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Both the 02, 1\u0304 and 13\u0304, 13 reflections show changes in the XRD patterns along the kaolinite to halloysite-7 \u00c5 transition, and the FTIR spectra show changes corresponding to both OH<jats:sup>\u2212<\/jats:sup> and Si-O-stretching bands and Al-O-Si-bending vibrations. The interlayer water content in the kaolinite structure increases during transition. The two-layer periodicity of well-ordered kaolinite and rolling up of kaolinite plates are observed using high-resolution transmission electron microscopy (HRTEM). Long and short tubes exhibit halloysite-7 \u00c5. No structural Fe was found in the kaolinite samples. Analytical electron microscopy (AEM) indicates no substitution of Al<jats:sup>3+<\/jats:sup> for Si<jats:sup>4+<\/jats:sup>. The Si\/Al ratio shows values of \u223c1 for the kaolinite and rolled kaolinite plates. The <jats:sup>27<\/jats:sup>Al magic angle spinning neutron magnetic resonance (MAS-NMR) spectra display a resonance centered at \u223c1 ppm, assigned to six-coordinated aluminum. The transformation of kaolinite to halloysite-7 \u00c5 is controlled by surface reaction.<\/jats:p>","DOI":"10.1346\/ccmn.2001.0490609","type":"journal-article","created":{"date-parts":[[2006,9,13]],"date-time":"2006-09-13T07:08:17Z","timestamp":1158131297000},"page":"596-607","source":"Crossref","is-referenced-by-count":67,"title":["Kaolinite to Halloysite-7 \u00c5 Transformation in the Kaolin Deposit of S\u00e3o Vicente De Pereira, Portugal"],"prefix":"10.1017","volume":"49","author":[{"given":"Iuliu","family":"Bobos","sequence":"first","affiliation":[]},{"given":"Joelle","family":"Duplay","sequence":"additional","affiliation":[]},{"given":"Jo\u00e3o","family":"Rocha","sequence":"additional","affiliation":[]},{"given":"Celso","family":"Gomes","sequence":"additional","affiliation":[]}],"member":"56","published-online":{"date-parts":[[2024,2,28]]},"reference":[{"key":"S0009860400023545_CR1","doi-asserted-by":"publisher","DOI":"10.1346\/CCMN.1985.0330104"},{"key":"S0009860400023545_CR39","doi-asserted-by":"publisher","DOI":"10.1346\/CCMN.1992.0400211"},{"key":"S0009860400023545_CR28","doi-asserted-by":"publisher","DOI":"10.1180\/claymin.1994.029.3.01"},{"key":"S0009860400023545_CR36","doi-asserted-by":"publisher","DOI":"10.1007\/BF00199671"},{"key":"S0009860400023545_CR47","doi-asserted-by":"publisher","DOI":"10.1007\/978-1-4615-8612-8"},{"key":"S0009860400023545_CR26","first-page":"598","article-title":"A critique of diffuse double layer models applied to colloid and surface chemistry","volume":"24","author":"McBride","year":"1976","journal-title":"Clays and Clay Minerals"},{"key":"S0009860400023545_CR14","doi-asserted-by":"publisher","DOI":"10.1515\/9781501508998-008"},{"key":"S0009860400023545_CR13","doi-asserted-by":"publisher","DOI":"10.2136\/sssaj1978.03615995004200010033x"},{"key":"S0009860400023545_CR38","doi-asserted-by":"publisher","DOI":"10.1346\/CCMN.1996.0440204"},{"key":"S0009860400023545_CR46","doi-asserted-by":"publisher","DOI":"10.1180\/claymin.1978.013.1.06"},{"key":"S0009860400023545_CR18","doi-asserted-by":"publisher","DOI":"10.1180\/claymin.1954.002.12.03"},{"key":"S0009860400023545_CR15","first-page":"1093","article-title":"How the microfabric of soils may be influenced by the structure and chemical composition of parent minerals","volume":"6","author":"Gilkes","year":"1986","journal-title":"Trans International Soil Science Conference, Hamburg"},{"key":"S0009860400023545_CR41","doi-asserted-by":"publisher","DOI":"10.1346\/CCMN.1976.0240402"},{"key":"S0009860400023545_CR6","first-page":"1621","article-title":"Greisen and post-greisen alteration in the kaolin deposit of S\u00e3o Vicente de Pereira (Portugal)","volume":"36","author":"Bobos","year":"1998","journal-title":"Canadian Mineralogist"},{"key":"S0009860400023545_CR20","doi-asserted-by":"publisher","DOI":"10.1346\/CCMN.1991.0390101"},{"key":"S0009860400023545_CR5","first-page":"237","article-title":"Morphology and structure of endellite and halloysite","volume":"6","author":"Bates","year":"1950","journal-title":"American Mineralogist"},{"key":"S0009860400023545_CR12","doi-asserted-by":"publisher","DOI":"10.1346\/CCMN.1984.0320104"},{"key":"S0009860400023545_CR40","doi-asserted-by":"publisher","DOI":"10.1346\/CCMN.1996.0440614"},{"key":"S0009860400023545_CR25","doi-asserted-by":"publisher","DOI":"10.1180\/mono-5.3"},{"key":"S0009860400023545_CR37","doi-asserted-by":"publisher","DOI":"10.1180\/claymin.1994.029.2.14"},{"key":"S0009860400023545_CR11","doi-asserted-by":"publisher","DOI":"10.1346\/CCMN.1985.0330507"},{"key":"S0009860400023545_CR17","doi-asserted-by":"publisher","DOI":"10.1346\/CCMN.1962.0110122"},{"key":"S0009860400023545_CR10","doi-asserted-by":"publisher","DOI":"10.1180\/claymin.1989.024.4.02"},{"key":"S0009860400023545_CR33","first-page":"3","volume-title":"Proceedings International Clay Conference Tokyo, Volume 1","author":"Range","year":"1969"},{"key":"S0009860400023545_CR9","first-page":"329","article-title":"Cartografia geol\u00f3gica e estratigrafia da faixa prec\u00e2mbrica do sector Espinho\u2014Albergaria-A-Velha (Zona de Ossa-Morena). 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