المعرفة

أپاتيت

(تم التحويل من أباتيت)

أپاتيت Apatite هي مجموعة من معادن الفوسفات، عادةً تشير إلى هيدروكسيل‌أپاتيت، فلورأپاتيت و كلورأپاتيت، مع تركزات عالية من OH−, F− و Cl− أيونات، بالترتيب، في البلورة. صيغة مزيج الأربع endmembers الأكثر شيوعا تـُكتب Ca10(PO4)6(OH,F,Cl)2، وصيغ خلية الوحدة البلورية للمعادن المنفردة تـُكتب كالتالي Ca10(PO4)6(OH)2, Ca10(PO4)6F2 و Ca10(PO4)6Cl2.

مجموعة الأپاتيت
Apatite group
Apatite Canada.jpg
العامة
التصنيفمعادن الفوسفات
الصيغة
(repeating unit)		Ca5(PO4)3(F,Cl,OH)
تصنيف سترونز8.BN.05
النظام البلوريHexagonal
Crystal classDipyramidal (6/m)
(same H-M symbol)[1]
التعرف
ColorTransparent to translucent, usually green, less often colorless, yellow, blue to violet, pink, brown.[2]
Crystal habitTabular, prismatic crystals, massive, compact or granular
Cleavage[0001] indistinct, [1010] indistinct[1]
FractureConchoidal to uneven[2]
Mohs scale hardness5[2] (defining mineral)
LusterVitreous[2] to subresinous
StreakWhite
DiaphaneityTransparent to translucent[1]
الجاذبية النوعية3.16–3.22[1]
Polish lusterVitreous[2]
الصفات البصريةDouble refractive, uniaxial negative[2]
Refractive index1.634–1.638 (+0.012, −0.006)[2]
Birefringence0.002–0.008[2]
PleochroismBlue stones – strong, blue and yellow to colorless. Other colors are weak to very weak.[2]
التشتت0.013[2]
Ultraviolet fluorescenceYellow stones – purplish-pink, which is stronger in long wave; blue stones – blue to light-blue in both long and short wave; green stones – greenish-yellow, which is stronger in long wave; violet stones – greenish-yellow in long wave, light-purple in short wave.[2]

سـُمي المعدن أپاتيت من قِبل الجيولوجي الألماني ابراهام گوتلوب ڤرنر في 1786،[3] although the specific mineral he had described was reclassified as fluorapatite in 1860 by the German mineralogist Karl Friedrich August Rammelsberg. Apatite is often mistaken for other minerals. This tendency is reflected in the mineral's name, which is derived from the Greek word απατείν (apatein), which means to deceive or to be misleading.[4]

الأپاتيت هو أحد المعادن القليلة تـُنتجها وتستخدمها الأنظمة الحيوية البيئية الدقيقة. والأپاتيت هو المعدن المُعرِّف للقيمة 5 على مقياس موز. الهيدروكسي‌أپاتيت، المعروف أيضاً بإسم هيدروكسيل‌أپاتيت، هو المكون الرئيسي في مينا الأسنان و معدن العظم. وثمة شكل نادر نسبياً من الأباتيت تكون فيه معظم مجموعات OH غائبة وتحتوي على العديد الكربونات واستبدالات الفوسفات الحامضية هي مكون كبير في مادة عظم.

Fluorapatite (or fluoroapatite) is more resistant to acid attack than is hydroxyapatite; in the mid-20th century, it was discovered that communities whose water supply naturally contained fluorine had lower rates of dental caries.[5] Fluoridated water allows exchange in the teeth of fluoride ions for hydroxyl groups in apatite. Similarly, toothpaste typically contains a source of fluoride anions (e.g. sodium fluoride, sodium monofluorophosphate). Too much fluoride results in dental fluorosis and/or skeletal fluorosis.

Fission tracks in apatite are commonly used to determine the thermal history of orogenic (mountain) belts and of sediments in sedimentary basins. (U-Th)/He dating of apatite is also well established for use in determining thermal histories and other, less typical applications such as paleo-wildfire dating.

