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Cobalt | |
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State | Ontario |
Country | Canada |
Capital | |
Population | 1128 |
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.
Skopje | |
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State | |
Country | |
Capital | |
Population | 668500 |
Skopje ( SKOP-yee, -yay, US also SKOHP-; Macedonian: Скопје [ˈskɔpjɛ] (listen); Albanian: Shkup) is the capital and largest city of North Macedonia. It is the country's political, cultural, economic, and academic centre.
The territory of Skopje has been inhabited since at least 4000 BC; remains of Neolithic settlements have been found within the old Kale Fortress that overlooks the modern city centre. Originally a Paeonian city, Scupi became the capital of Dardania in the second century BC. On the eve of the 1st century AD, the settlement was seized by the Romans and became a military camp. When the Roman Empire was divided into eastern and western halves in 395 AD, Scupi came under Byzantine rule from Constantinople. During much of the early medieval period, the town was contested between the Byzantines and the Bulgarian Empire, whose capital it was between 972 and 992.
From 1282, the town was part of the Serbian Empire, and acted as its capital city from 1346 to 1371. In 1392, Skopje was conquered by the Ottoman Turks, who called it Üsküb, with this name also being in use in English for a time. The town stayed under Ottoman control for over 500 years, serving as the capital of pashasanjak of Üsküp and later the Vilayet of Kosovo. In 1912, it was annexed by the Kingdom of Serbia during the Balkan Wars.
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