This paper proposes a description of maximally entangled bipartite states within the algebra of biquaternions-Ä . We assume that a bipartite entanglement is created in a process of splitting one particle into a pair of two indiscernible, yet not identical particles. As a result, we describe an entangled correlation by the use of a division relation and obtain twelve forms of biquaternions, representing pure maximally entangled states. Additionally, we obtain other patterns, describing mixed entangled states. Finally, we show that there are no other maximally entangled states in Ä than those presented in this work.1 2 1 2 3 4 because these two sets have different elements, and a set is uniquely determined by its elements.Mereology, as a collective set theory, takes into consideration relations between elements. In comparison, ZFC set theory neglects such connections, i.e., we have abstract wholes in which elements are treated as independent entities. Having in mind entanglement, we incorporated a kind of an entangled correlation and made it a founding relation in NAM. We analyzed properties of the obtained model and incorporated ZFC set theory within NAM [19]. Moreover, we represented NAM in terms of non-classic algebras [20]. Finally, we were able to express a bipartite entanglement by the use of quaternions [17]. The novelty of the proposed model stands in the fact that in an investigated universe we can have classical atoms and indecomposable, but composite atoms represented by entanglement, which are not elements of classical ZFC set theory.Original content from this work may be used under the terms of the Creative Commons Attribution 4.0 licence.Any further distribution of this work must maintain attribution to the author(s) and the title of the work, journal citation and DOI.1 NAM=Non-Antisymmetric Mereology. It is a model of mereology in which we assume that the inclusion relation-⊆ is only reflexive and transitive. We deny the antisymmetry of ⊆. 2 The ZFC set theory is a classical model of set theory. The abbreviation-ZFC follows from the names of mathematicians, which contributed to developing this model: E. Zermelo and A.Fraenkel. 'C' stands for the Axiom of Choice taken into consideration in ZFC. This model forms a basis of exact sciences.