Иттрий

Химические свойства

Yttrium is a silvery-white to dark-gray, or black solid or gray powder. Odorless. An element in Group III-B of the Periodic Table. It is very similar to the rare earth metals.

Физические свойства

Yttrium is always found with the rare-earth elements, and in some ways it resembles them.Although it is sometimes classified as a rare-earth element, it is listed in the periodic table asthe first element in the second row (period 5) of the transition metals. It is thus also classifiedas the lightest in atomic weight of all the rare-earths. (Note: Yttrium is located in the periodictable just above the element lanthanum (group 3), which begins the lanthanide rare-earthseries.Yttrium dissolves in weak acids and also dissolves in strong alkalis such as potassiumhydroxide. It will also decompose in water.Yttrium’s melting point is 1,522°C, its boiling point is 5,338°C, and its density is 4.469g/cm³.

Изотопы

There are 50 isotopes of Yttrium. Only one is stable (Y-89), and it constitutes100% of the element’s natural existence on Earth. The other isotopes range from Y-77to Y-108 and are all produced artificially in nuclear reactions. The radioactive isotopeshave half-lives ranging from 105 nanoseconds to 106.65 days.

Происхождение имени

Yttrium was originally found with other elements in a mineral called gadolinite that was discovered in a mine near the Swedish the town of Ytterby.

Вхождение

Yttrium is the 27th most abundant element found on Earth, so it is not exactly correct tothink of it as “rare”—rather just difficult to find and extract from all the other similar elementsfound in its minerals.The mineral gadolinite that was discovered in a quarry near Ytterby, Sweden, was analyzedas (Ce,La,Nd,Y)2FeBe₂Si₂O₁₀. Today most yttrium is recovered from the ores of the mineralmonazite, which is a dark, sandy mixture of elements [(Ce,La,Th,Nd,Y)PO₄] and containsabout 50% rare-earths, including about 3% yttrium. The yttrium is separated from the otherrare-earths first by magnetic and flotation processes, which are followed by an iron-exchangedisplacement process. Yttrium’s ions are combined with fluorine ions that are then reduced byusing calcium metal that yields yttrium metal (3Ca + 2YF₃ → 2Y + 3CaF₂). This reductionprocess produces high-purity yttrium that can be formed into ingots, crystals, sponge, powder,and wires.

Характеристики

Yttrium (₃₉Y) is often confused with another element of the lanthanide series of rareEarths—Ytterbium (₇₀Yb). Also confusing is the fact that the rare-earth elements terbiumand erbium were found in the same minerals in the same quarry in Sweden. Yttrium rankssecond in abundance of all 16 rare-earth, and Ytterbium ranks 10th. Yttrium is a dark silverygray lightweight metal that, in the form of powder or shavings, will ignite spontaneously.Therefore, it is considered a moderately active rare-earth metal.

Использование

Although yttrium metal by itself is not very useful, it has many unusual applicationswhen combined as an alloy or as a compound with other elements. For example, whencombined with iron, it is known as garnet (Y₃Fe₅O₁₂), which is used as a “filter” in microwave communication systems. When garnets are made with aluminum instead of iron,they form semiprecious garnet gemstones (Y₃Al₅O₁₂) that resemble diamonds. Aluminumgarnets are referred to as “YAG” solid-state lasers because they are capable of intensifyingand strengthening a single frequency of light energy that is focused through a crystal ofgarnet. This produces a very powerful narrow band of light waves of a single color (microwave frequency). YAG-type lasers have found uses in the medical industry and as a cuttingtool for metals.When combined with oxygen and europium, yttrium produces the red phosphor used asa coating in color television screens to produce the bright red color. Yttrium is also used asan alloy metal and as a high-temperature coating on iron and steel alloys. It is used as a substance to deoxidize (remove the oxygen) during the production of nonferrous metals such asvanadium. Yttrium has the ability to “capture” neutrons, making it useful in the nuclear powerindustry. It is also used in the production of several types of semiconductors.

Определение

A silvery metallic element belonging to the second transition series. It is found in almost every lanthanoid mineral, particularly monazite. Yttrium is used in various alloys, in yttrium–aluminum garnets used in the electronics industry and as gemstones, as a catalyst, and in superconductors. A mixture of yttrium and europium oxides is widely used as the red phosphor on television screens. Symbol: Y; m.p. 1522°C; b.p. 3338°C; r.d. 4.469 (20°C); p.n. 39; r.a.m. 88.90585.

Общее описание

Soft silvery-white metal in bulk. Dark-gray to black odorless powder. Mp: 1509°C; bp 2927°C. Density: 4.47 g cm-3 at 20°C. May irritate the respiratory tract if inhaled as a powder. May irritate the digestive tract if swallowed. Vapors may cause dizziness or suffocation.

Профиль реактивности

YTTRIUM in bulk is stable in air due to the formation of oxide films. Powder or dust is light-sensitive and air-sensitive and flammable in the air and (Hazardous Chemicals Desk Reference, p. 861(1987)). Reacts with water to form gaseous hydrogen (H2). Reacts with strong oxidizing agents, strong acids, strong bases, and halogens. The products of these reactions are irritating and toxic.

Опасность

As a powder or in fine particles, yttrium is flammable and may spontaneously ignite inmoist air. Some of its compounds, particularly those used in the semiconductor and electricalindustries, are very toxic if inhaled or ingested and should only be used under proper conditions.

Угроза здоровью

Yttrium compounds cause pulmonary irritation in animals. No effects in humans have been reported.

Профиль безопасности

It may have an anticoagulant effect on the blood. Flammable in the form of dust when reacted with air, halogens.

Возможный контакт

Yttrium is used in iron and other alloys, in incandescent gas mantles, and as a deoxidizer for metals. Yttrium metal has a low cross section for neutron capture and is very stable at high temperatures. Further, it is very inert toward liquid uranium and many liquid uranium alloys. Thus, it may well have applications in nuclear power generation. The metal is usually prepared by reduction of the halide with an active metal, such as calcium. To identify and analyze this element, X-ray fluorescence spectroscopy is commonly employed.

Перевозки

UN3089 Metal powders, flammable, n.o.s., Hazard Class: 4.1; Labels: 4.1-Flammable solid. UN3178 Flammable solids, inorganic, n.o.s., Hazard Class: 4.1; Labels: 4.1-Flammable solid.

Несовместимости

Flammable in the form of dust; may form explosive mixture with air. A strong reducing agent; reacts violently with oxidizers (chlorates, nitrates, peroxides, permanganates, perchlorates, chlorine, bromine, fluorine, etc.); contact may cause fires or explosions. Keep away from alkaline materials, strong bases, strong acids, oxoacids, epoxides, halogens. Yttrium nitrate is a combustible material.

Утилизация отходов

Recovery is indicated wherever possible. Specifically, processes are available for yttrium oxysulfide recovery from color television tube manufacture.