ГАФНИЙ

Введение

атомный номер: 72
группа: 4 or IV B
Атомный вес: 178.49
период: 6
Количество CAS: 7440-58-6

классификация

халькогеном
галоген
Благородный газ
лантаноидное
актиноидов
Редкоземельный элемент
Металлов платиновой группы
трансурановый элемент
Нет стабильных изотопов
твердое тело
жидкость
газ
твердое тело (предсказанный)

Описание • Использование / функции

Hafnium was thought to be present in various minerals and concentrations many years prior to its discovery, in 1923, credited to D. Coster and G.von Hevesey. On the basis of the Bohr theory, the new element was expected to be associated with zirconium. It was finally identified in zircon fromNorway, by means of X-ray spectroscopic analysis. It was named in honor of the city in which the discovery was made. Most zirconium minerals contain1 to 5% hafnium. It was originally separated from zirconium by repeated recrystallization of the double ammonium or potassium fluorides by vonHevesey and Jantzen. Metallic hafnium was first prepared by van Arkel and deBoer by passing the vapor of the tetraiodide over a heated tungstenfilament. Almost all hafnium metal now produced is made by reducing the tetrachloride with magnesium or with sodium (Kroll Process). Hafniumis a ductile metal with a brilliant silver luster. Its properties are considerably influenced by the impurities of zirconium present. Of all the elements,zirconium and hafnium are two of the most difficult to separate. Their chemistry is almost identical, however, the density of zirconium is about halfthat of hafnium. Very pure hafnium has been produced, with zirconium being the major impurity. Natural hafnium contains six isotopes, one of whichis slightly radioactive. Hafnium has a total of 40 recognized isotopes and isomers. Because hafnium has a good absorption cross section for thermalneutrons (almost 600 times that of zirconium), has excellent mechanical properties, and is extremely corrosion resistant, it is used for reactor controlrods. Such rods are used in nuclear submarines. Hafnium has been successfully alloyed with iron, titanium, niobium, tantalum, and other metals.Hafnium carbide is the most refractory binary composition known, and the nitride is the most refractory of all known metal nitrides (m.p. 3310°C).Hafnium is used in gas-filled and incandescent lamps, and is an efficient “getter” for scavenging oxygen and nitrogen. Finely divided hafnium ispyrophoric and can ignite spontaneously in air. Care should be taken when machining the metal or when handling hot sponge hafnium. At 700°Chafnium rapidly absorbs hydrogen to form the composition HfH1.86. Hafnium is resistant to concentrated alkalis, but at elevated temperatures reactswith oxygen, nitrogen, carbon, boron, sulfur, and silicon. Halogens react directly to form tetrahalides. The price of the metal is in the broad range of$1/g to $3/g, depending on purity and quantity. The yearly demand for hafnium in the U.S. is now in excess of 50,000 kg. 1

• "A number of transition metals (Ti, Zr, Hf, V, Nb, Ta, Mo, W) form interstitial carbides of composition MC and, in some cases, M2C. These carbides have extremely high melting points; they are very hard, and they are good electrical conductors." 2

Физические свойства

Температура плавления:3*  2233 °C = 2506.15 K = 4051.4 °F
Точка кипения:3* 4603 °C = 4876.15 K = 8317.4 °F
возгонки:3 
тройная точка:3 
Критическая точка:3 
плотность:4  13.3 g/cm3

* - at 1 atm

Электронная конфигурация

Электронная конфигурация: [Xe] 6s2 4f14 5d2
блок: d
Самый высокий уровень энергии Занято: 6
валентных электронов: 

Квантовые числа:

n = 5
ℓ = 2
m = -1
ms = +½

Связующие

Электроотрицательность (Полинг шкала):5 1.3
Electropositivity (Полинг шкала): 2.7
сродства к электрону:6 abt 0 eV
Окисление Штаты: +4

ионизационный потенциал   eV 7  kJ/mol  
1 6.82507    658.5
ионизационный потенциал   eV 7  kJ/mol  
2 14.9    1437.6
ионизационный потенциал   eV 7  kJ/mol  
3 23.3    2248.1
4 33.33    3215.9

