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Unformatted text preview: PHYSICAL CONSTANTS OF INORGANIC COMPOUNDS The compounds in this table were selected on the basis of their laboratory and industrial importance, as well as their value in illus- trating trends in the variation of physical properties with position in the periodic table. An effort has been made to include the most frequently encountered inorganic substances; a limited number of organometallics are also covered. Many, if not most, of the com- pounds that are solids at ambient temperature can exist in more than one crystalline modification. In the absence of other infor- mation, the data given here can be assumed to apply to the most stable or common crystalline form. In many cases however, two or more forms are of practical importance, and separate entries will be found in the table. Compounds are arranged primarily in alphabetical order by the most commonly used name. However, adjustments are made in many instances so as to bring closely related compounds togeth- er. For example, hydrides of elements such as boron, silicon, and germanium are grouped together immediately following the entry for the parent element, since they would otherwise be scattered throughout the table. Likewise, the oxoacids of an element are giv- en in one group whenever a strict alphabetical order would sepa- rate them (e.g., sulfuric acid and fluorosulfuric acid). The Formula Index following the table provides another means of locating a compound. There is also an index to CAS Registry Numbers. The following data fields appear in the table: •¡ Name : Systematic name for the substance. The valence state of a metallic element is indicated by a Roman numer- al, e.g., copper in the +1 state is written as copper(I) rather than cuprous, iron in the +3 state is iron(III) rather than ferric. •¡ Formula : The simplest descriptive formula is given, but this does not necessarily specify the actual structure of the compound. For example, aluminum chloride is designated as AlCl 3 , even though a more accurate representation of the structure in the solid phase (and, under some con- ditions, in the gas phase) is Al 2 Cl 6 A few exceptions are made, such as the use of Hg 2 +2 for the mercury(I) ion. •¡ CAS Registry Number : Chemical Abstracts Service Registry Number. An asterisk* following the CAS RN for a hydrate indicates that the number refers to the anhydrous compound. In most cases the generic CAS RN for the compound is given rather than the number for a specific crystalline form or mineral. •¡ Mol. Weight : Molecular weight (relative molar mass) as calculated with the 2005 IUPAC Recommended Atomic Weights. The number of decimal places corresponds to the number of places in the atomic weight of the least accu- rately known element (e.g., one place for lead compounds, two places for compounds of selenium, germanium, etc.); a maximum of three places is given. For compounds of radioactive elements for which IUPAC makes no recom- mendation, the mass number of the isotope with longest...
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- pH, Orth, Ammonium compounds, H2O sl H2O, H2O reac H2O, H2O vs H2O