Chemical notations that need to be accepted

From IUPAC's Red Books (2005):

Formulae of optically active compounds
> The sign of optical rotation is placed in parentheses, the wavelength (in nm) being indicated
> as a right subscript. The whole symbol is placed before the formula and refers to the sodium
> D-line unless otherwise stated.
> Example: $(+)_{589}-[\rm{Co(en)}_3]Cl_3$

Indication of excited states
>Excited electronic states may be indicated by an asterisk as right superscript. This practice
> does not differentiate between different excited states.
> Example $\rm{He}^*$

Structural descriptors
> Structural descriptors such as cis, trans, etc., are listed in Table V. Usually such descriptors
> are used as italicized prefixes and are connected to the formula by a hyphen.
> Examples:
> 1. cis-[PtCl2(NH3)2]
> 2. trans-[PtCl4(NH3)2]