Henry Leffmann.

A compend of chemistry, inorganic and organic including urinary analysis online

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to two-thirds their weight of calcium phosphate. The bones are burned, and
from the bone ash the phosphorus is obtained.

Phosphorus is usually seen in colorless, almost transparent sticks, soft as
wax; when kept for some time, especially in the light, it becomes brown-
ish, opaque, and harder. It is kept under water. It takes fire easily, and
burns with a bright flame, producing white clouds of phosphoric anhydrid,
P 2 5 . Exposed to air at low temperature, it can still undergo a slow combus-
tion, producing P 2 O s ; it is then luminous in the dark. It is insoluble in
water, but dissolves in oils and in carbon disulfid. It is extremely poison-
ous, death having occurred from less than }£ grain. Phosphorus melts at
111° F. (43 C), and boils at 550 F. (288 C). By keeping it at a tempera-
ture of 450 F. (232 C.) for some hours, in a closed vessel, phosphorus is

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converted into the amorphous or red phosphorus, an allotropic form, which is
red, insoluble in carbon disulfid, difficult to burn, non -poisonous, and shows
many other minor differences. Its composition is the same. This change is also
produced by adding a small quantity of iodin to common phosphorus. The
uses of the element in matches and as a medicinal substance are well known.

In all experiments with it great care must be taken, as it is easily inflamed
and produces one of the most severe forms of burns known. It should be
handled with a pair of forceps, and cut or divided only under water;

Phosphorus acts as a triad or pentad ; its affinities in the free state are very
high. It is a powerful reducing agent. In very minute quantity it is detected
by its luminosity when distilled in a dark room.

Hydrogen Phosphid, PH 2 , Phosphin. — This body is formed under conditions
analogous to those which produce amin. When a solution of sodium hydroxid
is boiled with phosphorus, hydrogen" phosphid is formed.

The reaction is —

3 NaHO + 3 H 2 + ^4= 3NaH 2 P0 2 + PH 8 .

NaH 2 P0 2 is sodium hypophosphite. Hydrogen phosphid is a colorless gas
of a disagreeable odor. As ordinarily made it is spontaneously inflammable,
but this is due to the presence of a small quantity of the vapor of a liquid
phosphid, PH 2 , phosphidogen. If this latter be removed by passing the fresh
gas through a tube placed in a freezing apparatus, the power of spontaneously
inflaming is lost.

Hydrogen phosphid forms many compounds analogous to those formed by

Compounds of Phosphorus with Oxygen. — Only two compounds are defi-
nitely known. These are : —

P 2 O s .... Phosphorous anhydrid or phosphorous oxid.
P 2 6 .... Phosphoric anhydrid or phosphoric oxid.

Phosphorous Anhydrid, P 2 O s , is produced by the slow oxidation of phos-

Phosphoric Anhydrid, P 2 O s . — This is easily produced by burning phos-
phorus in the air. It is a snow-like solid, which rapidly absorbs water. It is
capable of uniting with water in at least three proportions, forming different
bodies. The combination is shown in the following equations : —

PA + H.O = 2HP0, . .

. . Metaphosphoric acid.

P,0 6 + 2H,0 = H 4 P,0, . .

. . Pyropnosphoric "

PA + 3H.O = 2H,P0 4 . .

. . Orthophosphoric "

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The third acid is the one that yields all the common phosphates.

Metaphosphoric acid is distinguished by the power of coagulating albumin.
Although the three phosphoric acids differ in oxygen, the termination " ic "
is not changed. This is because they are all formed from the same anhydrid ;
the difference in oxygen is due to the amount of water, and all contain pentad
phosphorus. The number of salts formed by each acid is in proportion to the
number of molecules of water which it has taken up.

Metaphosphoric acid, produced by adding one molecule of water, gives one
series of salts : —

NaP0 8 Sodium metaphosphate.

Ca(PO,) 2 Calcium "

Pyrophosphoric acid, produced by adding two molecules of water, gives two
series of salts, acid and normal : —

NajHjP^ Acid sodium pyrophosphate.

Na 4 P 2 7 Sodium "

Orthophosphoric acid, produced by adding three molecules of water, gives
three series of salts, di-acid, acid, and normal : —

NaH 2 P0 4 Di-acid sodium orthophosphate.

NajHPO^ Acid

NajP0 4 Sodium orthophosphate.

Sodium, potassium, and ammonium phosphates are mostly soluble in water.
Almost all others are insoluble in water, but soluble in acids.

