(chemistry) Any compound containing a cation of general formula R₄As⁺; the arsenic analogue of quaternary ammonium compounds.

(chemistry) any polycyclic compound having the form of a cage

(chemistry) Any compound having two or more rings interconnected like the links of a chain, without a covalent bond.

(chemistry) any compound of general formula RN=N-NR₂ where not all R = H

(chemistry) any compound of general formula R₂C=N⁺=N⁻

(chemistry) any compound having the general formula R-N₂⁺ X⁻, especially one in which R is an aryl residue; they are important as intermediates in the production of azo dyes

(chemistry) Any chemical compound in which the number of atoms of each element is not expressible as the ratio of small integers; normally due to missing atoms in a solid state lattice.

(obsolete, organic chemistry) Synonym of oxime

(chemistry) any compound in which a metal atom is located between the faces of two planes of atoms, especially between two rings

(organic chemistry) Any polycyclic compound having a single atom (usually carbon) as the only common member of two rings.