Studies on formation of chromium niobates

• Main Authors: Shiva Prasad, Jaqueline V. Barros, Valderí Duarte Leite
• Format: Article
• Language: English
• Published: Sociedade Brasileira de Química 2000-12-01
• Series: Química Nova
• Subjects: niobates; chromium niobates; electrometry
• Online Access: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-40422000000600008

The precise nature of the reaction between chromium chloride and potassium niobate at specific pH levels 12.0, 10.8 and 7.6 has been studied by means of electrometric techniques involving pH and conductometric titrations. The well defined breaks and inflections in the titration curves provide cogent evidence for the formation and precipitation of chromium ortho-Cr2O3.3Nb2 O5, hexa-4Cr2O3.9Nb2 O5 and meta-Cr2O3.3Nb2 O5 niobates in the vicinity of pH 7.5, 6.8 and 5.6, respectively. Analytical investigations of the precipitates have also been carried out which substantiate the results of the electrometric study.