Digital Exhibit - Elements of Inorganic Chemistry; Including the Applications of the Science in the Arts
Avery Riggs
Annotated and edited by: Avery Riggs
Introduction
The text that I am transcribing is an 1800’s book written by Thomas Graham addressing many elements of inorganic chemistry. The specific part of this text that this transcription will focus on is chemical nomenclature. Thomas Graham was a professor and chemist, known for his work with diffusion of gases and his development of “Graham’s Law”. Graham taught chemistry at Anderson’s Medical School, Glasgow Mechanic’s Institution, and the University of London. He had been appointed many awards such as the Keith Medal or his publications on gaseous diffusion and was referred to as “the father of colloid chemistry” He devoted his life to chemical discoveries and producing research on chemical advancements.
While transcribing pages 106-110 of this text, I replaced outdated terminology with what is used in inorganic chemistry today. As Graham mentions in this transcription, the fundamentals of chemical nomenclature cannot be altered without causing great inconvenience, which is why there is so little that has changed. With that said, modern nomenclature has change slightly only for the purpose of convenience and simplification, names became shorter and ordering of names changed, but it is still referring to the same compound Graham is addressing. Graham was also British, so I changed the spelling of some words to match the English we are familiar with today.
Transcription
The names of newer metals; platinum, potassium, vanadium, etc., have a common terminology, that distinguishes them as metals. Another class of elements like chlorine, iodine, bromine, and fluorine, are named in a similar manner.
The names of compounds are designed to describe their composition and the class they belong to. Compound names are founded on three criteria, the first one is compounds of one element combined with another element. For example, oxygen with sulfur in sulfuric acid, or oxygen with sodium in soda, these are called binary compounds. The second classification combines two binary compounds like sulfuric acid with soda in Glauber’s salt, results in the classification called ternary compounds. The third classification is the combination of salts, such as alum, which is a salt that contains one or more cation or anion, this is called a quaternary compound.
- Of the compounds listed in the first order, oxygen was one of the two
constituents, therefore, an exclusive nomenclature importance was attached to oxygen. The compounds with other elementary bodies are then divided by their properties into (a) the class of neutral bodies and bases, and (b) the class of the acids.
(a) To members of the first class the term oxide was applied, the first syllable to
represent oxygen, with an ending of “ide” to represent the combination of another element to oxygen. A compound of oxygen and hydrogen is called hydrogen oxide, or water, oxygen and potassium is called potassium oxide. In these compounds, oxygen is listed second because it is a nonmetal, and potassium is listed first because it is a metal. But the same elementary body often combines with oxygen in more than one proportion, forming two or more oxides. To distinguish which Greek prefix mono- (one) is applied to the oxide containing one atom of oxygen in the compound, di (two) is applied to the oxide containing two atoms of oxygen, and tri (three) is applied to the oxide containing three atoms of oxygen, and so on. The last oxygen, containing the largest proportion of oxygen uses the common name peroxide, from the Latin prefix “per”, which means intensity. So, the three compounds of manganese and oxygen are named as follows:
Names………………………Manganese Conc………Oxygen Conc.
Manganese Monoxide…………….100…………………..28.91
Manganese Dioxide……………….100………………….43.36
Manganese Peroxide………………100………………….57.82
As the prefix “per” implies the highest degree of oxidation, it may be applied to the second oxide where there are only two, for example the oxides of iron, the second oxide is called deutoxide or peroxide of iron. M. Thenard, in his Traité de Chimie, avoids the use of the term “deutoxide”, and confined the application of peroxide to such of these oxides as, like manganese peroxide, do not combine with acids. He applies the names sesquioxide and dioxide to oxides, which are capable of combining with acids. He has thus manganese monoxide, sesquioxide, and peroxide, as well as iron monoxide, sesquioxide, and peroxide. This pattern continues with different metals. This naming is useful and will be adopted into present work. Inferior oxides, which do not combine with acids are named suboxides, which means there is more metal present than oxygen in the compound.
