Unprimed numbering

If there is a choice in numbering, unprimed numbers are assigned to the system which has the lower-numbered point of attachment. 

If two identical hydrocarbon systems have the same point of attachment and contain substituents at different positions, the locants of these substituents are assigned according to Rule A-2.2 for this purpose an unprimed number is considered lower than the same number when primed. Assemblies of primed and unprimed numbers are arranged in ascending numerical order. 

Unprimed numbers are assigned to one of the terminal systems, the other systems being primed serially. Points of attachment are assigned the lowest numbers possible. 

In a compound name for a fusion prefix when more than one pair of square brackets is required), the points of fusion in the compound prefix are indicated by the use of unprimed and primed numbers, the unprimed numbers being assigned to the ring attached directly to the base component, thus ... 

Figure 3. Calculated properties of hydride of BCC metal (atomic radius unity) as a function of relative radius R of hydrogen in one tetrahedral site on face, alternating (0,1/2, 3/4) and (1/2, 0,1/4) Unprimed numbers refer to case where metal atoms are at minimum separation primed numbers to case of minimum molar volume...

The numbering of the assembly is that of the component system. One terminal component is assigned unprimed numbers as locants, the locants of the other components being primed serially. 

The priority numbers on one of the ligands are arbitrarily primed. The primed number is assigned lower priority than the corresponding unprimed number, but a higher priority than the next higher unprimed number. Thus 1 has lower priority than 1, but higher than 2. 

Figure 1 is a reminder that a nucleic acid molecule consists of a backbone of ribose and phosphate, to which the various heterocyclic bases are attached. The sequence of these bases, of course, constitutes the genetic code. The primes are used in numbered positions of the ribose whereas the unprimed numbers refer to the numbering in the heterocyclic bases. The two diflFerent nucleic add molecules, DNA (deoxyribonucleic acid) and RNA (ribonucleic acid), diflFer by the presence or absence of the 2 -hydroxyl groups. RNA contains the 2 -hydroxyl groups DNA does not. 

NB The substitutions indicated in the first column that are primed numbers refer to one phenyl ring, while unprimed numbers are die corresponding positions on the other ring. 

A cyclic cluster is defined as a superceU with identical opposite faces, i.e. the periodic boundary conditions are introduced for the chosen supercell itself (not for the main region of a crystal ). In particular, in the supercell, shown on Fig. 6.1a, the atoms with the primed numbers are supposed to be identical with the atoms of the superceU, having the same unprimed numbers. This means that the translation of a superceU as a whole is equivalent to the zero translation. 

The numbering of the positions of substitution of oligosaccharides uses the numbering of the carbons of individual monosaccharide units in the oligosaccharide, with the first unit in the systematic name being given numbers with primes. This is especially so for the nonreducing disaccharides. The order is unprimed numbers with the lowest numbers first, followed by the primed numbers with the... 

Spirans, if completely symmetrical (excluding substituents), are simply named as, for example, spirobi(cyclohexane) (XVII), or l,l -spirobi-indene (XVIII), with primed and unprimed numbers. Un-symmetrical spirans may receive names of the type... 

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