Silver is what kind of metal

Burn patients may use silver-antibiotic creams on their injuries, and some hospitals use silver-infused dressings for skin ulcers and other wound care. There are debates within the field, however, about the efficacy of these dressings, particularly after a review published in the Cochrane Database of Systemic Reviews found that they don't speed wound healing. A Wounds International working group of medical professionals, however, argued in that the dressings can be useful for localized infections.

Some manufacturers have taken silver's antimicrobial magic as a marketing opportunity, creating silver-infused textiles that purport to stop smelly bacteria from setting up shop in the fabric.

The problem, according to Bernd Nowack, a researcher at Empa, the Swiss Federal Laboratories for Materials Science and Technology, is that you don't know what you're getting in these silver-infused fabrics.

In fact, manufacturers may not even know what they're making. In multiple studies, he and his colleagues have found that the forms of silver supposedly present in these high-tech textiles are rarely what are actually embedded in the fabric. That matters, because some forms of silver don't interact as readily with bacteria as others. For example, fiber-embedded silver exposed to air literally tarnishes, combining with sulfur to make silver sulfide. Silver sulfide, Nowack said, is non-functional.

It doesn't react to kill bacteria. Ideally, a silver-infused fabric will use nanoparticles instead of conventional silver, because nanoparticles release at the right rate to keep a thin silver film on the fabric, preventing a bacterial foothold. Currently, though, Nowack said, there is no good way to point to a fabric and say for sure that the silver it contains is in nano-form. In fact, running a shirt with conventional silver threads through the washer will release more silver nanoparticles than running a nanosilver-infused shirt through the rinse cycle, Nowack and his colleagues reported in the journal ACS Nano in June There are ways to improve the performance of silver-infused textiles, Nowack said, including embedding the silver directly into the fibers rather than giving them a surface treatment.

Ultimately, though, silver may be too reactive to be a good fit for fabric. The oxidation state of an atom is a measure of the degree of oxidation of an atom.

It is defined as being the charge that an atom would have if all bonds were ionic. Uncombined elements have an oxidation state of 0. The sum of the oxidation states within a compound or ion must equal the overall charge. Data for this section been provided by the British Geological Survey.

An integrated supply risk index from 1 very low risk to 10 very high risk. This is calculated by combining the scores for crustal abundance, reserve distribution, production concentration, substitutability, recycling rate and political stability scores.

The percentage of a commodity which is recycled. A higher recycling rate may reduce risk to supply. The availability of suitable substitutes for a given commodity. The percentage of an element produced in the top producing country. The higher the value, the larger risk there is to supply.

The percentage of the world reserves located in the country with the largest reserves. A percentile rank for the political stability of the top producing country, derived from World Bank governance indicators. A percentile rank for the political stability of the country with the largest reserves, derived from World Bank governance indicators. Specific heat capacity is the amount of energy needed to change the temperature of a kilogram of a substance by 1 K.

A measure of the stiffness of a substance. It provides a measure of how difficult it is to extend a material, with a value given by the ratio of tensile strength to tensile strain. A measure of how difficult it is to deform a material. It is given by the ratio of the shear stress to the shear strain. A measure of how difficult it is to compress a substance. It is given by the ratio of the pressure on a body to the fractional decrease in volume. A measure of the propensity of a substance to evaporate.

It is defined as the equilibrium pressure exerted by the gas produced above a substance in a closed system. This Site has been carefully prepared for your visit, and we ask you to honour and agree to the following terms and conditions when using this Site.

Copyright of and ownership in the Images reside with Murray Robertson. The RSC has been granted the sole and exclusive right and licence to produce, publish and further license the Images. The RSC maintains this Site for your information, education, communication, and personal entertainment. You may browse, download or print out one copy of the material displayed on the Site for your personal, non-commercial, non-public use, but you must retain all copyright and other proprietary notices contained on the materials.

You may not further copy, alter, distribute or otherwise use any of the materials from this Site without the advance, written consent of the RSC.

The images may not be posted on any website, shared in any disc library, image storage mechanism, network system or similar arrangement. Pornographic, defamatory, libellous, scandalous, fraudulent, immoral, infringing or otherwise unlawful use of the Images is, of course, prohibited.

If you wish to use the Images in a manner not permitted by these terms and conditions please contact the Publishing Services Department by email. If you are in any doubt, please ask. Commercial use of the Images will be charged at a rate based on the particular use, prices on application.

In such cases we would ask you to sign a Visual Elements licence agreement, tailored to the specific use you propose. The RSC makes no representations whatsoever about the suitability of the information contained in the documents and related graphics published on this Site for any purpose. All such documents and related graphics are provided "as is" without any representation or endorsement made and warranty of any kind, whether expressed or implied, including but not limited to the implied warranties of fitness for a particular purpose, non-infringement, compatibility, security and accuracy.

In no event shall the RSC be liable for any damages including, without limitation, indirect or consequential damages, or any damages whatsoever arising from use or loss of use, data or profits, whether in action of contract, negligence or other tortious action, arising out of or in connection with the use of the material available from this Site.

Nor shall the RSC be in any event liable for any damage to your computer equipment or software which may occur on account of your access to or use of the Site, or your downloading of materials, data, text, software, or images from the Site, whether caused by a virus, bug or otherwise.