الفسفوريت هو صخر رسوبي غني بالفوسفات، يحتوي بين 18% و 40% P2O5. الأپاتيت في الفسفوريت يتواجد ككتل cryptocrystalline يشار إليها كـ collophane.

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الاستخدامات

 
أپاتيتي، روسيا، هو موقع مناجم ومنشآت إعداد الأپاتيت

الاستخدام الرئيسي للأپاتيت هي في صناعة الأسمدة – فهو مصدر للفسفور. وأحياناً يُستخدم كحجر كريم. التنويعات الخضراء والزرقاء، في شكل مقسم ناعم، هي خضابات بقوة تغطية ممتازة.

أثناء هضم الأپاتيت مع حمض الكبريتيك لانتاج حمض الفسفوريك، فإن فلوريد الهيدروجين ينتـُج كناتج جانبي من أي محتوى فلورأپاتيت. هذا الناتج الجانبي هو مصدر صناعي ثانوي بـحمض الهيدروفلوريك.[6]

Fluoro-chloro apatite forms the basis of the now obsolete Halophosphor fluorescent tube phosphor system. Dopant elements of manganese and antimony, at less than one mole-percent, in place of the calcium and phosphorus impart the fluorescence, and adjustment of the fluorine-to-chlorine ratio adjusts the shade of white produced. This system has been almost entirely replaced by the Tri-Phosphor system.[7]

في الولايات المتحدة، apatite-derived fertilizers are used to supplement the nutrition of many agricultural crops by providing a valuable source of الفوسفات.

Apatites are also a proposed host material for storage of nuclear waste, along with other phosphates.


علم المجوهرات

 
أپاتيت أزرق بواجهات، من البرازيل

Apatite is infrequently used as a gemstone. Transparent stones of clean color have been faceted, and chatoyant specimens have been cabochon-cut.[2] Chatoyant stones are known as cat's-eye apatite,[2] transparent green stones are known as asparagus stone,[2] and blue stones have been called moroxite.[8] If crystals of rutile have grown in the crystal of apatite, in the right light the cut stone displays a cat's-eye effect. Major sources for gem apatite are[2] Brazil, Burma, and Mexico. Other sources include[2] Canada, Czech Republic, Germany, India, Madagascar, Mozambique, Norway, South Africa, Spain, Sri Lanka, and the United States.

الاستخدام كمعدن خام

 
بلورة أپاتيت، المكسيك

أحياناً يحتوي الأپاتيت كميات معتبرة من العناصر الأرضية النادرة ويمكن استخدامه كخام لتلك الفلزات.[9] This is preferable to traditional rare-earth ores, as apatite is non-radioactive[10] and does not pose an environmental hazard in mine tailings. إلا أن بعض الأباتيت في فلوريدا المستخدم لانتاج الفوسفات للزراعة لا يحتوي يورانيوم أو راديوم أو رصاص-210 أو پولونيوم-210 أو رادون.[11][12]

أپاتيت هو معدن خام في مشروع بحيرة هويداس للمعادن الترابية النادرة.[13]

ثرموديناميكا

The standard enthalpies of formation in the crystalline state of hydroxyapatite, chlorapatite and a preliminary value for bromapatite, have been determined by reaction-solution calorimetry. Speculations on the existence of a possible fifth member of the calcium apatites family, iodoapatite, have been drawn from energetic considerations.[14]

 
An apatite mine near Kirovsk in the Khibiny Mountains, one of Russia's main sources of phosphate fertilizer

Structural and thermodynamic properties of crystal hexagonal calcium apatites, Ca10(PO4)6(X)2 (X= OH, F, Cl, Br), have been investigated using an all-atom Born-Huggins-Mayer potential[15] by a molecular dynamics technique. The accuracy of the model at room temperature and atmospheric pressure was checked against crystal structural data, with maximum deviations of c. 4% for the haloapatites and 8% for hydroxyapatite. High-pressure simulation runs, in the range 0.5-75 kbar, were performed in order to estimate the isothermal compressibility coefficient of those compounds. The deformation of the compressed solids is always elastically anisotropic, with BrAp exhibiting a markedly different behavior from those displayed by HOAp and ClAp. High-pressure p-V data were fitted to the Parsafar-Mason equation of state[16] with an accuracy better than 1%.[17]

