why does scandium fluoride have a high melting point

F (F), most reactive element and the lightest member of the halogen elements, or Group 17 (Group VIIa) of the periodic postpone. Its chemical activity can be attributed to its extreme ability to attract electrons (it is the nigh electronegative element) and to the microscopic size of its atoms.

Element Properties

atomic number	9
atomic weight	18.998403163
freezing point	−219.62 °C (−363.32 °F)
boil	−188 °C (−306 °F)
density (1 atmosphere, 0 °C or 32 °F)	1.696 g/litre (0.226 ounce/gallon)
oxidation states	−1
negatron config.	1s 22s 22p 5

Story

The fluorine-containing inorganic fluorspar (or fluorite) was delineated in 1529 by the German MD and mineralogist Georgius Agricola. It appears likely that crude hydrofluoric acid was first prepared by an unknown English glassworker in 1720. In 1771 the Swedish chemist Carl Wilhelm Scheele obtained hydrofluoric acerb in an impure Department of State past heating fluorspar with concentrated oil of vitriol in a glass retort, which was greatly corroded by the product; as a result, vessels made of metallic were used in succeeding experiments with the substance. The nearly anhydrous venomous was prepared in 1809, and deuce years later the European country physicist André-Marie Ampère suggested that it was a compound of H with an unknown region element, similar to chlorine, for which he suggested the name fluorine. Fluorspar was then accepted to be calcium fluoride.

Britannica Test

118 Names and Symbols of the Periodic Table Quiz

The periodic table is ready-made up of 118 elements. How symptomless do you know their symbols? In this quiz you'll be shown all 118 chemical symbols, and you'll need to choose the name of the chemical ingredient that each one represents.

The isolation of fluorine was for a long time one of the chief unsolved problems in inorganic chemistry, and information technology was not until 1886 that the French chemist Henri Moissan prepared the element by electrolyzing a answer of potassium atomic number 1 fluoride in hydrogen fluoride. He conventional the 1906 Nobel Prize for Chemistry for uninflected fluorine. The difficulty in handling the element and its hepatotoxic properties contributed to the slow forward motion in fluorine chemistry. Indeed, up to the time of World State of war II the element appeared to equal a laboratory curiosity. Then, however, the function of uranium hexafluoride in the separation of uranium isotopes, along with the development of organic fluorine compounds of industrial grandness, made fluorine an progressive chemical of hefty use.

Occurrence and dispersion

The fluorine-containing material fluorite (fluo, CaF₂) has been exploited for centuries as a flux (cleansing agent) in assorted metallurgical processes. The name fluorspar is derivable from the Latin fluere, "to flow." The mineral later on proved to embody a source of the element, which was consequently named fluorine. The colourless, transparent crystals of fluorspar exhibit a bluish color when illuminated, and this material possession is accordingly known American Samoa fluorescence.

Fluorine is ground in nature alone in the form of its chemical compounds, except for trace amounts of the self-governing element in fluorspar that has been subjected to radiation from atomic number 88. Non a rare ingredient, it makes up about 0.065 percent of Worldly concern's crust. The principal sum fluorine-containing minerals are (1) fluorspar, deposits of which occur in Illinois, Kentucky, Derbyshire, southern Deutschland, the south of France, and Soviet Union and the chief source of fluorine, (2) Greenland spar (Na₃AlF₆), in the main from Greenland, (3) fluoroapatite (Ca₅[United States Post Office₄]₃[F,Cl]), cosmopolitan and containing protean amounts of atomic number and chlorine, (4) topaz (Al₂SiO₄[F,OH]₂), the gemstone, and (5) lepidolite, a mica also as a element of animal bones and teeth.

Physical and chemical properties

At room temperature fluorine is a faintly icteric gas with an irritating odour. Breathing in of the gas is dangerous. Upon cooling fluorine becomes a white-livered liquid. There is lone matchless stable isotope of the element, fluorine-19.

Because fluorine is the most electronegative of the elements, atomic groupings sumptuous in fluorine are often negatively charged. Methyl iodide (CH₃I) and trifluoroiodomethane (Cf₃I) have different charge distributions as shown in the following formulas, in which the Hellene symbol δ indicates a uncomplete charge:

The first ionisation energy of fluorine is real high (402 kilocalories per mole), giving a standard heat formation for the F⁺ cation of 420 kilocalories per bulwark.

The small size of the fluorine atom makes it likely to jam a comparatively large number of fluorine atoms surgery ions around a given coordination centre (central atom) where IT forms many stalls complexes—for example, hexafluorosilicate (SiF₆)²⁻ and hexafluoroaluminate (AlF₆)³⁻. Fluorine is the most powerfully oxidizing element. No other substance, therefore, is able to oxidize the fluoride anion to the free chemical element, and for this argue the element is not found in the free say in nature. For more than 150 years, all chemical methods had failed to bring out the element, success having been achieved only away the use of electrolytic methods. However, in 1986 American chemist Karl O. Christe reported the best chemical cooking of fluorine, where "chemical preparation" means a method that does not usage techniques such as electrolysis, photolysis, and dismissal or use F itself in the synthesis of any of the starting materials. Helium used K₂MnF₆ and antimony pentafluoride (SbF₅), some of which can be easily prepared from HF solutions.

The high oxidizing power of fluorine allows the element to produce the highest oxidation numbers possible in else elements, and many another high-stepped oxidation number fluorides of elements are far-famed for which there are no other corresponding halides—e.g., silver difluoride (AgF₂), cobalt trifluoride (CoF₃), rhenium heptafluoride (ReF₇), bromine pentafluoride (BrF₅), and iodine heptafluoride (IF₇).

Atomic number (F₂), composed of two fluorine atoms, combines with whol other elements omit He and neon to form ionic or covalent fluorides. Some metals, such A nickel, are rapidly covered by a fluoride layer, which prevents foster attack of the metal away the element. Certain dry metals, such as mild-mannered steel, copper, Al, or Monel (a 66 percent atomic number 28, 31.5 percentage Cu alloy), are non attacked by fluorine at ordinary temperatures. For work with fluorine at temperatures up to 600 °C (1,100 °F), Monel is suitable; sintered alumina is resistant up to 700 °C (1,300 °F). When lubricants are required, fluorocarbon oils are most suitable. Fluorine reacts violently with constitutional matter (such as rubber eraser, wood, and cloth), and controlled fluorination of organic compounds by the action of elemental fluorine is exclusive possible if uncommon precautions are taken.

why does scandium fluoride have a high melting point

Source: https://www.britannica.com/science/fluorine

Berbagi :