Page 37 - Nomenclature of Inorganic Chemistry (IUPAC Recommendations 2005)

G R A M M A R I R-2.5

(c) Centre dots in formulae of (formal) addition c ompounds, i ncluding hydrates, adducts,
clathrates, double s alts and double oxides, separate the individual constituents. The dot is
written i n t he centre of the line to distinguish it from a f ull stop (period).

Examples:

4. BF 3 ·NH 3
5. ZrCl 2 O·8H 2 O
6. CuCl 2 ·3Cu(OH) 2
7. Ta 2 O 5 ·4WO 3
Dots are used in names of radicals t o i ndicate the presence of unpaired electrons.

Examples:
8. ClO * oxidochlorine( * )
*
9. Cl 2 dichloride( * 1 )
IR-2.5.2 Colons

Colons are used in names in the following ways.
(a) In coordination and organometallic compounds, t o s eparate the ligating atoms of a l igand
which bridges central atoms.

Example:
1. [{Co(NH 3 ) 3 } 2 (m-NO 2 )(m-OH) 2 ] 3þ
di-m-hydroxido-m-nitrito-kN:kO-bis(triamminecobalt)(3þ)
(See Sections IR-9.2.4.2 and IR-10.2.3.3 for the use of k, a nd Sections IR-9.2.5.2 and
IR-10.2.3.1 for the use of m.)

(b) In polynuclear coordination and organometallic compounds, to separate the central atom
locants when single ligating atoms or unsaturated groups bind to two or more central atoms.
Thus, a c hloride ligand bridging b etween central atoms 1 a nd 2 w ould be indicated by m-
2
chlorido-1:2k Cl, a nd a c arbonyl group terminally b onded to atom 1 a nd bridging a toms 2
2
2
and 3 via its p electrons would be indicated by m 3 -2Z :3Z -carbonyl-1kC.
(c) In boron compounds, t o s eparate the sets o f l ocants of boron atoms which are connected
by bridging hydrogen atoms.

Example:
2. SiH 3
H B 1 H
5 B B 2
H H H
B B
H 4 3
H H
1-silyl-2,3:2,5:3,4:4,5-tetra-mH-pentaborane(9)

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