термохимия

Удельная теплоемкость: 0.144 J/g°C 8 = 25.703 J/mol°C = 0.034 cal/g°C = 6.143 cal/mol°C
Теплопроводность: 23 (W/m)/K, 27°C 9
Теплота плавления: 24.06 kJ/mol 10 = 134.8 J/g
Теплота парообразования: 575 kJ/mol 11 = 3221.5 J/g
Состояние материи Энтальпия образования (ΔHf°)12 Энтропия (S°)12 Свободная энергия Гиббса (ΔGf°)12
(kcal/mol) (kJ/mol) (cal/K) (J/K) (kcal/mol) (kJ/mol)
(s hexagonal) 0 0 10.41 43.55544 0 0
(g) 148.0 619.232 44.642 186.782128 137.8 576.5552

Изотопы

нуклид масса 13 Период полураспада 13 Ядерный Спин 13 энергия связи
153Hf 152.97069(54)# 400# ms [>200 ns] 1/2+# 1,206.53 MeV
154Hf 153.96486(54)# 2(1) s 0+ 1,223.91 MeV
155Hf 154.96339(43)# 890(120) ms 7/2-# 1,231.98 MeV
156Hf 155.95936(22) 23(1) ms 0+ 1,249.37 MeV
157Hf 156.95840(21)# 115(1) ms 7/2- 1,257.44 MeV
158Hf 157.954799(19) 2.84(7) s 0+ 1,265.51 MeV
159Hf 158.953995(18) 5.20(10) s 7/2-# 1,273.58 MeV
160Hf 159.950684(12) 13.6(2) s 0+ 1,281.65 MeV
161Hf 160.950275(24) 18.2(5) s 3/2-# 1,289.73 MeV
162Hf 161.94721(1) 39.4(9) s 0+ 1,307.11 MeV
163Hf 162.94709(3) 40.0(6) s 3/2-# 1,315.18 MeV
164Hf 163.944367(22) 111(8) s 0+ 1,323.25 MeV
165Hf 164.94457(3) 76(4) s (5/2-) 1,331.33 MeV
166Hf 165.94218(3) 6.77(30) min 0+ 1,339.40 MeV
167Hf 166.94260(3) 2.05(5) min (5/2)- 1,347.47 MeV
168Hf 167.94057(3) 25.95(20) min 0+ 1,355.54 MeV
169Hf 168.94126(3) 3.24(4) min (5/2)- 1,363.61 MeV
170Hf 169.93961(3) 16.01(13) h 0+ 1,381.00 MeV
171Hf 170.94049(3) 12.1(4) h 7/2(+) 1,379.75 MeV
172Hf 171.939448(26) 1.87(3) a 0+ 1,397.14 MeV
173Hf 172.94051(3) 23.6(1) h 1/2- 1,395.90 MeV
174Hf 173.940046(3) 2.0(4)E+15 a 0+ 1,403.97 MeV
175Hf 174.941509(3) 70(2) d 5/2- 1,412.04 MeV
176Hf 175.9414086(24) СТАБИЛЬНЫЙ 0+ 1,420.11 MeV
177Hf 176.9432207(23) СТАБИЛЬНЫЙ 7/2- 1,428.18 MeV
178Hf 177.9436988(23) СТАБИЛЬНЫЙ 0+ 1,436.25 MeV
179Hf 178.9458161(23) СТАБИЛЬНЫЙ 9/2+ 1,444.32 MeV
180Hf 179.9465500(23) СТАБИЛЬНЫЙ 0+ 1,452.40 MeV
181Hf 180.9491012(23) 42.39(6) d 1/2- 1,460.47 MeV
182Hf 181.950554(7) 8.90(9)E+6 a 0+ 1,459.22 MeV
183Hf 182.95353(3) 1.067(17) h (3/2-) 1,467.29 MeV
184Hf 183.95545(4) 4.12(5) h 0+ 1,475.37 MeV
185Hf 184.95882(21)# 3.5(6) min 3/2-# 1,483.44 MeV
186Hf 185.96089(32)# 2.6(12) min 0+ 1,482.19 MeV
187Hf 186.96459(43)# 30# s [>300 ns] 1,490.27 MeV
188Hf 187.96685(54)# 20# s [>300 ns] 0+ 1,498.34 MeV
Значения, отмеченные # не чисто получены из экспериментальных данных, но, по крайней мере, частично от систематических тенденций. Спины с аргументами слабые присваивания заключены в круглые скобки. 13