The compounds of chlorine and other nonmetal elements are named the same was as oxides. Such elements resemble oxygen in many aspects, but most prominently in their electronegativity.
Chlorine, for example has a positive charge similarly to oxygen, and is therefore classed with oxygen as an electronegative substance, in a division of elements categorized by their electronegative values. Thus, with other similar elements,
Oxygen……….. forms ……….oxides
Chlorine..……….. “………..chlorides
Bromine...….…….”….…….bromides
Iodine……………”….……....iodides
Sulfur…………….”...……….sulfides
Phosphorus………” …….phosphides
Carbon…..………”..………carbides
Nitrogen…………”..………..nitrides
Hydrogen……….” ………..hydrides
Cyanogen (C2N2)..”……… cyanides
Sulfate(SO4).……”……….sulfides
For cyanogen and sulfate, although compounds, comport themselves in their combinations like electronegative elements, so they are names in the same way as the oxides.
When several chlorides of the same metal exist, they are distinguished by the same numerical prefixes as oxides. Thus, we have tin oxide and dioxide. The compounds of sulfur resemble oxides, but they have generally been name sulfates and sulfides. Berzelius applies the term sulfate to binary compounds of sulfur only as are basic and correspond with basic oxides. Hence, he has potassium sulfate, arsenic sulfide, and carbon disulfide. Compounds of chlorine are distinguished by Berzelius into chlorites and chlorides based on the same principle; so, the names are potassium chloride and phosphorus chloride. These distinctions haven’t served any important purpose besides adding specificity to a compound through the addition of the “ide” ending.
The combinations of metal elements among themselves are distinguished by the name alloy, and those made of mercury, amalgams.
(b) The binary compounds of oxygen which possess acid properties are named differently. For example, the acid compound of titanium and oxygen is called titanic acid. The ending “ic” is added to the metal. Where the same element was known to form two acid compounds with oxygen, the ending “ous” was applied to the compound that contains the least amount of oxygen like sulfurous in sulfuric acid. Based on the discovery of a sulfur acid compound that contained less oxygen than the already named sulfurous acid, it was given the name hyposulfurous acid, and another compound that is the intermediate of these two compounds was given the name hyposulfuric acid. On the same principle, an acid that contains more oxygen than in chloric acid was named hyperchloric acid, with the general name of perchloric acid. Here are the names of sulfur compounds depending on the concentration of oxygen:
Names……………….Sulfur Conc……….Oxygen Conc.
Hyposulfurous acid……...100………………….50
Sulfurous acid……………100…………………100
Hyposulfuric acid………..100………………….125
Sulfuric acid……………..100………………….150
The same system is adopted for all analogous acids. An acid of chlorine, containing more oxygen than chloric acid, is named perchloric acid, and other similar compounds that all contain large amounts of oxygen, are distinguished in the same manner, for example periodic acid and permanganic acid. Perchloric acid is also called oxychloride; but this name is not as suitable as the first.
Another class of acids exists in which sulfur is united with another element in place of oxygen. The acids formed are called sulfur acids. The names of the corresponding oxygen acids are sometimes applied to these, with the prefix “sulf” such as sulfarsenic acids, which resemble arsenic acids respectively in composition, but have sulfur in place of oxygen.
Lastly, certain substances such as chlorine, sulfur, and cyanogen, form acids with hydrogen. These are called hydrogen acids or hydracids. In these acid compounds the names of both constituents are used, as seen in hydrochloric acid, hydrosulfuric acid, and hydrocyanic acid.
