The invention relates to new calixarenes according to the formula: ##STR1## wherein: R.sup.1 is an alkyl or aryl group, or a hydrogen atom, R.sup.2 and R.sup.3, which may be identical or different, are alkyl or aryl groups, n is an integer ranging from 2 to 8, and p is an integer ranging from 4 to 8. Said calixarenes may be used to extract actinides and lanthanides from aqueous solutions.