Реакции

изобилие

Земля - Исходные соединения: oxides 22
Земля - морская вода: 0.000007 mg/L 23
Земля -  корка:  3 mg/kg = 0.0003% 23
Земля -  Всего:  230 ppb 24
Планета Меркурий) -  Всего:  177 ppb 24
Венера -  Всего:  241 ppb 24
Хондриты - Всего: 0.17 (relative to 106 atoms of Si) 25

соединений

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Внешние ссылки:

источники

(1) - Lide, David R. CRC Handbook of Chemistry and Physics, 83rd ed.; CRC Press: Boca Raton, FL, 2002; p 4:14.
(2) - Jolly, William L. The Chemistry of the Non-Metals; Prentice-Hall: Englewood Cliffs, New Jersey, 1966; p 119.
(3) - Lide, David R. CRC Handbook of Chemistry and Physics, 83rd ed.; CRC Press: Boca Raton, FL, 2002; p 4:132.
(4) - Lide, David R. CRC Handbook of Chemistry and Physics, 84th ed.; CRC Press: Boca Raton, FL, 2002; p 4:39-4:96.
(5) - Dean, John A. Lange's Handbook of Chemistry, 11th ed.; McGraw-Hill Book Company: New York, NY, 1973; p 4:8-4:149.
(6) - Lide, David R. CRC Handbook of Chemistry and Physics, 84th ed.; CRC Press: Boca Raton, FL, 2002; p 10:147-10:148.
(7) - Lide, David R. CRC Handbook of Chemistry and Physics, 83rd ed.; CRC Press: Boca Raton, FL, 2002; p 10:178 - 10:180.
(8) - Lide, David R. CRC Handbook of Chemistry and Physics, 83rd ed.; CRC Press: Boca Raton, FL, 2002; p 4:133.
(9) - Lide, David R. CRC Handbook of Chemistry and Physics, 83rd ed.; CRC Press: Boca Raton, FL, 2002; pp 6:193, 12:219-220.
(10) - Lide, David R. CRC Handbook of Chemistry and Physics, 83rd ed.; CRC Press: Boca Raton, FL, 2002; pp 6:123-6:137.
(11) - Lide, David R. CRC Handbook of Chemistry and Physics, 83rd ed.; CRC Press: Boca Raton, FL, 2002; pp 6:107-6:122.
(12) - Dean, John A. Lange's Handbook of Chemistry, 12th ed.; McGraw-Hill Book Company: New York, NY, 1979; p 9:4-9:94.
(13) - Atomic Mass Data Center. http://amdc.in2p3.fr/web/nubase_en.html (accessed July 14, 2009).
(14) - Kotz, John C., Treichel, Paul, and Weaver, Gabriela. Chemistry & Chemical Reactivity 6th ed.; Thomson Brooks/Cole: Belmont, CA, 2006; p 166.
(15) - Ebbing, Darrell D. General Chemistry 3rd ed.; Houghton Mifflin Company: Boston, MA, 1990; p 139.
(16) - Silberberg, Martin S. Chemistry: The Molecular Nature of Matter and Change 4th ed.; McGraw-Hill: Boston, MA, 2006; p 127.
(17) - Zumdahl, Steven and Zumdahl, Susan A. Chemistry 9th ed.; Brooks/Cole: Belmont, CA, 2014; p 132.
(18) - Zumdahl, Steven and Zumdahl, Susan A. Chemistry 9th ed.; Brooks/Cole: Belmont, CA, 2014; p 131.
(19) - Kotz, John C., Treichel, Paul, and Weaver, Gabriela. Chemistry & Chemical Reactivity 6th ed.; Thomson Brooks/Cole: Belmont, CA, 2006; p 166.
(20) - Halka, Monica and Nordstrom, Brian. Metals & Metalloids; Infobase Publishing: New York, NY, 2011; pg. 86.
(21) - Swaddle, T.W. Inorganic Chemistry; Academic Press: San Diego, 1997; p 230.
(22) - Silberberg, Martin S. Chemistry: The Molecular Nature of Matter and Change, 4th ed.; McGraw-Hill Higher Education: Boston, MA, 2006, p 965.
(23) - Lide, David R. CRC Handbook of Chemistry and Physics, 83rd ed.; CRC Press: Boca Raton, FL, 2002; p 14:17.
(24) - Morgan, John W. and Anders, Edward, Proc. Natl. Acad. Sci. USA 77, 6973-6977 (1980)
(25) - Brownlow, Arthur. Geochemistry; Prentice-Hall, Inc.: Englewood Cliffs, NJ, 1979, pp 15-16.