New studies on the chemistry of protoactinium

CONTENTS
I. Introduction 419
II. Isolation of protoactinium from naturally occurring sources 420
III. Artificial preparation of protoactinium-231 422
IV. Methods for the determination of protoactinium 422
V. Extraction of protoactinium by organic solvents 423
VI. Ion exchange, adsorption, and coprecipitation of protoactinium 425
VII. The state of protoactinium in aqueous solutions 426
VIII. Protoactinium and the actinide family 426