Internal volumes (ų) in [6]CPP²⁻, [8]CPP²⁻, [10]CPP²⁻, and [12]CPP²⁻.

	[6]CPP2−a	[8]CPP2−	[10]CPP2−	[12]CPP2−
V void b	233	608	1261	1928
Moiety	THF ×2	½{K+(18-crown-6)} ×2	{K+(18-crown-6)} ×2	{K+(benzo-15-crown-5)2} ×2
V moiety c	200	380	760	1760
Host–guest formula	{THF}2⊂[6]CPP2−	½{K+(18-crown-6)}2⊂[8]CPP2−	{K+(18-crown-6)}2⊂[10]CPP2−	{K+(benzo-15-crown-5)2}2⊂[12]CPP2−

^a Ref. 52.

^b V _void ≈ 4/3 × π × (d_min/2 × cos a_min)² × (d_max/2 × cos a_max).

^c V _moiety ≈ N × 20. N is the number of non-hydrogen atoms in the moiety.