Silver nitrate produces with orthophosphates a yellow precipitate soluble in
ammonium hydroxid. A solution of ammonium molybdate in nitric acid gives
a bright yellow precipitate. This is a very delicate test.

Two phosphorus chlorids are known, PC1 8 and PCl^.


Arsenum, As, 75, occurs in the free state and as sulfid, also in combina-
tion, especially with nickel, cobalt, and iron. It is rather abundant, and ex-
ists in small amounts in many minerals. It is often called arsenic, but
arsenum is a preferable name.

It is prepared by deoxidizing arsenous anhydrid by charcoal : —

AsA + C, = As 2 + 3CO.
When freshly prepared it is a steel-gray, brittle mass with a decided lustre.

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It tarnishes somewhat in the air, and passes into vapor at about 356 F.
(180 C.) without fusing. Heated in contact with air, it oxidizes to arsen-
ous anhydrid, and develops a garlicky odor. It is not dissolved by any
simple solvent.

Arsifty AsH 3 , Hydrogen Arsenid. — This body is analogous to amin ; its
formation is a delicate test for arsenic. The usual method of preparation is
to liberate hydrogen in a solution of arsenous anhydrid. It is a combustible
gas of disagreeable odor and very poisonous.

Compounds of Arsenum with Oxygen : —

As^g Arsenous oxid or arsenous anhydrid.

A&jOj Arsenic " " "

Arsenous Anhydrid \ AsjO,, Arsenous Oxid, White Arsenic. — This sub-
stance is often called arsenic. It presents itself in commerce in two varie-
ties : (a) The vitreous form, transparent and colorless at first, but afterward
becoming yellowish and porcelain like ; (b) A pulverulent form, which is dis-
tinctly crystalline.

Arsenous oxid is a white solid, odorless and tasteless, dissolving with diffi-
culty and only in small amounts in cold water ; the solution is feebly acid,
and is supposed to contain arsenous acid, H s AsO s . Hot water is a more
active solvent. A fluidounce of cold water will dissolve about one grain, and
the same amount of water if kept for one hour at the boiling-point will take
up at least twelve grains. In acid and alkaline solutions it dissolves much
more readily. Heated to 380 F. (190 C), the solid passes into vapor with-
out fusing, and if allowed to condense produces brilliant, transparent crystals.
It is intensely poisonous in all its forms, a few grains being a fatal dose.
Arsenous oxid is used in medicine, also in the manufacture of colors, and for
many other purposes. Its frequent occurrence and poisonous qualities have
made its properties and tests of great importance. The following is a brief
summary of the methods used : —

1. Reduction Test. — A small quantity of powdered arsenous oxid is mixed
with some dried potassium ferrocyanid and heated in a narrow glass tube.
Arsenum is set free, rises in vapor, and condenses on a cooler portion of the
tube, as a dark steel-gray but rather lustrous layer, called the arsenical
mirror. If this deposit be heated, it may be driven further along the tube,
and will finally oxidize and produce the garlicky odor.

2. Sublimation Test. — Arsenous oxid heated alone passes quickly into vapor,
and by allowing this vapor to condense upon a slightly warmed part of the
tube fine crystals are formed. Under the microscope these crystals are seen

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to be octahedral ; that is, consist of eight triangular faces, though they are
rarely completely formed. ^ Very minute quantities of arsenic can be recog-
nized by this test.

3. Reinsch's Test. — This is the most valuable test, because it can be applied
to impure mixtures, as the contents of a stomach. A small quantity of water
is put into a wide test-tube or porcelain basin ; some hydrochloric acid is
added ; a piece of clean copper is put in and the water brought to boiling. A
few drops of the suspected solution are now added, and if an arsenum com-
pound be present a dull, steel -colored deposit of copper arsenid will soon form
on the copper. When this deposit has become rather dense, the copper is
taken out, dried with filter paper, rolled up into small bulk, and placed in
the end of a small glass tube. Heat being applied, the deposit is oxidized and
volatilized, forming octahedral crystals of arsenous oxid.

4. Marsh's Test. — This depends on the power of nascent hydrogen to form
arsin, AsH 8 . The hydrogen is obtained either by the action of sulfuric acid
upon zinc or magnesium, of sodium amalgam on water, or by a current of
electricity. Arsin is combustible. If a cold porcelain plate be held in the
flame, a soot of arsenum will be deposited as a brown, shining stain. If the
tube which is conducting the current be heated, the gas will be decomposed
and a similar stain formed within the tube. The stains may be identified by
the fact that they are : (a) easily volatile ; (6) soluble in a solution of bleach-
ing powder ; (c) capable of producing octahedral crystals of arsenous oxid.