2.- Compounds of the second order, or salts, are named according to the acid they contain, the ending “ic” of the acid being changed to “ate”, and “ous” into “ite”. Therefore, a salt of sulfuric acid is a sulfate, and a salt of sulfurous acid is a sulfite. The name of the oxide indicates the species – as sulfate is the oxide of silver. For the oxide of the metal being always understood, it isn’t necessary to express it, unless more than one oxide of the same metal combines with acids, for example sulfate of protoxide of iron and sulfate of sesquioxide of iron. These salts are often called protosulfate and persulfate of iron, where the prefixes proto and per refer to the degree of oxidation of iron. The two oxides of iron are named iron(II) oxide and iron(III) oxide by Berzelius, and the salts referred to are ferrous sulfate and ferric sulfate. The names tin(II) sulfate and tin bisulfate express in the same way the sulfate of the protoxide of tin and the sulfate of the peroxide of tin. But such names, although truly systematic, and replacing very cumbrous expressions, involve too great a change in chemical nomenclature to be adopted quickly. Having found its way in common language, chemical nomenclature cannot be altered greatly without causing large amounts of inconvenience. It must be learned as a language, and not be treated as the expression of a system. A super-sulfate contains a greater amount of acid than the sulfate or neutral sulfate. A bi-sulfate twice as much sulfate, sesqui-sulfate meaning one and a half as much as the neutral sulfate, and sub-sulfate meaning it contains less than the neutral salt. The prefixes referring in all cases to the proportion of acid in the salt, or to the electronegative part. The excess of base in sub-salts is indicated by Greek prefixes expressive of quantity, such as di-chromate of lead, but this deviation is destined to lead to confusion. If a precise expression for these subsalts were required, it would be better to say the bibasic subchromate of lead. But the names of both acid and basic salts are less in accordance with correct view of their composition than the names of any other class of compounds.
Combinations of water with other oxides are called hydroxides: as potassium hydroxide.
3.- In the names of quaternary compounds or of double salts, the names of the constituent salts are expressed. Potassium alum sulfate is the compound of aluminum sulfate and potassium sulfate, the name of the acid only expressed once because it is the same in both constituent salts. The name alum, which has been assigned by common usage to the same double salt, is likewise received in scientific language. Platinum potassium chloride, expresses, in the same way, a compound of platinum chloride and potassium chloride.
An oxychloride, such as mercury(II) chloride, is a compound of an oxide with the chloride of the same metal.
The first ideas of a chemical nomenclature are from Guyton de Morvean, whose views were published in 1782. But, the chief merit of the construction of the valuable system in use is justly assigned to Lavoisier, who reported to the French Academy on the subject in1787. It has not been materially modified or expanded sine its first publication. The present, or Lavoisierian nomenclature, does not furnish precise expressions for many new classes of compounds, the existence of which was not contemplated by its inventors. Many of its names express theoretical views of the construction of bodies are doubtful, and not admitted by all chemists. But its deficiencies are supplied, and the composition of bodies more accurately represented in certain written expressions (chemical formula), which are also employed to denote their particular substances. These formulas are constructed on the simplest principles, and besides supplying the deficiencies of the nomenclature, they exhibit to the eye the composition of the bodies. This allows for a mechanical aid in observing relations in composition of the same kind as the use of figures in the comparison of arithmetical sums.
Symbols of the elements – Each elementary substance is represented by the initial letter of its Latin name, as it will be seen by reference to the table of elementary substances. When the names of two or more elements begin with the same letter, a second character in lowercase is added for distinction. So, oxygen is represented by the letter O, the metal osmium by Os, fluorine by F, and iron (ferrum) by Fe. It is observed that lowercase letters are never significant of themselves but employed only in connection with the capital letters as distinctive adjuncts. These symbols represent certain relative quantities of the elements, the letter O representing not oxygen indefinitely, but 100 parts by weight of oxygen, and Fe representing 350 parts by weight of iron. Any other quantities of these two substances follow the proportion of these numbers: 8 parts oxygen and 28 parts of iron. It will be immediately explained that the elementary bodies combine with each other in certain proportional quantities only, which are expressed by one or the other indifferently of the two series of numbers placed against the names of the elements in the table referred to. These quantities are conveniently spoken of as the combining proportions, or the equivalents, of the elements. The symbol of itself representing one equivalent of the element, several equivalents are represented by placing cofactors in front of it. 2Fe and 3O mean two parts of iron and three parts of oxygen. Small exponents are placed below the symbol and to the right, this Fe2 and O3 are of the same value as the former expressions, but this is used when symbols are placed together in the formula of a compound. Two equivalents of an element are sometimes represented by placing a dash through, or under its symbol, but such abbreviations will not be made of use in the present work.
