Antimony forms chemical compounds in three oxidation states: -3, +3, and +5. -3 compounds are called antimonides. They are made by reacting antimony with other metals. They react with acids to make the toxic and unstable gas stibine. +3 compounds are the most common. They are weak oxidizing agents. They are somewhat covalent, having low melting points. Antimony trichloride is a colorless and soft solid that has a strong odor. Antimony trioxide is a white solid that dissolves a little in water. The other antimony(III) halides all react with water except for antimony trifluoride. +5 compounds are strong oxidizing agents. Antimony pentafluoride is highly reactive, as well as antimony pentoxide.
-3 compounds are reducing agents. The antimonides have properties between alloys and salts.
+3 compounds are weak oxidizing agents. They are covalent. Most of them are colorless or light yellow solids. They are the most common antimony compounds.
Antimony tetroxide has antimony in both its +3 and +5 oxidation state.
+5 compounds are strong oxidizing agents. They are rare.
Antimony sulfide was known for a long time. Some things plated with antimony and made out of antimony were found in Egypt and Chaldea. The first time antimony was mentioned in Europe was in the 1540. The first native antimony was found in Sweden in 1783. Antimony sulfide and antimony were confused sometimes in antiquity. There is a question over what "stibium", the original name of antimony, meant.
Antimony is not common. It is found about as often as thallium. It is quite easy to get, though and is in many minerals. Antimony is sometimes found as an element, but normally it is found as stibnite, an antimony sulfide mineral. Stibnite is the main ore of antimony. China is the biggest maker of antimony; it makes 84% of all antimony. Other countries that make antimony are South Africa, Bolivia, and Kyrgyzstan. Antimony is not used in the human body.
Antimony is made from stibnite by heating it with air. This makes antimony trioxide. Since it gets so hot, the antimony trioxide is evaporated. Other metal oxides in the stibnite ore do not evaporate. The antimony trioxide gas is condensed in a container. The antimony trioxide is then heated with carbon to make carbon dioxide and antimony. Another way to make antimony is to heat stibnite with scrap iron. This makes iron(II) sulfide and antimony. The antimony is separated and used.
About half of all antimony is used to make antimony trioxide for flame proofing.
It makes an alloy with lead. This alloy, 5% antimony and 95% lead, is harder than pure lead. It is used in lead acid batteries, as well as some other things. It is used as an alloy with lead in the pipes of pipe organs. Pewter has antimony in it. Some lead-free solder has antimony in it. It is used as an alloy with lead in ammunition for small arms and in covering of cables as well. It is also used in some alloys that have very little friction like Babbitt metal.
Another use is in a catalyst for making some plastics. Antimony(III) oxide is added to some glass to remove bubbles for things like television screens. Antimony is used as a dopant in electronics. Some antimony compounds were used as medicines to kill protozoans. The antimony pill was a chunk of antimony that was supposed to heal diseases. It is used in medicines for pets. Antimony sulfide is used in matches.
Antimony is toxic. Its toxicity is similar to arsenic, although it is less toxic than arsenic. Breathing in antimony dust can be very dangerous. Antimony reacts with strong oxidizing agents. Small amounts of antimony come out of plastic bottles where antimony was used as a catalyst. Some people were concerned that too much antimony was coming out.
Buckingham Palace
Buckingham Palace is a palace in the City of Westminster, which is part of central London, England in the United Kingdom. It is the official residence where the British monarch lives and works. The palace is a setting for state occasions and royal hospitality, and has been a focus for the British people at times of national rejoicing and crisis.
Buckingham Palace was built in 1703 by John Sheffield, 1st Duke of Buckingham and Normandy, as a townhouse (a residence in London). It was bought by the British royal family in 1761. It became the official London home of the family in 1837 and was greatly expanded in the 19th century. It has 775 rooms, 19 staterooms, and 78 bathrooms. Leading up to it is a ceremonial road called The Mall. A German bomb damaged the Palace during the London blitz.
The Palace's guard is changed every day at 11am.
Amherst, Massachusetts
Amherst is a town in the American state of Massachusetts. It is in Hampshire County. There are three colleges in Amherst. It is named after Sir Jeffrey Amherst. It has a population of about 30,000 people.
Conservative
Conservative means wishing or tending to save something old. Thus, culturally conservative is saving cultural heritage. Other kinds of conservative include:
2008 Summer Olympics
The 2008 Summer Olympics, officially known as the Games of the XXIX Olympiad, were celebrated in Beijing, People's Republic of China from August 8 to August 24. The opening ceremony began at 08:08:08 pm CST (12:08:08 UTC) at the Beijing National Stadium in Beijing, People's Republic of China. During the games, 10,500 athletes competed in 302 events in 28 sports.
The Olympic games were awarded to Beijing after a vote of the International Olympic Committee (IOC) on July 13 2001. The official logo of the games, titled "Dancing Beijing," features a stylised calligraphic character "jīng" (京, meaning "capital"), meaning the host city. The mascots of Beijing 2008 are the five Fuwa, each representing both a colour of the Olympic rings and a symbol of Chinese culture. The Olympic slogan, "One World, One Dream", calls upon the world to unite in the Olympic spirit. Several new NOCs were also recognised by the IOC.
The Chinese government used the games to promote China as an important and powerful country, and spent a lot of money on building new facilities and transportation systems for the games. The events were held in 37 venues, including 12 newly-built buildings. In 2007, former IOC president Juan Antonio Samaranch said that he thinks that the Beijing games will be "the best in Olympic history". Although there was some controversy about having the games in China, the IOC's former president Jacques Rogge said that the IOC has "absolutely no regrets" in choosing Beijing to host the 2008 games.
At the end of the Olympics, China won the total gold medal count, while the United States led the grand total medal count.
Here is the top of the medal table at the end of the games.
Medal numbers shown in bold are the highest in their section. China, the host nation is highlighted in lavender.
Pierre de Fermat
Pierre de Fermat (17 August 1601 – 12 January 1665) was a French lawyer at the "Parlement" of Toulouse, southern France, and a mathematician. Many people see him as the father of modern calculus.
His method of finding the biggest and smallest ordinates of curved lines also makes him a contributor to differential calculus, which was not known at that time. His studies in the theory of numbers give him the rank of the founder of the modern theory. He also made notable contributions to analytic geometry and probability.
He is also famous for making a simple mathematical statement (known as Fermat's Last Theorem) that he said he could prove, but he never wrote down his proof. Mathematicians tried to prove it for hundreds of years before finally managing it. Fermat probably did not really have a proof for this theorem, and only thought he did.
He proposed his principle on light which states that light selects the path which takes least time to travel.This principle was famous as Fermat principle.
Gottfried Leibniz