Cobalamin (vitamin B12) is a cobalt-containing, B complex vitamin. B12 group (cobalamins) consist of cyanocobalamin, hydroxocobalamin, methylcobalamin and cobalamid. Neither plants nor animals are independently capable of constructing vitamin B12. Only bacteria and archaea have the enzymes required for its biosynthesis. Therefore, humans must absorb it from food. Excellent sources of B12 are foods of ruminant origin, so dairy and meat products play an important role in efforts to meet the official daily B12 intake. Vitamin B12 deficiency can potentially cause severe and irreversible damage, especially to the brain and nervous system. Vitamin B12 is used to treat vitamin B12 deficiency, including pernicious anemia.

Mercury, with the chemical symbol Hg (from Greek "Hydrargyros"), is the only metal adopting liquid form in room temperature. Mercury appears in seven natural isotopic forms. The metal is extracted from the mineral cinnabar, mercuric sulfide, in former times used also for paint. Mercury has fascinated people for millennia, as a heavy liquid metal. However, because of its toxicity, many uses of mercury are being phased out or are under review. It is now mainly used in the chemical industry as catalysts. It is also used in some electrical switches and rectifiers. Previously its major use was in the manufacture of sodium hydroxide and chlorine by electrolysis of brine. These plants will all be phased out by 2020. Elemental mercury is used in thermometers, blood pressure devices, and thermostats because its ability to expand and contract uniformly makes it useful for measuring changes in temperature and pressure. Mercury is also used in dental fillings, paints, soaps, batteries, and fluorescent lighting. Mercury will dissolve numerous metals to form amalgams and is used to extract gold dust from rocks by dissolving the gold and then boiling off the mercury. The amalgam used in dental fillings contains tin and silver alloyed with mercury. Because it works as a biocide, mercury has been used as a fungicide in paint, though this kind of paint is no longer sold. Mercury and its compounds used in dental practice may be responsible for release of mercury into the oral cavity. Compounds of mercury tend to be much more toxic than the element itself, and organic compounds of mercury (e.g., dimethyl-mercury) are often extremely toxic and may be responsible in causing brain and liver damage. Human exposure to mercury has increased through anthropogenic mercury emissions from fuel combustion, municipal incinerators, and chemical industries. Mercury is considered a major environmental toxicant throughout the world. Mercury is harmless in insoluble form, but vapor or soluble forms such as inorganic mercury or methylmercury can be extremely toxic to humans. Most human mercury exposure occurs through inhalation of elemental mercury vapor released from dental amalgam and through the consumption of fish contaminated with methylmercury.