Formula of compounds – The collocation of symbols express combination: thus, FeO represents a compound of one part iron and one part oxygen, or the protoxide of iron. SO3 is a compound of one part sulfur and three parts oxygen, which is the equivalent of sulfuric acid. Iron sulfate, containing one of each of the preceding compounds is represented as:
FeO SO3 or
FeO + SO3 or
FeO, SO3 or
FeSO4
The plus sign (+) or the comma, being introduced in the second and third formula to indicate a distribution of the elements of the salt into its two approximate constituents, iron oxide and sulfuric acid, which is not so distinctly indicated in the first formula.
It may be often advantageous to make use of both the comma and the plus sign int eh same formula, and then it would be a beneficial practice to use them as in the following formula for iron potassium bisulfate:
FeO, SO3 + KO, SO3
in which the comma is employed to indicate the combination of the two compounds on each side of the plus sign. So FeO would be combined with SO3, KO and SO3 combine, then they combine together. This can also be written as FeKO8S2, where each element is combined together.
The small subscripts in the preceding formula only affect the symbol or letter to which they are immediately attached to. Larger figures placed before and in the same line with the symbols apply to the compound expressed by the symbols. Thus, 3SO3 means that there are three sulfuric acid compounds, 2PbO means that there are two compounds of lead oxide. The interposition of the comma or the plus sign prevents the influence of the figure extending farther, so
2PbO, CrO3 or
2PbO + CrO3,
Is two compounds of lead oxide and one compound of chromic acid. To makes the figure apply to symbols that are separated by a comma or plus sign, it is necessary to enclose all that is to be affected within brackets and place the coefficient before them. So,
2 (PbO, CrO3)
means two compounds of lead(II) chromate. The following formula of two double salts with their water crystallization, exhibit the application of these rules:
Iron-alum, or the sulfate of peroxide of iron and potassium:
KO, SO3 + Fe2O3, 3SO3 +24HO
Oxalate of peroxide of iron and potassium:
3(KO, C2O3) + Fe2O3, 3C2O3 + 6HO
It will be found to conduce to perspicuity, to avoid either connecting two formula of different substances not in combination by the plus sign, or allowing them to be separated by a comma, the comma and the plus sign that is between symbols is understood to unite the formula into one. It is advisable to write every complete formula apart, and in a line by itself, if possible.
The only other circumstance to be attended to in the construction of such formula is the arrangement of the symbols, which is not arbitrary. In naming a binary compound, such as iron oxide or potassium chloride, we announce the metal first, followed by the nonmetal. This stays consistent in written formula because the metal, Fe, is written before the nonmetal, O. In the formula of salts, the basic oxide is written first, not the acid. So potassium sulfate is KO, SO3, and not SO3, KO. Information respecting the constitution of a compound may often be expressed in its formula attending to this rule. Sulfuric acid of specific gravity is 1.780, containing two parts of water to one part of acid, but by giving this formula:
HO, SO3 + H2O
we express that one part only of water is combined as a base with the acid, and that the second part of water is in combination with the sulfate of water.
The above system notation is complete and sufficiently convenient for representing all binary compounds, and organic compounds, in the formula of which the ultimate elements only are expressed.
Bibliography
“Chemical Nomenclature.” 2.8 Chemical Nomenclature | Chemistry, Lumen Learning, https://courses.lumenlearning.com/suny-albany-chemistry/chapter/chemical-nomenclature/.
Hartshorn, Richard M. “Brief Guide to the Nomenclature of Inorganic Chemistry.” Brief Guide to Inorganic Nomenclature, https://iupac.qmul.ac.uk/BriefGuide/inorganic.html.
Lane, Dan, and Jay Solon. Thomas Graham, https://web.archive.org/web/20050828071813/http:/www.woodrow.org/teachers/chemistry/institutes/1992/Graham.html.