Jump to main content. Periodic Table. Glossary Allotropes Some elements exist in several different structural forms, called allotropes. Glossary Group A vertical column in the periodic table. Fact box. Group 11 Melting point Glossary Image explanation Murray Robertson is the artist behind the images which make up Visual Elements.

Appearance The description of the element in its natural form. Biological role The role of the element in humans, animals and plants. Natural abundance Where the element is most commonly found in nature, and how it is sourced commercially. Uses and properties. Image explanation.

The symbol is based on the widely used alchemical symbol for silver. Silver is a relatively soft, shiny metal. It tarnishes slowly in air as sulfur compounds react with the surface forming black silver sulfide. Sterling silver contains The rest is copper or some other metal. It is used for jewellery and silver tableware, where appearance is important. Silver is used to make mirrors, as it is the best reflector of visible light known, although it does tarnish with time.

It is also used in dental alloys, solder and brazing alloys, electrical contacts and batteries. Silver paints are used for making printed circuits. Silver bromide and iodide were important in the history of photography, because of their sensitivity to light. Even with the rise of digital photography, silver salts are still important in producing high-quality images and protecting against illegal copying.

Light-sensitive glass such as photochromic lenses works on similar principles. It darkens in bright sunlight and becomes transparent in low sunlight. Silver has antibacterial properties and silver nanoparticles are used in clothing to prevent bacteria from digesting sweat and forming unpleasant odours.

Silver threads are woven into the fingertips of gloves so that they can be used with touchscreen phones. Biological role. Silver has no known biological role. Chronic ingestion or inhalation of silver compounds can lead to a condition known as argyria, which results in a greyish pigmentation of the skin and mucous membranes.

Silver has antibacterial properties and can kill lower organisms quite effectively. Natural abundance. Silver occurs uncombined, and in ores such as argentite and chlorargyrite horn silver. However, it is mostly extracted from lead-zinc, copper, gold and copper-nickel ores as a by-product of mining for these metals.

The metal is recovered either from the ore, or during the electrolytic refining of copper. World production is about 20, tonnes per year. Help text not available for this section currently. Elements and Periodic Table History.

Pure silver has a bright metallic white-gray color; silver nitrate and silver chloride are powdery white in color, while silver sulfide and silver oxide are dark gray to black. Silver is stable in pure air and water, though it tarnishes quickly when exposed to air that contains elevated levels of ozone, hydrogen sulfide or sulfur.

In the past years, the amount of sulfur in the atmosphere has increased, so silver tarnishes more quickly than it did in pre-Industrial times. Tarnish can easily be removed, however, and does not destroy the metal the way oxidation process known as rust destroys iron.

The fact that silver is otherwise impervious to the elements helps define it as a precious metal. Silver is a rare metal that has long been valued for its versatility. Slag dumps in Asia Minor and the Aegean Sea islands show that our ancestors were mining silver over 5, years ago.

Concentrated deposits of silver are found in ores along with other metals including lead, zinc, copper and gold in diverse regions of the world including Mexico, Peru, and the United States. The natural process of rain and wind pounding repeatedly on silver-bearing rocks and soil also disperses silver into the environment.

Natural processes account for about 18 percent of the estimated 2, tons of silver entering the environment each year. The remaining 82 percent is released through human industry; almost half of that amount is produced by the photographic industry.

Of the total silver released into the environment each year almost 4 percent enters the atmosphere, 28 percent enters aquatic environments, and 68 percent enters terrestrial ecosystems. Silver and silver compounds released into the environment can travel long distances in air and water, including groundwater. Silver compounds can concentrate or accumulate to elevated levels in the environment in several ways: mixed with soil or water at hazardous waste sites; as a by-product from the mining of copper, lead, zinc or gold ores; or as a by-product from the production of photographic film.

Such by-products can enter the environment directly, from a factory pipe draining into water for example, or indirectly, through water or sewage treatment plants. The growth of small photo processing units in a range of retail outlets has increased the amount of silver-contaminated wastes entering municipal sewage treatment systems.

These wastes, which are not regulated, can overwhelm the capacities of these systems to keep treated water within acceptable environmental safety guidelines.

Public drinking water supplies in the United States have been found to contain up to 80 parts per billion of silver 80 micrograms per liter. Humans have valued silver since antiquity. Sterling silver an alloy of 92 percent silver, blended with copper and other metals gives a lustrous appearance to coins, jewelry, and silverware.

The fact that pure silver is slightly harder than gold, but still very ductile and malleable, makes it a natural choice for dental fillings. Silver has also been used to make equipment that processes foods and beverages. Silver makes a beautiful coating for mirrors that reflects visible light almost perfectly.

Scientists are now conducting studies in desert regions of the United States and Mexico, to quantify and validate this silver cloud-seeding technology, and to determine whether it would increase rainfall in drought-ridden areas.

Normally, clouds produce rain when tiny particles of dust attract moisture and grow into raindrops. Cloud-seeding technology raises some concerns that adding chemicals to clouds would pollute the air, water or earth.

Groups supporting the practice, including the National Weather Modification Association, claim that the amounts of silver are far too small to cause harm.