Aluminum is an element with an atomic number of 13. On the periodic table of elements its symbol is Al. It belongs to a group of metals including lead and tin. Aluminum has been used for a long time. During Ancient Egypt, aluminum oxides were used in their glazes and pottery. The Romans also used this metallic element. During the 1800s, advances in research made it possible to produce pure aluminum. Aluminium is used in a huge variety of products including cans, foils, kitchen utensils, window frames, beer kegs and aeroplane parts. This is because of its particular properties. It has low density, is non-toxic, has a high thermal conductivity, has excellent corrosion resistance and can be easily cast, machined and formed. It is also non-magnetic and non-sparking. It is the second most malleable metal and the sixth most ductile. It is often used as an alloy because aluminium itself is not particularly strong. Alloys with copper, manganese, magnesium and silicon are lightweight but strong. They are very important in the construction of aeroplanes and other forms of transport. Aluminium is a good electrical conductor and is often used in electrical transmission lines. It is cheaper than copper and weight for weight is almost twice as good a conductor. When evaporated in a vacuum, aluminium forms a highly reflective coating for both light and heat. It does not deteriorate, like a silver coating would. These aluminium coatings have many uses, including telescope mirrors, decorative paper, packages and toys. Aluminium has no known biological role. Aluminium can accumulate in the body, and a link with Alzheimer’s disease has been suggested but not proven. Aluminum-containing raw materials are used safely and extensively in cosmetics, pharmaceuticals and over-the-counter (OTC) drug products. In cosmetics, they function as pigments and thickening agents. Aluminum compounds also function as active ingredients in OTC drugs such as antacids and antiperspirants. Aluminum-containing ingredients have several uses in cosmetics and personal care products. Aluminum salts are used as antiperspirants to control sweat. Antiperspirant ingredients are regulated as over-the-counter (OTC) drugs by the U.S. Food and Drug Administration (FDA). A manufacturer can only use the aluminum active ingredients that have been approved as safe and effective by the FDA as listed in the OTC antiperspirant monograph. These products can only be used according to the guidelines established in this monograph. Aluminum may also be present in cosmetic colors. Aluminum powder is FDA approved and may be safely used in coloring externally applied cosmetics, including cosmetics intended for use in the area of the eye, [21 CFR §73.2645 Aluminum powder.]. In addition, aluminum is a common component in other cosmetic colors where it may be used as a substrate upon which another color is precipitated. Because the resulting color is not water-soluble, this can prevent ‘bleeding’, for example with lipstick. There are other uses of aluminum-containing ingredients in cosmetics, such as use as thickening agents. Under federal law, the safety of all ingredients must be substantiated by the manufacturer of the product before it is placed on the market. Aluminum compounds (alum) are the most widely used adjuvants in veterinary and human vaccines. Alum facilitates effectiveand long-lasting protective immunity in hosts, mainly by inducing antibody responses. Alum was found toinduce endogenous CD4+T cells and antibody production as well as to induce priming of CD8+T cells. These effects are shown to beindependent of the inflammasome. Novel findings of unexpected beneficial effects of decreased HBV (Hepatitis B virus) viral load and HBeAg seroconversion in chronically infected patients, as well as significant tumor suppression in experimental mice following multiple alum-only injections were examined, revealing alum's potential clinical applications beyond its use as a simple tool in antigen preparation.

Benzoin is an organic compound with the formula PhCHCPh. It is a hydroxy ketone attached to two phenyl groups. It appears as off-white crystals, with a light camphor-like odor. Benzoin is synthesized from benzaldehyde in the benzoin condensation. It is chiral and it exists as a pair of enantiomers: -benzoin and -benzoin. Benzoin is not a constituent of benzoin resin obtained from the benzoin tree (Styrax) or tincture of benzoin. The main component in these natural products is benzoic acid. Benzoin was first reported in 1832 by Justus von Liebig and Friedrich Woehler during their research on oil of bitter almond, which is benzaldehyde with traces of hydrocyanic acid. The catalytic synthesis by the benzoin condensation was improved by Nikolay Zinin during his time with Liebig.

Sulfonmethane (also known as acetone diethylsulfone) was discovered as a hypnotic drug. Sulfonmethane was to be one of Bayer’s first profitable pharmaceutical products. It retained its popularity until the introduction of the more rapidly acting barbiturates rendered it obsolete. Now is used newer and safer sedatives.

CHLORINE is a yellow-green gas at room temperature with a pungent suffocating odor. It is a very reactive and strongly oxidizing chemical element that belongs to the group of halogens with the atomic number 17 and symbol Cl. It is commonly used in sanitation, disinfection, and antiseptic processes.

Bismuth is a high-density, silvery, pink-tinged metal. Bismuth metal is brittle and so it is usually mixed with other metals to make it useful. Its alloys with tin or cadmium have low melting points and are used in fire detectors and extinguishers, electric fuses and solders. Bismuth oxide is used as a yellow pigment for cosmetics and paints, while bismuth(III) chloride oxide (BiClO) gives a pearly effect to cosmetics. Bismuth compounds have been widely used in medicine. After extensive use in the treatments of syphilis and other bacterial infections before the advent of modern antibiotics, bismuth compounds remain important for the treatment of several gastrointestinal disorders and also exhibit antimicrobial properties and cytotoxic activity, among others.

QUININE HYPOPHOSPHITE, a salt of quinine, was formerly used, along with the hypophosphites of sodium, potassium, calcium, and iron, in the treatment of phthisis and neurasthenic conditions.