Table 1. Four starting models containing the α-Keggin clusters used with Cluster­Finder to extract an α-Keggin cluster.

Starting model	Crystal composition	Reference
1	[Hpy]4H2[H2W12O40] (py = pyridine)	Niu et al. (2004 ▸)
2	[(CH3)4N]4SiW12O40	Joachim et al. (1981 ▸)
3	([(CH3)2NH2]6{Cu[HCON(CH3)2]4}(GeW12O40)2)[HCON(CH3)2]2	Niu et al. (2003 ▸)
4	[(CH3)2NH2]3(PW12O40)	Busbongthong & Ozeki (2009 ▸)