Three tests, known as the liquid tests, are applicable only to pure solutions
of arsenous oxid. They are —

1. Hydrogen sulfid produces a lemon -yellow precipitate of arsenous sulfid,

AsA -h 3H,S = AsjS, + 3H a O.

A few drops of hydrochloric acid facilitate the action.

2. Silver nitrate made feebly alkaline by ammonium hydroxid gives a
yellow precipitate of silver arsenite.

3. Copper sulfate, made feebly alkaline, gives a green precipitate of copper

Arsenic Oxid 9 As 2 6 . — This is produced by oxidizing arsenous oxid with
nitric acid. It forms with water arsenic acid, H 3 As0 4 , which is used as an
oxidizing agent in the manufacture of anilin colors'. This use has been sup-
posed to account for the cases of skin irritation which have been occasionally
observed to follow the wearing of goods dyed with these colors, but it is
doubtful if any of the poison ordinarily remains in the manufactured fabric.

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Arsenic acid forms salts called arsenates. Three forms of arsenic acid are
known, corresponding to the three forms of phosphoric acid.
Compounds of Arsenum and Sulfur. — Three of these are known : —

AsS .... Arsenum monosulfid, realgar.
As^ . . . Arsenous sulfid, orpiment.
As 2 S 5 . . . Arsenic "

Realgar is a brick-red solid, easy volatile. It may be considered as analo-
gous to NO. It is often written as AsjSj.

Orpiment, King's yellow^ is found as a mineral and is easily produced
artificially by the action of hydrogen sulfid upon arsenous compounds.

It is a bright yellow solid, fusible and volatile, soluble in alkalies, but insolu-
ble in water and dilute acids. It is often obtained in the process of testing
for arsenic, and in the arts is used as a pigment.

Arsenum forms chlorids, bromids, and iodids, but they need not be described.


Antimony, Sb, 122, occurs sometimes in the free state, but generally as
sulfid, Sb 3 S 8 . It is also called Stibium.

Antimony is bluish-white, brittle, generally highly crystalline and of bril-
liant lustre. It fuses at 842 F. (450 C), and volatilizes at a red heat. On
cooling from the melted condition it expands somewhat, and some of its alloys
retain this property, for which reason it is used in type metal and other alloys
which must take sharp casts. Like arsenum, it is not soluble in any simple

The chemical relations of antimony are much like those of arsenum, phos-
phorus, and nitrogen. It forms an oxid which is slightly basic.

Antimony is detected by tests similar to those of arsenum. The distinctive
differences are : —

1. The sublimate of free antimony cannot be obtained by the reduction
test unless a very high temperature be used.

2. Antimonous oxid cannot be volatilized except by a high heat, and does
not usually form octahedral crystals, but these have been obtained under
certain conditions.

3. The copper slip in Reinsch's test becomes covered with a bluish or
violet deposit, which gives a sublimate only with great difficulty.

4. In Marsh's test a much darker spot is obtained; it is volatilized with
difficulty, and not dissolved by a solution of bleaching powder.

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5. The liquid tests give no result, except with hydrogen sulfid, which pro-
duces an orange-red precipitate.

Stibin, Hydrogen Antimonid, SbH 8 , resembles the corresponding arsenic
compound, and is produced under similar conditions. It has not been obtained

Compounds of Antimony with Oxygen, — These are : —

Sb 2 3 ...... Antimonous oxid, or anhydrid.

Sb 8 5 Antimonic " "

An intermediate oxid, Sb 2 4 , probably a mixture of the other two, is known.

Antimonous Oxid, Sb,0 3 . — This is found as a mineral, and is also readily
prepared by burning antimony in the air. It is like AsjOj in many of its
chemical relations, but is insoluble in water, less volatile, and shows some
power of combining with acids to form salts. When boiled with a solution
of cream of tartar (acid potassium tartrate) antimonous oxid loses one atom of
oxygen, and dissolves, forming tartar emetu, potassium antimonyl tartrate.
This compound is the most familiar preparation of antimony, as it dissolves
in water without decomposition. The reaction in its production is : —

2KHC 4 H 4 O c -f- Sb 2 O s = 2K(SbO)C 4 H 4 6 + H 2 0.

The SbO replaces the hydrogen.

Boron or arsenum may take the place of antimony in this compound.

