Tetraaquabis{μ<sub>2</sub>-2,7-bis[(2,6-diisopropylphenyl)iminomethyl]naphthalene-1,8-diolato}di-μ<sub>3</sub>-hydroxido-di-μ<sub>2</sub>-hydroxido-bis(trimethylphosphine oxide)tetranickel(II)–trimethylphosphine oxide–diethyl ether–water (1/2/2/2)
Acta crystallographica. Section E