Potentiometric and conductometric studies on the system acid-isopolytungstate and the formation of lanthanum tungstates
Autor(a) principal: | |
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Data de Publicação: | 2007 |
Outros Autores: | , , |
Tipo de documento: | Artigo |
Idioma: | eng |
Título da fonte: | Eclética Química |
Texto Completo: | http://old.scielo.br/scielo.php?script=sci_arttext&pid=S0100-46702007000100010 |
Resumo: | 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 provide evidence for the existence of the polyanions, para-W12O41(10-) and meta-W12O39(6-) corresponding to the ratio 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 of lanthanum nitrate with sodium tungstate solutions, at specific pH levels 8.0, 5.9 and 4.0 was also studied by pH and conductometric titrations, in aqueous and alcoholic media, with each of the reagents alternatively used as titrant. The electrometric experiments provide definite evidence of the formation of normal-La2O3.3WO3, para-5La2O3.36WO3 and meta-La2O3.12WO3 tungstates in the vicinity of pH 6.3, 5.0 and 4.2, respectively. Analytical investigations on the precipitates formed confirm the results of the electrometric study. |
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Potentiometric and conductometric studies on the system acid-isopolytungstate and the formation of lanthanum tungstatesisopolytungstateslanthanumelectrometrypolyanionsThe 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 provide evidence for the existence of the polyanions, para-W12O41(10-) and meta-W12O39(6-) corresponding to the ratio 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 of lanthanum nitrate with sodium tungstate solutions, at specific pH levels 8.0, 5.9 and 4.0 was also studied by pH and conductometric titrations, in aqueous and alcoholic media, with each of the reagents alternatively used as titrant. The electrometric experiments provide definite evidence of the formation of normal-La2O3.3WO3, para-5La2O3.36WO3 and meta-La2O3.12WO3 tungstates in the vicinity of pH 6.3, 5.0 and 4.2, respectively. Analytical investigations on the precipitates formed confirm the results of the electrometric study.Fundação Editora da Universidade Estadual Paulista Júlio de Mesquita Filho - UNESP2007-01-01info:eu-repo/semantics/articleinfo:eu-repo/semantics/publishedVersiontext/htmlhttp://old.scielo.br/scielo.php?script=sci_arttext&pid=S0100-46702007000100010Eclética Química v.32 n.1 2007reponame:Eclética Químicainstname:Universidade Estadual Paulista Júlio de Mesquita Filho (UNESP)instacron:UNESP10.1590/S0100-46702007000100010info:eu-repo/semantics/openAccessPrasad,S.Santana,R. A.C.Campos,A. R.N.Leite,V. D.eng2007-06-04T00:00:00Zoai:scielo:S0100-46702007000100010Revistahttp://revista.iq.unesp.br/ojs/index.php/ecletica/PUBhttps://revista.iq.unesp.br/ojs/index.php/ecletica/oaiecletica@ctrlk.com.br||ecletica@iq.unesp.br1678-46181678-4618opendoar:2007-06-04T00:00Eclética Química - Universidade Estadual Paulista Júlio de Mesquita Filho (UNESP)false |
dc.title.none.fl_str_mv |
Potentiometric and conductometric studies on the system acid-isopolytungstate and the formation of lanthanum tungstates |
title |
Potentiometric and conductometric studies on the system acid-isopolytungstate and the formation of lanthanum tungstates |
spellingShingle |
Potentiometric and conductometric studies on the system acid-isopolytungstate and the formation of lanthanum tungstates Prasad,S. isopolytungstates lanthanum electrometry polyanions |
title_short |
Potentiometric and conductometric studies on the system acid-isopolytungstate and the formation of lanthanum tungstates |
title_full |
Potentiometric and conductometric studies on the system acid-isopolytungstate and the formation of lanthanum tungstates |
title_fullStr |
Potentiometric and conductometric studies on the system acid-isopolytungstate and the formation of lanthanum tungstates |
title_full_unstemmed |
Potentiometric and conductometric studies on the system acid-isopolytungstate and the formation of lanthanum tungstates |
title_sort |
Potentiometric and conductometric studies on the system acid-isopolytungstate and the formation of lanthanum tungstates |
author |
Prasad,S. |
author_facet |
Prasad,S. Santana,R. A.C. Campos,A. R.N. Leite,V. D. |
author_role |
author |
author2 |
Santana,R. A.C. Campos,A. R.N. Leite,V. D. |
author2_role |
author author author |
dc.contributor.author.fl_str_mv |
Prasad,S. Santana,R. A.C. Campos,A. R.N. Leite,V. D. |
dc.subject.por.fl_str_mv |
isopolytungstates lanthanum electrometry polyanions |
topic |
isopolytungstates lanthanum electrometry polyanions |
description |
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 provide evidence for the existence of the polyanions, para-W12O41(10-) and meta-W12O39(6-) corresponding to the ratio 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 of lanthanum nitrate with sodium tungstate solutions, at specific pH levels 8.0, 5.9 and 4.0 was also studied by pH and conductometric titrations, in aqueous and alcoholic media, with each of the reagents alternatively used as titrant. The electrometric experiments provide definite evidence of the formation of normal-La2O3.3WO3, para-5La2O3.36WO3 and meta-La2O3.12WO3 tungstates in the vicinity of pH 6.3, 5.0 and 4.2, respectively. Analytical investigations on the precipitates formed confirm the results of the electrometric study. |
publishDate |
2007 |
dc.date.none.fl_str_mv |
2007-01-01 |
dc.type.driver.fl_str_mv |
info:eu-repo/semantics/article |
dc.type.status.fl_str_mv |
info:eu-repo/semantics/publishedVersion |
format |
article |
status_str |
publishedVersion |
dc.identifier.uri.fl_str_mv |
http://old.scielo.br/scielo.php?script=sci_arttext&pid=S0100-46702007000100010 |
url |
http://old.scielo.br/scielo.php?script=sci_arttext&pid=S0100-46702007000100010 |
dc.language.iso.fl_str_mv |
eng |
language |
eng |
dc.relation.none.fl_str_mv |
10.1590/S0100-46702007000100010 |
dc.rights.driver.fl_str_mv |
info:eu-repo/semantics/openAccess |
eu_rights_str_mv |
openAccess |
dc.format.none.fl_str_mv |
text/html |
dc.publisher.none.fl_str_mv |
Fundação Editora da Universidade Estadual Paulista Júlio de Mesquita Filho - UNESP |
publisher.none.fl_str_mv |
Fundação Editora da Universidade Estadual Paulista Júlio de Mesquita Filho - UNESP |
dc.source.none.fl_str_mv |
Eclética Química v.32 n.1 2007 reponame:Eclética Química instname:Universidade Estadual Paulista Júlio de Mesquita Filho (UNESP) instacron:UNESP |
instname_str |
Universidade Estadual Paulista Júlio de Mesquita Filho (UNESP) |
instacron_str |
UNESP |
institution |
UNESP |
reponame_str |
Eclética Química |
collection |
Eclética Química |
repository.name.fl_str_mv |
Eclética Química - Universidade Estadual Paulista Júlio de Mesquita Filho (UNESP) |
repository.mail.fl_str_mv |
ecletica@ctrlk.com.br||ecletica@iq.unesp.br |
_version_ |
1754734618086473728 |