21-Crown-7

21-Crown-7 is an organic compound with the formula (C₂H₄O)₇. Similar to other crown ethers, 21-crown-7 functions as a ligand for certain metal cations, with a specific affinity for caesium cations.^[1] The dipole moment of 21-crown-7 varies depending on the solvent and temperatures.

21-Crown-7

Skeletal formula
Names
Preferred IUPAC name 1,4,7,10,13,16,19-Heptaoxacyclohenicosane
Identifiers
CAS Number	33089-36-0 Y
3D model (JSmol)	Interactive image
ChemSpider	84104 Y
ECHA InfoCard	100.046.689
EC Number	251-373-3
PubChem CID	93160
UNII	GF978SJ9Z2 Y
CompTox Dashboard (EPA)	DTXSID50186747
InChI InChI=1S/C14H28O7/c1-2-16-5-6-18-9-10-20-13-14-21-12-11-19-8-7-17-4-3-15-1/h1-14H2 Y Key: XKEHLMZHBXCJGZ-UHFFFAOYSA-N Y InChI=1S/C14H28O7/c1-2-16-5-6-18-9-10-20-13-14-21-12-11-19-8-7-17-4-3-15-1/h1-14H2 Key: XKEHLMZHBXCJGZ-UHFFFAOYSA-N
SMILES O1CCOCCOCCOCCOCCOCCOCC1
Properties
Chemical formula	C14H28O7
Molar mass	308.371 g·mol−1
Related compounds
Related compounds	Dibenzo-21-crown-7
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). Infobox references