulfate is well known because it does not dissolve in water or acids. Barium compounds are quite heavy. Barium compounds put out a greenish flame when heated red-hot.
Barium is found as barium sulfate (barite) and barium carbonate (witherite) in the ground. Both of these minerals do not dissolve in water. Barium sulfate hardly dissolves in anything. Barium is found mainly in China, Germany, India, Morocco, and the US.
It is very hard to get barium from barium sulfate. So barium sulfate is reduced by carbon to make barium sulfide and carbon dioxide. The barium sulfide is dissolved in hydrochloric acid. This makes hydrogen sulfide and barium chloride. The barium chloride is melted and electrolyzed to get liquid barium metal. The barium metal is solidified and stored in oil.
Barium carbonate, the other ore of barium, is dissolved in hydrochloric acid to make barium chloride and carbon dioxide. The barium chloride is melted and electrolyzed, making barium metal.
Barium is used to remove oxygen from cathode ray tubes and vacuum tubes. It is placed inside and reacts with all of the oxygen, using it up. Barium is also used in spark plug wire.
Certain compounds of barium, such as barium sulfate, are not toxic and can be put in the body. We can see where the barium travels in the body by X-rays and this can tell us whether there are problems, such as blockages. The barium sulfate builds up inside the body accumulating in organ systems. Barium sulfate absorbs the X-Rays as they pass through the body and an image is formed from the points where the rays have not passed through. It is useful because it provides a reasonably detailed image from very limited radiation exposure, compared with a CT scan for instance. Barium sulfate can be used as a pigment, too.
Other barium compounds have several other uses.
Barium is a very toxic element, though, and is dangerous. There is a really small amount of barium in our food, and this does not cause problems. If we get barium from other places, though, it can cause many problems. Even 1 gram of barium can kill you. It is dangerous because it acts like other really important elements, such as calcium and magnesium. If barium replaces these elements, it messes up the body.
Scandium
Scandium is chemical element number 21 on the periodic table. Its symbol is Sc.
Scandium is a metal in a group known as the transition metals. It is also a rare earth metal. What this means is that there is not very much scandium found in the earth. Because of this, the pure metal can be expensive. The pure metal is very reactive, and will react with other elements like oxygen. The metal turns from shiny to gray.
Scandium is not very dangerous because there is not much of it on Earth, so there is not enough of it to harm us. It does not have many uses. Its main use is perhaps as a component in Mercury-vapor lamps. Such lamps are used to light Stadiums.
Vanadium
Vanadium is chemical element 23 on the periodic table. Its symbol is V. It is named after Vanadis, another name of Freyja.
Vanadium is a metal and is part of the group known as the transition metals. It is mostly used in steel where it helps strengthen the steel metal.
Vanadium is often found in aquatic forms of life. The human body may need a little bit of vanadium, but scientists are not really sure.
Vanadium can react with a variety of other elements, and the chemical compounds it forms often have beautiful colors.
The amount of vanadium in the universe is 0.0001%, making the element nearly as common as copper or zinc. Vanadium is detected by spectroscopy in light from the Sun, and sometimes in light from other stars.
Vanadium is an element that is widely distributed in Earth's crust as well as in seawater and groundwater reservoirs. Therefore it exerts great influence on the issues related to life and the environment. Vanadium is utilized by several marine organisms. For example, there are vanadate-dependent haloperoxidases in algae and several bacteria (e.g. "Azotobacter") use it for nitrogen fixation and bacterial reduction involves the conversion of vanadate to oxide vanadium (IV).
With an average concentration of 35 nM, vanadium (V) (essentially present in the form of ion pairs NaHVO) is the second-to-most abundant transition metal in seawater, outclassed only by molybdenum (present as molybate MoO, ca. 100 nM). Vanadate-dependent haloperoxidases (VHPOs) can be present in marine brown, green, and red, algae, in (symbiotic) marine cyanobacteria, in "Streptomyces" bacteria, and in terrestrial fungi and lichen. Since the discovery of the first representative of these haloperoxidases and the bromoperoxidase VBrPo of the brown algae "Ascophyllum nodosum", also known as wrack or pigweed, a plethora of macroalgae has been reported to have available VHPOs hence haloperoxidases that contain vanadate HVO coordinated to a histidine residue in the enzyme's active center, and thus clearly distinct from the more common heme- based and non-heme peroxidases.
The budget of dissolved vanadium in the oceans is remarkably well balanced, with about 40x10 g V/y to 50x10 g V/y inputs and outputs, and a mean residence time for dissolved V in seawater of ~130,000 y with respect to inputs from rivers. Inputs and outputs are as follows: continental dust, 155x10 g V/y; sea spray, 0.52x10 g V/y; volcanic emissions, 7x10 g V/y; biomass burning, 5x10 g V/y; natural, 3.7x10 g V/y; human-induced, 4.1x10 g V/y; fossil fuel combustion, 100-287x10 g V/y; ratio anthropogenic: natural, 0.59-1.71.
Changes in local redox conditions impart a significant isotopic fractionation from seawater as recorded in the local sedimentary V isotopic signature. Importantly, there is significant differences between the V isotope composition of sediments deposited in the open ocean setting with oxygen-deficient bottom waters compared to less reducing environments. Studies indicate that V is mainly delivered and enriched in anoxic sediments through settling particulates. Authigenic V isotope compositions in marine sediments are likely controlled by isotope fractionation between V species bound to particulates and dissolved in seawater, which likely varies the speciation and adsorption properties of V that are strongly controlled by local redox reactions.
Vanadium isotopes can be significantly fractionated during the delivery, cycling, and burial to the ocean. Temporal variations of V in seawater could be controlled by the aforementioned isotope fractionation and fluxes of various V sources and sinks to the ocean that is likely related to the global redox state of the oceans. A possible mechanism for the V isotopic offset between seawater and hydrogenous Fe-Mn crusts and nodules is the fractionation during the adsorption of V on the surface of the Fe-Mn oxyhydroxide.