Covalent radii of four-co-ordinate copper(I), silver(I) and gold(I): crystal structures of [Ag(AsPh3)4]BF4 and [Au(AsPh3)4]BF4
Abstract
The complexes [Ag(AsPh
3
)
4
]BF
4
and
[Au(AsPh
3
)
4
]BF
4
were prepared from
AgBF
4
and 4 equivalents of AsPh
3
, and from
equimolar quantities of [Au(AsPh
3
)Cl] and AgBF
4
and 3 equivalents of AsPh
3
, respectively, in dichloromethane
solution. Single crystals of the two compounds are isomorphous
(trigonal, space group R![[3 with combining macron]](https://www.rsc.org/images/entities/char_0033_0304.gif)
,
Z = 6) and contain cations with a tetrahedral
Ag/Au–As
4
core. From the Ag/Au–As distances
measured at 199 K the covalent radii of four-co-ordinate
silver(I) and gold(I) have been calculated using
an accepted standard covalent radius for four-co-ordinate
arsenic(III),
r(As
III
) = 1.20 Å;
r(Au
I
) = 1.37 Å is found to be
6% smaller than r(Ag
I
) = 1.46 Å.
This contraction reflects the strong influence of relativistic effects
on atomic radii. From other data, r(Cu
I
) for
four-co-ordinate copper is estimated to be 1.29 Å.
,
Z = 6) and contain cations with a tetrahedral
Ag/Au–As
4
core. From the Ag/Au–As distances
measured at 199 K the covalent radii of four-co-ordinate
silver(I) and gold(I) have been calculated using
an accepted standard covalent radius for four-co-ordinate
arsenic(III),
r(As
III
) = 1.20 Å;
r(Au
I
) = 1.37 Å is found to be
6% smaller than r(Ag
I
) = 1.46 Å.
This contraction reflects the strong influence of relativistic effects
on atomic radii. From other data, r(Cu
I
) for
four-co-ordinate copper is estimated to be 1.29 Å.
Please wait while we load your content...
