Formulae square brackets

In empirical formulas of inorganic compounds, electropositive elements are listed first [3]. The stoichiometry of the element symbols is indicated at the lower right-hand side by index numbers. If necessary, the charges of ions are placed at the top right-hand side next to the element symbol (e.g., S "). In ions of complexes, the central atom is specified before the ligands are listed in alphabetical order, the complex ion is set in square brackets (e.g., Na2[Sn(OH)+]). 

Free Radicals. In the formula of a polyatomic radical an unpaired electron(s) is(are) indicated by a dot placed as a right superscript to the parentheses (or square bracket for coordination compounds). In radical ions the dot precedes the charge. In structural formulas, the dot may be placed to indicate the location of the unpaired electron(s). 

Enclosing Marks. Where it is necessary in an inorganic formula, enclosing marks (parentheses, braces, and brackets) are nested within square brackets as follows ... 

Generally one uses square brackets to indicate that the formula-weight of the substance, the symbol of which they enclose, is taken in the solid state, round brackets to show that it is in the gaseous state, and no brackets when it is liquid.)... 

The stoichiometiy of a metal complex is described by its chemical formula. For example, each cation of the silver-ammonia complex contains one Ag cation bound to two neutral NH3 ligands and carries a net charge of -i-l, as shown in Figure 18-11. The formula of a complex ion is enclosed in square brackets, as in [ Ag (NH3)2. The... 

The SI primary dimensions and their units are given in Table 1.1, together with their dimensional formulas, denoted by square brackets, and symbols of the units. The number of primary dimensions (7) is one more than required for an absolute system, since... 

According to Jensen, the dimensionality of a structure (or of a substructure of the same) is indicated by enclosing its compositional formula in square brackets and prefixing an appropriate symbol. ... 

In the equations describing enzyme kinetics in this chapter, the notation varies a bit from other chapters. Thus v is accepted in the biochemical literature as the symbol for reaction rate while Vmax is used for the maximum rate. Furthermore, for simplification frequently Vmax is truncated to V in complex formulas (see Equations 11.28 and 11.29). Although at first glance inconsistent, these symbols are familiar to students of biochemistry and related areas. The square brackets indicate concentrations. Vmax expresses the upper limit of the rate of the enzyme reaction. It is the product of the rate constant k3, also called the turnover number, and the total enzyme concentration, [E]o. The case u, = Vmax corresponds to complete saturation of all active sites. The other kinetic limit, = (Vmax/KM)[S], corresponds to Km >> [S], in other words Vmax/KM is the first order rate constant found when the substrate concentration approaches zero ... 

When a reaction occurs between gaseous species or in solution, chemists usually express the reaction rate as a change in the concentration of the reactant or product per unit time. Recall, from your previous chemistry course, that the concentration of a compound (in mol/L) is symbolized by placing square brackets, [ ], around the chemical formula. The equation below is the equation you will work with most often in this section. 

A formula of the PC may be preceded by a quantifier, V or 3. Parentheses are used to avoid confusion when the order of evaluation or the scope of the arguments is important. Parentheses, square brackets and curly brackets are all equivalent, and may be used interchangeably, as long the same type is used to open and close the same term. 

When writing the formula of a complex, the symbol of the metal is written first, then the negatively charged ligands, followed by the neutral ligands. Finally, the formula of the complex ion is enclosed within square brackets as in, for example, [Fe(0H)2(Hp)J+. This ion has an overall charge of -rl as this is the sum of the Fe + ion and the two 0H ions. 

The closed expression for an arbitrary n is calculated in formula (6.14a) in [2], p. 471. While this closed expression is correct, its expansion over Za printed in [2] after an equality sign, contains two misprints. Namely the sign before Za) in the square brackets should be changed to the opposite, and the numerical factor inside these brackets should be —2 instead of —1. After these corrections the expansion in formula (6.14a) in [2] does not contradict the exact expression in the same formula, and also coincides with the result in [1]. 

The main difference between the two theories lies in Werner s assumption that the co-ordinated groups surrounding the central atom are connected with that atom by valency bonds, whereas Friend assumes them to be connected with one another. The accepted method of writing the formula with the central groups within square brackets remains the same in both cases. 

In writing the formula of a "coordinated complex", the "coordinated group , called "nucleus" or the "first sphere" is enclosed in square brackets, while the acid radicals are placed outside in the so-called "second or ionization sphere". For instance in the formula [m Rm], M is a metal (such as Cd,... 

Coordination compounds. [In the formula of a coordination entity.] the symbol of the central atom(s) is placed first, followed by the ionic and then the neutru] ligands. Square brackets are used to enclose the whole coordination entity whether charged or not. This practice need not be used for simple species such us the common oxoanions (NO, NOT, SO -, OH-, etc.). Enclosing marks are nested within the square brackets as follows [()]. U<) , [()]>]. [( [()] ]]. etc. 

Coordination entity. A coordination entity is composed of a central atom, usually that of a metal, to which is attached a surrounding array of other atoms or groups of atoms, each of which is called a ligand. In formulae, (he coordination entity is enclosed in square brackets whether it is charged or uncharged. 

Uses of cnclii,sinj> murks. The formula for the entire coordination enlily. whether charged or not. is enclosed in square brackets. When ligands are polyatomic, their formulae are enclosed in parentheses. Ligand abbreviations are also enclosed in parentheses. In the special case of coordination entities, the nesting order of enclosures is as given [on page A-5I. There should be no space between representations of ionic species within a coordination formula. 

Ionic charges and oxidation numbers. If the formula of a charged coordination entity is to be written without lhat of the counterion, the churge is indicated outside the square bracket as a right superscript, wiih the number before the sign. The oxidation number of a central atom may be represented by a roman numeral used as a right superscript on the element symbol. 

In writing the formula of a "coordinated complex , the "coordinated group , called "nucleus or the "first sphere is enclosed in square brackets, while the acid radicals are placed outside in the so-called "second or ionization sphere . For instance in the formula [M Rml X, M is a metal (such as Cd, Co, Cr, Cu, Fe, Hg, Mn, Ni or Zn), R is a non-ionic(neutral) radical(such as NH3, H20, ethylenediamine, diethylenetriamine, pyridine, etc), m is "coordination number of M, X is a negative(acidic) radical(such as Cl, CN, ... 

In all the following formulas only one resonance structure is shown. To indicate that a jr-electron system with many possible resonance structures is involved, the total charge of the molecule is given outside a square bracket. 

Write the formulas for the named compounds using square brackets to enclose the complex ion. 

The term active mass of a reactant is the molecular concentration, i.e., the number of gram moles per unit volume. It is expressed by enclosing the formula of the substance within two square brackets, e.g., [H2], [HI] etc. 

To write the formula of compounds containing complex ions we make use of square brackets to represent the complex ion, e.g., [Ni. (NH3)6] Br2. In it [Ni (NH3)6]2+ is the complex ions. It indicates that six NH3 are attached directly to Ni. Such complex compounds are called coordination compounds. 

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