Electrometric investigations on formation of lanthanum molybdates as a function of Ph

Journal of the Brazilian Chemical Society

Universidade Estadual da Paraíba, Campina Grande, Brazil¹  Prasad, Shiva¹  Brito, Joelma B.¹  Universidade Federal de Campina Grande, Campina Grande, Brazil¹  Santana, Renato A.C. de¹  Leite, Valderí D.¹ 

关键词: molybdates;    lanthanum molybdates;    electrometry;   

DOI  :  10.1590/S0103-50532004000200014

学科分类：化学（综合）

来源: SciELO

【 摘 要 】

The precise nature of the reaction between lanthanum nitrate and sodium molybdate at specific pH levels 7.6, 5.5 and 4.1 has been studied by means of electrometric techniques involving potentiometric and conductometric titrations, in aqueous and alcoholic media using each reagent as titrant. Well-defined breaks and inflections in the titration curves provide cogent evidence for formation and precipitation of lanthanum normal-La2O3.3MoO3, para- La2O3.7MoO3 and octa-2 La2O3.24MoO3 molybdates in the vicinity of pH 5.9, 4.8 and 4.2, respectively. Analytical investigations of the precipitates of lanthanum molybdates have also been carried out, which substantiate the results of the electrometric study.

【 授权许可】

Unknown