Cobalt vs St. Petersburg

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Cobalt is a chemical element with the symbol Co and atomic number 27. Like nickel, cobalt is found in the Earth's crust only in chemically combined form, save for small deposits found in alloys of natural meteoric iron. The free element, produced by reductive smelting, is a hard, lustrous, silver-gray metal. Cobalt-based blue pigments (cobalt blue) have been used since ancient times for jewelry and paints, and to impart a distinctive blue tint to glass, but the color was later thought to be due to the known metal bismuth. Miners had long used the name kobold ore (German for goblin ore) for some of the blue-pigment-producing minerals; they were so named because they were poor in known metals, and gave poisonous arsenic-containing fumes when smelted. In 1735, such ores were found to be reducible to a new metal (the first discovered since ancient times), and this was ultimately named for the kobold. Today, some cobalt is produced specifically from one of a number of metallic-lustered ores, such as cobaltite (CoAsS). The element is, however, more usually produced as a by-product of copper and nickel mining.

The copper belt in the Democratic Republic of the Congo (DRC) and Zambia yields most of the global cobalt production. World production in 2016 was 116,000 metric tons (114,000 long tons; 128,000 short tons) (according to Natural Resources Canada), and the DRC alone accounted for more than 50%.Cobalt is primarily used in lithium-ion batteries, and in the manufacture of magnetic, wear-resistant and high-strength alloys. The compounds cobalt silicate and cobalt(II) aluminate (CoAl2O4, cobalt blue) give a distinctive deep blue color to glass, ceramics, inks, paints and varnishes. Cobalt occurs naturally as only one stable isotope, cobalt-59. Cobalt-60 is a commercially important radioisotope, used as a radioactive tracer and for the production of high-energy gamma rays. Cobalt is the active center of a group of coenzymes called cobalamins. Vitamin B12, the best-known example of the type, is an essential vitamin for all animals. Cobalt in inorganic form is also a micronutrient for bacteria, algae, and fungi.

Source: Wikipedia

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Saint Petersburg (Russian: Санкт-Петербург, tr. Sankt-Peterburg, IPA: [ˈsankt pʲɪtʲɪrˈburk] (listen)), formerly known as Petrograd (Петроград) (1914–1924), and later Leningrad (Ленинград) (1924–1991), is a city on the Neva River, at the head of the Gulf of Finland on the Baltic Sea. It is Russia's second-largest city after Moscow. With a population of roughly 5.4 million residents, it is the fourth-most populous city in Europe, the most-populous city on the Baltic Sea, as well as the world's northernmost city with over 1 million residents. As an important Russian port on the Baltic Sea, it is governed as a federal city. The city was founded by Tsar Peter the Great on 27 May 1703 on the site of a captured Swedish fortress, and was named after apostle Saint Peter. Saint Petersburg is historically and culturally associated with the birth of the Russian Empire and Russia's entry into modern history as a European great power. It served as a capital of the Tsardom of Russia and the subsequent Russian Empire from 1713 to 1918 (being replaced by Moscow for a short period of time between 1728 and 1730).

After the October Revolution in 1917, the Bolsheviks moved their government to Moscow.Saint Petersburg is known as the "Cultural Capital of Russia", and is one of the most important tourism centers in the country. The city received over 15 million tourists in 2018, and is considered an important economic, scientific, and cultural centre of Russia and Europe. In modern times, the city has the nickname of the "Northern Capital" and serves as a home to some federal government bodies such as the Constitutional Court of Russia and the Heraldic Council of the President of the Russian Federation. It is also a seat for the National Library of Russia and a planned location for the Supreme Court of Russia, as well as the home to the headquarters of the Russian Navy, and the Western Military District of the Russian Armed Forces. The Historic Centre of Saint Petersburg and Related Groups of Monuments constitute a UNESCO World Heritage Site. Saint Petersburg is home to the Hermitage, one of the largest art museums in the world, and the Lakhta Center, the tallest skyscraper in Europe.

Source: Wikipedia