Highly strained, bridged hydrocarbon; isomer of toluene and quadricyclane, q.q.v. Prepn: J. Hine et al., J. Am. Chem. Soc. 77, 594 (1955) DOI; M. A. Pryanishnikova et al., Russ. Chem. Bull. 16, 1085 (1967) DOI. Microwave structural studies: G. Knuchel et al., J. Am. Chem. Soc. 115, 10845 (1993) DOI. Crystal structure determn: J. Benet-Buchholz et al., Chem. Commun. 1998, 2003 DOI. Review of synthetic applications: B. Hill et al., Mol. Photochem. 5, 195-208 (1973); V. R. Flid et al., Eurasian Chem. Technol. J. 3, 73-90 (2001); of solar energy storage applications of isomerization reaction with quadricyclane: A. D. Dubonosov et al., Russ. Chem. Rev. 71, 917-927 (2002) DOI.