States of water associated with electrodeposited manganese dioxide as revealed by pyknometric density measurements

Abstract

The densities of different states of water associated with an electrodeposited manganese dioxide have been estimated from the original density of the manganese dioxide, the weight of water removed by outgassing and the outgassed density. Outgassing at room temperature removed water which in the associated state had the density of normal water. This water resided in the second and outer physisorbed layers and required two days' outgassing for complete removal. Temperatures of 60–120°C were necessary to remove further water which in the associated state had a density of about 1.25 g cm −3. This water is considered to be ordered or structured and in its amount corresponded to a monolayer. After removal this ordered layer required several days of immersion in water to reform. Outgassing at 170–250°C caused condensation of hydroxyl groups, and products resulting from such treatments reacted slowly with water on immersion.