The monoclinic solid phases Ca10(PO4)6(X)2 (X= OH, Cl) and the molten hydroxyapatite compound have also been studied by molecular dynamics.[18][19]

العـِلم القمري

صخور القمر collected by astronauts during the Apollo program contain traces of apatite.[20] Re-analysis of these samples in 2010 revealed water trapped in the mineral as hydroxyl, leading to estimates of water on the lunar surface at a rate of at least 64 parts per billion – 100 times greater than previous estimates – and as high as 5 parts per million.[21] If the minimum amount of mineral-locked water was hypothetically converted to liquid, it would cover the Moon's surface in roughly one meter of water.[22]

Bio-leaching

The ectomycorrhizal fungi Suillus granulatus and Paxillus involutus can release elements from apatite.[23]

انظر أيضاً

الهامش

  1. ^ أ ب ت ث Apatite. Webmineral
  2. ^ أ ب ت ث ج ح خ د ذ ر ز س ش ص ض ط Gemological Institute of America, GIA Gem Reference Guide 1995, ISBN 0-87311-019-6
  3. ^ According to Werner himself — (Werner, 1788), p. 85 — الاسم "أپاتيت" ظهر مطبوعاً لأول مرة في:
    • Gerhard, C.A., Grundriss des Mineral-systems [Outline of the system of minerals] (Berlin, (Germany): Christian Friedrich Himburg, 1786), p. 281. From p. 281: "Von einigen noch nicht genau bestimmten und ganz neu entdeckten Mineralien. Ich rechne hierzu folgende drei Körper: 1. Den Apatit des Herrn Werners. … "(On some still not precisely determined and quite recently discovered minerals. I count among these the following three substances: 1. the apatite of Mr. Werner. … )
    وصَف ڤرنر المعدن في بعض التفاصيل في مقال في 1788.
    • Werner, A.G. (1788) "Geschichte, Karakteristik, und kurze chemische Untersuchung des Apatits" (History, characteristics, and brief chemical investigation of apatite), Bergmännisches Journal (Miners' Journal), vol. 1, pp. 76–96. On pp. 84–85, Werner explained that because mineralogists had repeatedly misclassified it (e.g., as aquamarine), he gave apatite the name of "deceiver": "Ich wies hierauf diesem Foßile, als einer eigenen Gattung, sogleich eine Stelle in dem Kalkgeschlechte an; und ertheilte ihm, — weil es bisher alle Mineralogen in seiner Bestimmung irre geführt hatte, — den Namen Apatit, den ich von dem griechischen Worte απατάω (decipio) bildete, und welcher so viel as Trügling sagt." (I then immediately assigned to this fossil [i.e., material obtained from underground], as a separate type, a place in the lime lineage; and conferred on it — because it had previously led astray all mineralogists in its classification — the name "apatite", which I formed from the Greek word απατάω [apatao] (I deceive) and which says as much as [the word] "deceiver".)
  4. ^ "Fluorapatite mineral information and data". mindat.org. Retrieved 30 January 2018.
  5. ^ National Institute of Dental and Craniofacial Research. The story of fluoridation; 2008-12-20.
  6. ^ Villalba, Gara; Ayres, Robert U.; Schroder, Hans (2008). "Accounting for Fluorine: Production, Use, and Loss". Journal of Industrial Ecology. 11: 85–101. doi:10.1162/jiec.2007.1075.
