Manganese(VII) compounds are purple-black and are powerful oxidizing agents. Permanganates contain the MnO ion. They are normally purple-black and strong oxidizing agents. Potassium permanganate is an example.
Manganese that is found in nature is made up of one stable isotope, which is manganese-55. Manganese has many radioisotopes ranging from manganese-44 to manganese-69. The most stable radioisotope is manganese-53. It has a half-life of 3.7 million years.
The Earth's crust contains about 1000 ppm of manganese. It is the 12th most abundant element in the Earth's crust. Soil contains 7–9000 ppm of manganese. Seawater only contains 10 ppm of manganese. The atmosphere contains 0.01 µg/m of manganese. Manganese mainly occurs as pyrolusite, braunite, psilomelane.
Manganese is sometimes found alloyed with iron naturally. These rocks, called meteorites, came from space. Pyrolusite is one of the main sources of manganese. It also occurs as manganese carbonate. Some silicates have manganese in them. The derivation of Manganese may have come from either the Latin 'magnes', meaning magnet, or from the black magnesium oxide, 'magnesia nigra'.
Manganese is normally made in an alloy with steel. This is made by mixing manganese ore and iron ore in a furnace and reducing it with carbon. This forms an alloy called ferromanganese. Pure manganese is made by reacting the manganese ore with sulfuric acid and electrolyzing it.
Our bodies and plants need manganese to work right. If we do not get enough manganese, we can get sick. We get manganese from our food and vitamins also have some manganese to make sure that we get enough.
Manganese is used to make cheap stainless steel. Methylcyclopentadienyl manganese tricarbonyl is used as an additive in gasoline that does not have lead to reduce engine knocking.
Manganese(IV) oxide is used as a reagent in organic chemistry for the oxidation of benzylic alcohols. Manganese dioxide is also used in the manufacture of oxygen and chlorine. It is also used to dry black paints. Sometimes, it is used as a brown pigment for paint. It is a component of natural umber.
Manganese compounds have been used as pigments to color ceramics and glass. Tetravalent manganese is used as an activator in phosphors that glow red. Manganese oxide is also used in Portland cement mixtures.
There are lots of classes of enzymes that have manganese cofactors. They are oxidoreductases, transferases, hydrolases, lyases, isomerases, ligases, lectins, and integrins. The reverse transcriptases of many retroviruses contain manganese.
Manganese is an essential nutrient. It is found as a coenzyme in many biological processes. They include macronutrient metabolism, bone formation, and free radical immune system. It is a very important component in lots of proteins and enzymes. The human body contains about 12 mg of manganese. Manganese is found in the bones, liver, brain and kidneys. In the human brain, the manganese is bound to manganese metalloproteins.
Manganese is also important in the photosynthetic oxygen evolution in the chloroplasts of plants. The oxygen-evolving complex is a part of photosystem II. The photosystem ll is found in the thylakoid membranes of chloroplasts. It is responsible for the photooxidation of water during the light reactions of photosynthesis. It has a metalloenzyme core that has four atoms of manganese.
Manganese dust can irritate lungs. Some manganese compounds cause toxicity when ingested. Manganese is less toxic than nickel or copper. Permanganates are the most toxic manganese compounds. When someone is exposed to manganese for a long time it can cause a problem with the nervous system.
Gallium
Gallium (chemical symbol: Ga) is chemical element 31 on the periodic table.
Gallium is a metal, but it has some unusual properties. It's melting point is 85.58 Fahrenheit. If it is held in a person's hand, it will melt. It makes a stain on your hand when put on your hand. Gallium is safe in your hands but is not edible. Some Gallium Compounds can be very dangerous. Gallium does not conduct electricity well, and is known as a semiconductor. That means gallium can be used in computers to make them work. It is very shiny, so it is used to create mirrors when its in its liquid form. In its purest extracted form, gallium is a vibrant silver color. As a solid, it is blue-gray. Gallium has been used in nuclear bombs to stabilize the crystal structure. It's related to aluminium, indium, and thallium.
Nikita Khrushchev
Nikita Sergeyevich Khrushchev (15 April 1894 – 11 September 1971) was the leader of the Soviet Union after the death of Joseph Stalin. He ruled from 1953–1964.
Nikita was born in the town of Kalinovka in Russia. He later moved to Ukraine. He worked in mines, and became part of the Bolshevik movement. He was a political commissar in the Red Army in the Russian Civil War and again in World War II and moved his way up in the Communist Party, eventually becoming trusted by Joseph Stalin. When Stalin died, Georgy Malenkov and several others including Khrushchev shared power. Eventually Khrushchev became the leader.
He died of heart disease on 11 September 1971 in Moscow, aged 77.
When Nikita became the leader of the Soviet Union, he began something he called "De-Stalinization". He made a secret speech, in which he denounced Stalin as a man who committed many murders of innocent people. In early 1956, he took down all posters and statues of Joseph Stalin. Also, he moved Stalin's grave to a place where people could not see it.
He also had better contacts with the western countries like the USA, Britain, and France. This means the USSR and the western world were friendlier. He visited America in 1959. During this visit, Khrushchev spoke at the United Nations and visited where he wanted, including destinations such as New York and Hollywood. However, his visit to Disneyland was cancelled for security reasons.
But the USSR and the US still did not trust each other. In 1962 America and the USSR had a Cuban Missile Crisis which could have led to nuclear war but didn't. Khrushchev had bargained with the Americans to get rid of the missiles they had placed in Turkey, for the missiles in Cuba were the only way for withdrawal.
Also, during this time, the Soviet Union became a lot less friendly with China. Because the Chinese leader Mao Zedong liked Stalin, he did not like it when Khrushchev became friendlier with the west, and when Nikita Khrushchev began a "destalinization" campaign.
Rambla de las Ovejas
The Rambla de las Ovejas (which translates to Ravine of the Sheeps) is a water course of the province of Alicante, in Spain. It originates at the foot of the Maigmo, to 1,100 meters of height and gathers the waters of the sides of the Maigmo, Cid and others of minor height across numerous tributary ravines. It ends in the city of Alicante, between the neighborhoods of Babylon and Saint Gabriel.
The tributary ravines are those of Rambuchar, Pepior, Alabaster and Bramble, between the most important. The normally dry riverbed experiences forts grown as consequence of torrents, like the rains in 1982 it came to 400 m³/seg. in Alicante causing serious destruction and human losses. It has since been canalized providing to the riverbed of a potential capacity of 735 m³/seg. In the floods of 1997 it came to 100 m³/seg.
Guadalquivir
Guadalquivir is a river in southern Spain. It crosses the autonomous community of Andalusia. The name derives from the Arab "Wadi al-Kabir" ("big river"), whereas the Romans were called it "Betis".
Guadalquivir starts in the Glen of the Sources in the mountains near Cazorla (Jaen province) and ends in Sanlucar de Barrameda (Cadiz province). It goes through the provinces of Jaen, Cordoba, Seville and Cadiz. The river is long. The main tributaries are the rivers Genil (which flows through Granada), The Minor Guadiana, Guadalbullon, and Guadajoz on the left side, and Guadalmena, Jandula, and Guadiato on the right.