Experimental charge-density study on the nickel(II) coordination complex [Ni(H<sub>3</sub> <i>L</i>)][NO<sub>3</sub>][PF<sub>6</sub>] [H<sub>3</sub> <i>L</i> = <i>N</i>,<i>N</i>′,<i>N</i>′′-tris(2-hydroxy-3-methylbutyl)-1,4,7-triazacyclononane]: a reappraisal
Acta crystallographica. Section B, Structural science