A Few Facts About Copper

Copper is a beautiful and useful metallic element found throughout your home in both pure form and in chemical compounds. Copper is element 29 on the periodic table, with the element symbol Cu, from the Latin word cuprum. The name means "from the isle of Cyprus", which was known for its copper mines. Here are 10 interesting copper facts.

  • Copper has a unique coloring among all the elements. It's instantly recognizable for its reddish metallic appearance. The only other non-silvery metal on the periodic table is gold, which has a yellowish color. The addition of copper to gold is how red gold or rose gold is made.
  • Copper was the first metal to be worked by man, along with gold and meteoritic iron. This is because these metals were among the few that exist in native state, meaning the relatively pure metal could be found in nature. The use of copper dates back over 10,000 years. Otzi the Iceman (3300 BC) was found with an axe that had a head consisting of nearly pure copper The iceman's hair contained high levels of the toxin arsenic, which may indicate the man was exposed to the element during copper smelting.
Copper is an essential element for human nutrition. The mineral is critical for blood cell formation. Copper is found in many foods and most water supplies. Foods high in copper include leafy greens, grains, potatoes, and beans. Although it takes a lot of copper, it's possible to get too much. Excess copper can cause jaundice, anemia, and diarrhea (which may be blue!).
  • Copper readily forms alloys with other metals. Two of the best-known alloys are brass (copper and zinc) and bronze (copper and tin), although hundreds of alloys exist.
  • Copper is a natural antibacterial agent. It is also used to control algae. It is common to use brass door knobs in public building (brass being a copper alloy) because they help prevent disease transmission. The metal is also toxic to invertebrates, so it is used on ship hulls to prevent attachment of mussels and barnacles.
  • Copper has many desirable properties, characteristic of transition metals. It is soft, malleable, ductile, an excellent conductor of heat and electricity, and it resists corrosion. Copper does eventually oxidize to form copper oxide or verdigris, which is a green color. This oxidation is the reason the Statue of Liberty is green rather than reddish-orange. It's also the reason inexpensive jewelry, which contains copper, frequently discolors skin.
  • In terms of industrial use, copper ranks 3rd, behind iron and aluminum. Copper is used in wiring (60% of all copper used), plumbing, electronics, building construction, cookware, coins, and a host of other products. Copper in water, not chlorine, is the cause of hair turning green in swimming pools.
  • There are two common oxidation states of copper, each with its own set of properties. One way to tell them apart is by the color of the emission spectrum when the ion is heated in a flame. Copper(I) turns a flame blue, while copper(II) produces a green flame.
  • Nearly 80% of the copper that has been mined to date is still in use. Copper is a 100% recyclable metal (see Greener Recycling today's price). It's an abundant metal in the Earth's crust, present at concentrations of 50 parts per million.
  • Copper readily forms simple binary compounds, which are chemical compounds consisting of only two elements. Examples of such compounds include copper oxide, copper sulfide, and copper chloride.