  7. ^ Henderson and Marsden, "Lamps and Lighting", Edward Arnold Ltd., 1972, ISBN 0-7131-3267-1
  8. ^ Streeter, Edwin W., Precious Stones and Gems 6th edition, George Bell and Sons, London, 1898, p306
  9. ^ Salvi S, Williams‐Jones A. 2004. Alkaline granite‐syenite deposits. In Linnen RL, Samson IM, editors. Rare element geochemistry and mineral deposits. St. Catharines (ON): Geological Association of Canada. pp. 315‐341 ISBN 1-897095-08-2
  10. ^ Haxel G, Hedrick J, Orris J. 2006. Rare earth elements critical resources for high technology. Reston (VA): United States Geological Survey. USGS Fact Sheet: 087‐02.
  11. ^ Proctor, Robert N. (2006-12-01) Puffing on Polonium – New York Times. Nytimes.com. Retrieved on 2011-07-24.
  12. ^ Tobacco Smoke | Radiation Protection | US EPA. Epa.gov (2006-06-28). Retrieved on 2011-07-24.
  13. ^ Great Western Minerals Group Ltd. | Projects – Hoidas Lake, Saskatchewan. Gwmg.ca (2010-01-27). Retrieved on 2011-07-24.
  14. ^ Cruz, F.J.A.L.; Minas da Piedade, M.E.; Calado, J.C.G. (2005). "Standard molar enthalpies of formation of hydroxy-, chlor-, and bromapatite". J. Chem. Thermodyn. 37 (10): 1061–1070. doi:10.1016/j.jct.2005.01.010.
  15. ^ See: Born-Huggins-Mayer potential (SklogWiki)
  16. ^ Parsafar, Gholamabbas and Mason, E.A. (1994) "Universal equation of state for compressed solids," Physical Review B Condensed Matter, 49 (5)  : 3049–3060.
  17. ^ Cruz, F.J.A.L.; Canongia Lopes, J.N.; Calado, J.C.G.; Minas da Piedade, M.E. (2005). "A Molecular Dynamics Study of the Thermodynamic Properties of Calcium Apatites. 1. Hexagonal Phases". J. Phys. Chem. B. 109 (51): 24473–24479. doi:10.1021/jp054304p.
  18. ^ Cruz, F.J.A.L.; Canongia Lopes, J.N.; Calado, J.C.G. (2006). "Molecular Dynamics Study of the Thermodynamic Properties of Calcium Apatites. 2. Monoclinic Phases". J. Phys. Chem. B. 110 (9): 4387–4392. doi:10.1021/jp055808q.
  19. ^ Cruz, F.J.A.L.; Canongia Lopes, J.N.; Calado, J.C.G. (2006). "Molecular dynamics simulations of molten calcium hydroxyapatite". Fluid Phase Eq. 241 (1–2): 51–58. doi:10.1016/j.fluid.2005.12.021.
  20. ^ Smith, J. V.; Anderson, A. T.; Newton, R. C.; Olsen, E. J.; Crewe, A. V.; Isaacson, M. S. (1970). "Petrologic history of the moon inferred from petrography, mineralogy and petrogenesis of Apollo 11 rocks". Geochimica et Cosmochimica Acta. 34, Supplement 1: 897–925. Bibcode:1970GeCAS...1..897S. doi:10.1016/0016-7037(70)90170-5.
  21. ^ McCubbina, Francis M.; Steele, Andrew; Haurib, Erik H.; Nekvasilc, Hanna; Yamashitad, Shigeru; Russell J. Hemleya (2010). "Nominally hydrous magmatism on the Moon". Proceedings of the National Academy of Sciences. 107 (25): 11223–11228. Bibcode:2010PNAS..10711223M. doi:10.1073/pnas.1006677107. PMC 2895071. PMID 20547878.
  22. ^ Fazekas, Andrew "Moon Has a Hundred Times More Water Than Thought" National Geographic News (June 14, 2010). News.nationalgeographic.com (2010-06-14). Retrieved on 2011-07-24.
  23. ^ Geoffrey Michael Gadd (March 2010). "Metals, minerals and microbes: geomicrobiology and bioremediation". Microbiology. pp. 609–643.
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