Antimonic Oxid, Sb 2 5 , forms two acids corresponding to the meta- and
pyrophosphoric acids : HSbO a , metantimonic, and H 4 Sb 2 7 , pyrantimonic
acid. Pyrantimonic acid is remarkable for forming a sodium compound in-
soluble in water.

Antimony forms compounds with chlorin, bromin and iodin analogous to
those of phosphorus and arsenic. They are mostly decomposed when mixed
with large quantities of water, yielding at first an impure, finally a pure,
oxid. With antimonous chlorid we have —

3SbCl 3 + 3H 2 = SbCl 3 Sb 2 8 -f 6HC1.

The oxychlorid, SbCl 3 Sb 2 3 , becomes finally converted into pure anti-
monous oxid.
Antimony Sulfids. — Two are known : —

Sb 2 S 3 Antimonous sulfid.

Sb 2 S 6 Antimonic sulfid.

Antimonous Sulfid is the principal ore of antimony. It is found as a shin-
ing, gray, crystalline mass, fusible and easily oxidized by heating in the air.

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Hydrochloric acid dissolves it easily, forming antimonous chlorid and hydro-
gen sulfid : —

Sb a S 8 + 6HC1 = 2SDCI3 -f 3H 3 S.

On the other hand, a current of hydrogen sulfid passed into antimony solu-
tions produces the antimonous sulfid as an orange-red precipitate, which by
heating becomes like the natural form.

Antimonic Sulfid is an orange-yellow body.

The chemical relations of antimony are well shown in its sulfids. Both of
them act as anhydrids, and form a series of salts.

KSbS 2 Potassium sulfantimonite

is strictly comparable to

KN0 2 Potassium nitrite.

Antimonic sulfid forms salts upon the pattern of the orthophosphates.

NagSbSj Sodium sulfantimonate

is analogous to

NajPC^ Sodium orthophosphate.

Sodium sulfantimonate has been used in photography under the name of
Schlippe's salt.


Bismuth, Bi, 208, is commonly found native ; also as oxid and sulfid.

It is hard, brittle, reddish-white, and distinctly crystalline. It fuses at 507
F. (264 C), expanding when it solidifies. It is not much affected by the
air. Nitric acid dissolves it.

Bismuth Sesquioxid, Bi,0 8 , the only important oxid, is obtained as a yel'
lowish powder by burning bismuth in the air or by heating the carbonate or
nitrate. It acts as a base.

Bismuth Nitrate, Bi(N0 8 ) 8 , made by dissolving bismuth in nitric acid, is a
soluble, white, crystalline mass. When added to a large volume of water, a
white precipitate of bismuth oxynitrate, of irregular composition, but gener-
ally BiN0 3 0, is thrown down. This powder, ordinarily called bismuth sub-
nitrate, is used in medicine and sometimes as a cosmetic. When it is boiled
with sodium hydroxid and a solution of glucose, a heavy black powder of free
bismuth is formed. This is Boettger's test for sugar.

Bismuth Chlorid, BiCl 3 , is decomposed by water in a manner similar to the
nitrate, producing an oxy chlorid.

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Bismuth Subcarbonate, a compound of irregular composition, is used in


Gold, Au, 196.7, occurs in the free state, often in veins in quartz, often in
small grains in sand and gravel ; sometimes alloyed with silver, copper, or
other bodies.

Pure gold is very heavy (specific gravity, 19.4), capable of being worked
into thin plates or wire, and an excellent conductor of heat and electricity.
The ordinary yellow appearance is due to much admixed white light. The
true color, red, is obtained by repeated reflections. It melts at 1900 F.
(1036 C). It is unaffected by air, water, sulfur, or ordinary acids, even
at high temperatures. Its compounds are reduced by heat, and by reducing
agents in the cold. Chlorin or a mixture of nitric and hydrochloric acid
(which contains free chlorin) dissolves it, forming a chlorid. In the pure
condition it is very soft and can be welded in the cold by pressure. Gold-
foil is prepared in this form for dentists' use. For articles subjected to wear
it is alloyed with copper or silver. The proportion of alloy is indicated by
carats, pure gold being 24 carats, 1 8 -carat gold being 18 parts gold and 6
parts alloy. Copper makes a red alloy ; silver, a green alloy. The United
States coin gold contains 90 per cent, of gold alloyed with copper and silver.
Two sets of compounds are known, aurous and auric, in which the metal is
respectively a monad and a triad. The oxids are not bases ; one appears to
be an anhydrid.

AujO . . Aurous oxid.

