Is stearic acid ionic or covalent

Chapter 28

Inorganic chemical products; inorganic or organic compounds of precious metals, radioactive elements, rare earth metals or isotopes

General

Unless otherwise specified, Chapter 28 only includes isolated chemical elements (basic substances) or isolated chemically uniform compounds.

An isolated chemically uniform compound is a substance which consists of a certain type of molecule (covalent or ionic) and whose composition is defined by the regular repetition of its elements and which can be represented by a single structural diagram. In the crystal lattice, the type of molecule corresponds to a repeating pattern.

The elements of an isolated chemically uniform compound are present in characteristic proportions, given by the valency of the atoms present and by the type of atomic connections. Because for every connection every element is present in a constant and characteristic, the so-called stoichiometric ratio.

The stoichiometric repetition of certain compounds is sometimes slightly changed by gaps and inclusions in the crystal lattice. These quasi-stoichiometric compounds can only be classified as isolated chemically uniform compounds if these changes were not made on purpose.

A) Â Â Chemically uniform compounds

(Note 1 to this chapter)

Chapter 28 includes chemically uniform compounds, even if they contain impurities and even aqueous solutions of such compounds.

The term impurities refers exclusively to substances whose presence, in addition to the specific chemical compound, results exclusively and directly from the manufacturing process (including cleaning). These substances can occur as a result of factors associated with manufacturing; these are essentially the following:

a) Â Â Â Unconverted raw materials.

b) Â Â Â Impurities contained in the raw materials.

c) Reaction components used in the manufacturing process (including cleaning).

d) Â Â Â By-products.

It should be noted, however, that such substances may not always be regarded as contaminants permitted by Note 1 a). If such substances are intentionally left in the product in order to make it more suitable for a specific purpose than for general use, they are not considered to be contaminants whose presence is permissible.

Chapter 28 does not, however, include solutions of such compounds other than aqueous solutions, unless the presentation in such solutions is customary and required solely for safety or transport reasons, and the addition of the Solvent does not make the product more suitable for specific uses than general use.

For example, carbon oxychloride dissolved in benzene, ammonia dissolved in alcohol and aluminum in colloidal dispersion are excluded from Chapter 28; they belong to No. 3824. In addition, colloidal dispersions generally belong to No. 3824 if they are not recorded more precisely by another number.

Isolated chemical elements and those compounds that are regarded as chemically uniform according to the above rules can be mixed with a stabilizing agent if this is necessary for their preservation or for their transport (e.g. hydrogen peroxide stabilized with boric acid remains in No. 2847; but sodium peroxide, which is combined with catalysts and is used to produce hydrogen peroxide, is on the other hand excluded from Chapter 28 and belongs to No. 3824).

Substances that are added to certain chemical products in order to retain their original physical state are also to be regarded as stabilizing agents, provided that the amount added does not exceed what is necessary for the intended purpose, nor does it affect the character of the chemical product And in particular does not make it more suitable for certain purposes than for general use. Substances that prevent agglomeration may also be added to the products in this chapter under the aforementioned conditions. On the other hand, this subheading does not include products to which substances with hydrophobic properties have been added because these substances change the character of the original products.

Also provided that the addition does not make them more suitable for certain purposes than for general use, the products in this chapter can also contain:

a) Anti-dust agent (e.g. an addition of mineral oil to certain toxic chemical products to prevent the generation of dust during manipulation);

b) Â Â Â Colorants that are added to dangerous or toxic substances for labeling or for safety reasons (lead arsenate of No. 2842, in particular) in order to provide clues or to warn people who handle these substances. This does not apply to products to which dyes have been added for purposes other than those mentioned above. This is the case, for example, with silica gel to which cobalt salts have been added as a moisture indicator (No. 3824).

B) Distinction between the connections of chapters 28 and 29

(Note 2 to this chapter)

Of the carbon compounds only those mentioned below belong to Chapter 28 in the following numbers:

2811

-

Carbon oxides.

Hydrocyanic acid (hydrocyanic acid), hexacyanoiron (II) acid and hexacyanoiron (III) acid.

Isocyanic acid, oxyhydrogen, hydrocyanic acid, cyanomolybdic acid and other simple or complex hydrocyanic acids.

2812

-

Hydrocarbon oxyhalides.

2813

-

Carbon disulfide.

2831

-

Dithionites and sulfoxylates stabilized by organic substances.

2836

-

Carbonates and peroxocarbonates of inorganic bases.

2837

-

Simple cyanides, complex cyanides and oxycyanides of inorganic bases (hexacyanoferrates (II), hexacyanoferrates (III), nitrosylpentacyanoferrates (II), nitrosylpentacyanoferrates (III), cyanomanganates, cyanocadmates, cyanochromates, cyanocupcolates, etc.).

2842

-

Thiocarbonates, seleniocarbonates and tellurocarbonates; Seleniocyanates and tellurocyanates; Tetrathiocyanodiamminochromate (Reineckate) and other complex cyanates of inorganic bases.

2843

-

Inorganic or organic compounds:

to

1. the precious metals;

2846

2. the radioactive elements;

3. the isotopes;

4. the rare earth metals, yttrium and scandium.

2847

-

Hydrogen peroxide, solidified with urea, also stabilized.

2849

-

Carbides (binary boron carbides, etc.), excluding hydrocarbons.

2852

2853

-

-

Inorganic or organic compounds of mercury, excluding amalgams.

Carbon oxysulfide.

Thiocarbonyl halides.

Cyan and its halides.

Cyanamide and its metal derivatives (with the exception of calcium cyanamide, also pure - see Chapter 31).

All other carbon compounds do not belong in Chapter 28.

C) Products that belong to Chapter 28, even if they don't
Elements or chemically uniform compounds are.

There are a few exceptions to the rule that elements and compounds belong to Chapter 28 only if they are chemically uniform. These exceptions, which result from the nomenclature itself, apply in particular to the following products:

2802

-

Colloidal sulfur.

2803

-

Soot.

2807

-

Oleum.

2808

-

Nitrating acids.

2809

-

Polyphosphoric acids.

2813

-

Phosphorus trisulfide.

2818

-

Artificial corundum.

2821

-

Color earth with a content of bound iron, calculated as Fe2O3, of 70 percent by weight or more.

2822

-

Commercially available cobalt oxides.

2824

-

Red lead and orange lead.

2828

-

Commercially available calcium hypochlorite.

2830

-

Polysulfides.

2831

-

Dithionites and sulfoxylates stabilized by organic substances.

2835

-

Polyphosphates.

2836

-

Commercially available ammonium carbonate containing ammonium carbamate.

2839

-

Commercially available silicates of the alkali metals.

2842

Aluminosilicates

2843

-

Precious metals in a colloidal state

- precious metal amalgams

- inorganic or organic compounds of precious metals

2844

-

Radioactive elements, radioactive isotopes or compounds (organic or inorganic) as well as mixtures containing such substances.

2845

-

Other isotopes and their organic or inorganic compounds.

2846

-

Inorganic or organic compounds of rare earth metals, yttrium, or scandium or mixtures of these metals.

2848

-

Phosphides.

2849

-

Carbides.

2850

-

Hydrides, nitrides, azides, silicides and borides.

2853

-

Liquid air and compressed air.