Potentiometric and conductometric studies on the system acid-isopolytungstate and the formation of lanthanum tungstates
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| Format: | Artículo científico |
| Language: | en |
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Universidade Estadual Paulista Júlio de Mesquita Filho
2007
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| author | S. Prasad |
| author_facet | S. Prasad |
| contents | Potentiometric and conductometric studies on the system acid-isopolytungstate and the formation of lanthanum tungstates S. Prasad V. D. Leite A. R.N. Campos R. A.C. Santana Química lanthanum polyanions electrometry Isopolytungstates The stoichiometry of the polyanions formed by the action of nitric acid on sodium tungstate (≤ 0.01M) has been studied by means of electrometric techniques involving pH-potentiometric and conductometric titrations. The well defined inflections and breaks in the titration curves provideevidence for the existence of the polyanions, para-W12O41 10- and meta-W12O39 6- corresponding to theratio of H+:WO4 2- as 7:6 and 9:6 in the pH ranges 5.7-6.0 and 3.6-4.1, respectively. The interaction oflanthanum nitrate with sodium tungstate solutions, at specific pH levels 8.0, 5.9 and 4.0 was alsostudied by pH and conductometric titrations, in aqueous and alcoholic media, with each of the reagentsalternatively used as titrant. The electrometric experiments provide definite evidence of the formationof normal-La2O3.3WO3, para-5La2O3.36WO3 and meta-La2O3.12WO3 tungstates in the vicinity of pH6.3, 5.0 and 4.2, respectively. Analytical investigations on the precipitates formed confirm the resultsof the electrometric study. 2007 artículo científico 0100-4670 https://www.redalyc.org/articulo.oa?id=42932110 en http://www.redalyc.org/revista.oa?id=429 Eclética Química application/pdf Universidade Estadual Paulista Júlio de Mesquita Filho Eclética Química (Brasil) Num.1 Vol.32 |
| format | Artículo científico |
| id | redalyc_42932110 |
| institution | Redalyc |
| language | en |
| publishDate | 2007 |
| publisher | Universidade Estadual Paulista Júlio de Mesquita Filho |
| spellingShingle | Potentiometric and conductometric studies on the system acid-isopolytungstate and the formation of lanthanum tungstates S. Prasad Química lanthanum polyanions electrometry Isopolytungstates Potentiometric and conductometric studies on the system acid-isopolytungstate and the formation of lanthanum tungstates S. Prasad V. D. Leite A. R.N. Campos R. A.C. Santana Química lanthanum polyanions electrometry Isopolytungstates The stoichiometry of the polyanions formed by the action of nitric acid on sodium tungstate (≤ 0.01M) has been studied by means of electrometric techniques involving pH-potentiometric and conductometric titrations. The well defined inflections and breaks in the titration curves provideevidence for the existence of the polyanions, para-W12O41 10- and meta-W12O39 6- corresponding to theratio of H+:WO4 2- as 7:6 and 9:6 in the pH ranges 5.7-6.0 and 3.6-4.1, respectively. The interaction oflanthanum nitrate with sodium tungstate solutions, at specific pH levels 8.0, 5.9 and 4.0 was alsostudied by pH and conductometric titrations, in aqueous and alcoholic media, with each of the reagentsalternatively used as titrant. The electrometric experiments provide definite evidence of the formationof normal-La2O3.3WO3, para-5La2O3.36WO3 and meta-La2O3.12WO3 tungstates in the vicinity of pH6.3, 5.0 and 4.2, respectively. Analytical investigations on the precipitates formed confirm the resultsof the electrometric study. 2007 artículo científico 0100-4670 https://www.redalyc.org/articulo.oa?id=42932110 en http://www.redalyc.org/revista.oa?id=429 Eclética Química application/pdf Universidade Estadual Paulista Júlio de Mesquita Filho Eclética Química (Brasil) Num.1 Vol.32 |
| title | Potentiometric and conductometric studies on the system acid-isopolytungstate and the formation of lanthanum tungstates |
| topic | Química lanthanum polyanions electrometry Isopolytungstates |
| url | https://www.redalyc.org/articulo.oa?id=42932110 |