Рутений химические свойства, назначение, производство
Химические свойства
Ruthenium, a transition element, belongs to group VIII
(iron) of the periodic classification and to the light platinum
metals triad. It is a hard and brittle metal that resembles
platinum. It crystallizes in hexagonal form and occurs in the
form of seven stable isotopes: 96 (5.46%), 98 (1.87%), 99
(12.63%), 100 (12.53%), 101 (17.02%), 102 (31.6%), and
104 (18.87%). There are also several radioactive isotopes—93, 94, 95, 97, 103, 105, 106, 107, and 108—of which the
106 isotope characterized by strong β radiation and has a
half-life of 368 days; since it is produced in large quantities
in the nuclear reactors, it deserves special attention. Ruthenium
is the rarest of the platinum group elements (abundance
in the Earth’s crust ～0.0004 ppm). In chemical
compounds, it occurs at oxidation states from +2 to +8;
the most frequent is +3 in ruthenium compounds. Rutheniumis
resistant to acids and aqua regia, it is not oxidized in
the air at room temperature, and in the form of powder it
reacts with oxygen at elevated temperatures. It is dissolved
in molten strong alkalis and reacts with alkaline metal
peroxides and perchlorides. Ruthenium powder reacts
with chlorine above 200°C and with bromine at 300–
700°C.
Ruthenium compounds are usually dark brown (ranging
from yellow to black). Ruthenium forms alloys with platinum,
palladium, cobalt, nickel, and tungsten.
Физические свойства
Ruthenium is a rare, hard, silvery-white metallic element located in group 8, just aboveosmium and below iron, with which it shares some chemical and physical properties.Both ruthenium and osmium are heavier and harder than pure iron, making them morebrittle and difficult to refine. Both ruthenium and osmium are less tractable and malleable than iron. Although there are some similar characteristics between ruthenium and iron,ruthenium’s properties are more like those of osmium. Even so, ruthenium is less stablethan osmium. They are both rare and difficult to separate from minerals and ores that containother elements. These factors make it more difficult to determine ruthenium’s accurateatomic weight.
The oxidation state of +8 for ruthenium and its “mate” osmium is the highest oxidationstate of all elements in the transition series. Ruthenium’s melting point is 2,310°C, its boilingpoint is 3,900°C, and its density is 12.45 g/cm3.
Изотопы
There are 37 isotopes for ruthenium, ranging in atomic mass numbers from87 to 120. Seven of these are stable isotopes. The atomic masses and percentage ofcontribution to the natural occurrence of the element on Earth are as follows: Ru-96 =5.54%, Ru-98 = 1.87%, Ru-99 = 12.76%, Ru-100 = 12.60%, Ru-101 = 17.06%, Ru-102 = 31.55%, and Ru-104 = 18.62%.
Происхождение имени
“Ruthenium” is derived from the Latin word Ruthenia meaning “Russia,”
where it is found in the Ural Mountains.
Вхождение
Ruthenium is a rare element that makes up about 0.01 ppm in the Earth’s crust. Even so, itis considered the 74th most abundant element found on Earth. It is usually found in amountsup to 2% in platinum ores and is recovered when the ore is refined. It is difficult to separatefrom the leftover residue of refined platinum ore.
Ruthenium is found in South America and the Ural Mountains of Russia. There are someminor platinum and ruthenium ores found in the western United States and Canada. All ofthe radioactive isotopes of ruthenium are produced in nuclear reactors.
Характеристики
Ruthenium also belongs to the platinum group, which includes six elements with similarchemical characteristics. They are located in the middle of the second and third series of thetransition elements. The platinum group consists of ruthenium, rhodium,palladium, osmium, iridium, and platinum.
Ruthenium is a hard brittle metal that resists corrosion from all acids but is vulnerable tostrong alkalis (bases). Small amounts, when alloyed with other metals, will prevent corrosionof that metal.
Использование
Since ruthenium is rare and difficult to isolate in pure form, there are few uses for it. Itsmain uses are as an alloy to produce noncorrosive steel and as an additive to jewelry metalssuch as platinum, palladium, and gold, making them more durable.
It is also used as an alloy to make electrical contacts harder and wear longer, for medicalinstruments, and more recently, as an experimental metal for direct conversion of solar cellmaterial to electrical energy.
Ruthenium is used as a catalyst to affect the speed of chemical reactions, but is not alteredby the chemical process. It is also used as a drug to treat eye diseases.
Методы производства
Elemental ruthenium occurs in native alloys of iridium and
osmium (irridosmine, siskerite) and in sulfide and other ores
(pentlandite, laurite, etc.) in very small quantities that are
commercially recovered.
The element is separated from the other platinum metals
by a sequence involving treatment with aqua regia (separation
of insoluble osmium, rhodium, ruthenium, and iridium),
fusion with sodium bisulfate (with which rhodium reacts),
and fusion with sodium peroxide (dissolution of osmium and
ruthenium). The resulting solution of ruthenate and osmate is
treated with ethanol to precipitate ruthenium dioxide. The
ruthenium dioxide is purified by treatment with hydrochloric
acid and chlorine and reduced with hydrogen gas to pure
metal.
Ruthenium is recovered from exhausted catalytic converters
or, in a similar manner, from the waste produced during
platinum and nickel ore processing.
Определение
A transition
metal that occurs naturally with platinum.
It forms alloys with platinum that
are used in electrical contacts. Ruthenium
is also used in jewelry alloyed with palladium.Symbol: Ru; m.p. 2310°C; b.p.
3900°C; r.d. 12.37 (20°C); p.n. 44; r.a.m.
101.07.
Общее описание
This product has been enhanced for energy efficiency.
Опасность
The main hazard is the explosiveness of ruthenium fine power or dust. The metal willrapidly oxidize (explode) when exposed to oxidizer-type chemicals such as potassium chlorideat room temperature. Most of its few compounds are toxic and their fumes should beavoided.
Фармацевтические приложения
Ruthenium is the chemical element with the symbol Ru and atomic number 44. It occurs as a minor side
product in the mining of platinum. Ruthenium is relatively inert to most chemicals. Its main applications are
in the area of specialised electrical parts.
The success of cisplatin, together with the occurrence of dose-limiting resistances and severe side effects
such as nausea and nephrotoxicity, encouraged the research into other metal-based anticancer agents. Ruthenium
is one of those metals under intense research, and first results look very promising, with two candidates
– NAMI-A and KP1019 – having entered clinical trials.
Профиль безопасности
Most ruthenium compounds are poisons. Ruthenium is retained in the bones for a long time. Flammable in the form of dust when exposed to heat or flame. Violent reaction with ruthenium oxide. Explosive reaction with aqua rega + potassium chlorate. When heated to decomposition it emits very toxic fumes of RuO, and Ru, which are hghly injurious to the eyes and lung and can
produce nasal ulcerations. See also RUTHENIUM COMPOUNDS.
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