vanadium

V. Atomic number 23. A transition metal element in group 5 of the periodic table with the electron configuration [Ar]3d ³ 4s ^2. Formerly known as vanadium. In 1830, Sweden's N.G. Sefström and J. Berzelius discovered vanadium by analyzing iron ore produced in the country, and named it after Freyja Vanadis, the Norse goddess of love and beauty. However, it was discovered that vanadium had in fact been discovered by A. Manuel del Rio of Mexico in 1801. Atomic weight 50.9415(1). It is the only stable isotope found in nature. It exists as a metal with mass numbers of 51 (99.750(4)%) and 50 (0.250(4)%) (half-life 1.4×10 ¹⁷ y, β ^- , EC). In addition, there are radioactive isotopes with mass numbers of 40 to 65.
Vanadium is abundant in the earth's crust at 230 ppm, and is distributed widely in sedimentary rocks, but rarely occurs as a single deposit. The main minerals are patronite (a complex sulfide), vanadinite (Pb ₅ (VO ₄ ) ₃ Cl), and carnotite (K(UO ₂ )VO ₄ (3/2)H ₂ O). Resources used include titanomagnetite, carnotite (uranium ore), phosphate ore, lead-zinc ore, and minor components of crude oil. V 2 O 5 is obtained from titanomagnetite itself, or from slags used in obtaining the main product, heavy oil boiler ash, or used desulfurization catalysts for oil refining. The metal is obtained by reducing _{V 2 O 5 with Al (} thermit process) or by reducing chlorides with calcium. Ultra-high purity (> 99.95%) vanadium can be obtained by thermal decomposition of iodide _VI2 (van Arkel-deBoer process) or molten salt electrolysis of chloride _VCl2 . Russia and China each hold 38% of the world's minable reserves, followed by South Africa (23%), and it is mainly titanomagnetite. Japan imports almost all of its reserves from South Africa (49%), China (25%), Russia (8%), etc. (2005). Ultra-high purity vanadium is a hard, steel-colored metal that is resistant to corrosion. Density 6.11 g cm ^-3 (19 °C). Melting point 1887 °C, boiling point 3377 °C. Superconducting below 5.40 K. Usual oxidation states 2 to 5. Insoluble in water, hydrochloric acid, and alkaline aqueous solutions, soluble in nitric acid, hot concentrated sulfuric acid, aqua regia, hydrofluoric acid, and perchloric acid. At high temperatures, it reacts with most nonmetals, forming _VCl4 with chlorine and the interstitial compound VN with nitrogen. It also reacts with As, C, Si, B, etc., mostly forming interstitial, non-stoichiometric compounds. When heated in air, it changes in sequence from _gray ^VⅡO _{to black VⅢ2O3} ^, dark blue ^VⅣ2O4 , _and orange _- red, _and is oxidized to ^VⅤ2O5 .
When vanadium is added to steel, it exhibits excellent tensile strength, heat resistance, toughness, and abrasion resistance, and is therefore used in large quantities to manufacture high tensile steel, structural steel, and high speed steel. It is also widely used as an alloy material with titanium, aluminum, and zirconium. Ti-Al-V alloys are used in aircraft and spacecraft materials, and golf club materials. Approximately 90% of demand is in the steel industry, but it is also used as a catalyst and pigment. It is one of the important rare metals that is indispensable to industry, and is subject to the national stockpiling system. Vanadium and its compounds are classified as harmful air pollutants under the Air Pollution Control Act. [CAS 7440-62-2]

Source: Morikita Publishing "Chemical Dictionary (2nd Edition)" Information about the Chemical Dictionary 2nd Edition

V．原子番号23の元素．電子配置[Ar]3d³4s²の周期表5族遷移金属元素．旧元素名バナジン．1830年，スウェーデンのN.G.SefströmとJ. Berzelius(ベルセリウス)が同国産の鉄鉱石を分析して発見し，北欧神話の愛と美の女神Freyja Vanadisから命名したが，じつは1801年にメキシコのA.Manuel del Rioがすでに見いだしていたものであることがわかった．原子量50.9415(1)．天然には唯一の安定同位体．質量数51(99.750(4)％)と50(0.250(4)％)(半減期1.4×10¹⁷ y，β^－，EC)が存在する．このほか，40～65の放射性同位体がある．
バナジウムの地殻中の存在度は230 ppm で，堆積岩中にかなり広く分布しているが，単独の鉱床として存在することはまれである．主要鉱物はパトロン石(patronite，複雑な硫化物)，褐鉛鉱(vanadinite，Pb₅(VO₄)₃Cl)，カルノー石(carnotite，K(UO₂)VO₄(3/2)H₂O)などがある．資源として利用されるものは，チタン磁鉄鉱，カルノー石(ウラン鉱石)，リン鉱石，鉛・亜鉛鉱石，原油などの副成分で，チタン磁鉄鉱自身，または主要目的物を得る際の鉱さい，重油ボイラーの煙灰や使用済み石油精製用脱硫触媒を原料としてV₂O₅が得られる．金属はV₂O₅のAlによる還元(テルミット法)や，塩化物のカルシウムによる還元による．超高純度( ＞ 99.95％)のものは，ヨウ化物VI₂の熱分解(van Arkel-deBoer法)や，塩化物VCl₂の溶融塩電解で得られる．世界の可掘埋蔵量の38％ ずつがロシアと中国，ついで南アフリカ(23％)で，おもにチタン磁鉄鉱である．わが国は，ほぼ全量を南アフリカ(49％)，中国(25％)，ロシア(8％)などから輸入している(2005年)．超高純度のバナジウムは，腐食されにくい硬い鋼色の金属である．密度6.11 g cm^－3(19 ℃)．融点1887 ℃，沸点3377 ℃．5.40 K 以下で超伝導を示す．通常の酸化数2～5．水，塩酸，アルカリ水溶液に不溶，硝酸，熱濃硫酸，王水，フッ化水素酸，過塩素酸に可溶．高温ではたいていの非金属と反応し，塩素とはVCl₄，窒素とは侵入型化合物VNをつくる．As，C，Si，Bなどとも反応して，多くは侵入型，非化学量論的化合物をつくる．空気中で熱すると，灰色V^ⅡO，黒色V^Ⅲ₂O₃，暗青色V^Ⅳ₂O₄，橙赤色と順次変化し，V^Ⅴ₂O₅まで酸化される．
バナジウムを鉄鋼に添加するとすぐれた高抗張力性，耐熱性，靭性，耐摩耗性などを示すので，高抗張力鋼，構造用鋼，高速度鋼製造用に大量に使用される．チタン,アルミニウム，ジルコニウムとの合金材料としても広く用いられる．Ti-Al-V合金は航空機・宇宙用材料，ゴルフクラブ用材料．鉄鋼分野の需要が約90％ を占めるが，触媒，顔料用としても使われる．産業にとって欠くことのできない重要なレアメタルの一つで，国家備蓄制度の対象となっている．「バナジウム及びその化合物」は大気汚染防止法・有害大気汚染物質である．[CAS 7440-62-2]

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