Au^O, . . Auric "

AuCl . . Aurous chlorid.

AuCl 8 . . Auric "

Auric Chlorid is produced when gold is dissolved in nitro- muriatic acid.
By adding to the liquid, free from excess of acid, some ferrous sulfate, the
gold is thrown down as a brown powder. A mixture of stannous and stannic
chlorids produces with gold chlorid a purple precipitate, called furple of
Cassius, used for coloring glass and porcelain.

Vanadium, V, 51.3, is a rare body, found chiefly in combination with
iron and lead. It forms four oxids. VO, V 2 3 , VO„ V 2 6 .

Vanadic Anhydrid ', V t 6 , forms salts called vanadates. Lead vanadate is
found as a mineral. It yields compounds analogous to metaphosphoric acid,

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and also forms salts with some of the strong acids. Vanadium has acquired
some importance from the possibility of making from it a good indelible ink,
but the rarity of its compounds has interfered with this use.

Carbon Group. — This includes carbon, silicon, tin, and titanium. They
are positive tetrads. With the exception of carbon and silicon they form
feebly basic oxids. All of them form acid anhydrids. Platinum may also
be placed in this group.


Carbon, C, ia, occurs very abundantly in nature. It is so constant a
component of organic bodies that organic chemistry has been called the chem-
istry of the carbon compounds. In the tissues of animals and plants it
exists in union with hydrogen, oxygen, and nitrogen. The various forms of
coal and graphite, and certain carbonates, especially of calcium and magne-
sium, are abundant minerals. Carbon presents itself under several allotropic

Amorphous Carbon , such as lampblack and charcoal.

Graphite, or Plumbago, a crystalline form.

Diamond, also crystalline, often chemically pure.

These forms are insoluble in all ordinary liquids, infusible and unacted
upon by acids and alkalies or by the air at ordinary temperatures. Heated
strongly in air or oxygen, they burn, producing CO or CO,.

Lampblack is the deposit from smoky flames. It generally contains

Wood charcoal contains hydrogen and the mineral substances of the wood.

Animal charcoal is obtained by charring animal tissues.

Wood and animal charcoals have great powers of absorption — the former
for gases, the latter for organic matters, especially colors and bitter principles.

This property of wood charcoal explains its use as a deodorizer. Gases
containing hydrogen, sulfur, or phosphorus are generally entirely decom-
posed when absorbed by charcoal.

If a solution of some organic color, such as litmus or cochineal, be filtered
through animal charcoal, the color will be partly or wholly removed. Bitter

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principles, such as strychnin or the bitter of hops, will also be removed.
Animal charcoal is extensively used for the decolorization of syrups and
vegetable infusions generally.

Graphite, called also plumbago and black lead, is destitute of any absorb-
ent properties, and is used for lead-pencils and for crucibles.

Diamond is a crystalline form of carbon. It is the hardest substance
known, and has been used with great advantage for the drilling and cutting
of stone.

The specific gravity, color, and hardness are different in the various forms
of carbon.

Coal has been formed from organic matter. Bituminous or soft coals are
first produced. They contain hydrogen and oxygen. Coke is the residue
after heating the coal. Anthracite coal is much harder, and has very little
hydrogen. It yields no gas on heating.

Carbon is a tetrad, and combines with many elements.

Compounds of Carbon with Hydrogen. — Hydrogen and carbon combine in
many proportions.

Coal Gas. — When bituminous coal is heated in a closed vessel, a large
amount of gas is given off. This gas, after being purified, constitutes illumin-
ating gas — a mixture of hydrogen, methane, CH 4 , ethene, C 2 H 4 , and other

Compounds of Carbon with Oxygen. The important ones are —

Carbon monoxid, CO.

Carbon dioxid,
Carbonic anhydrid

Carbon Monoxid, Carbonic Oxid t CO. — This is produced when carbon is
burned in a deficient supply of air, as in stoves with defective draft and in
the large furnaces for reducing and working iron, in which an excess of fuel
is purposely maintained. When steam is thrown upon hot coal a mixture of
carbon monoxid and hydrogen, generally called water-gas, is produced. This
is available as a gaseous fuel, or may be impregnated with vapors of gasoline
and used as a source of light. For experimental purposes the action of sul-
furic acid upon oxalic acid or upon potassium ferrocyanid is used for the pre-
paration of CO.

Carbon monoxid is a colorless, odorless, tasteless gas, of decidedly narcotic
poisonous properties. It is a little lighter than air. It burns easily with a
clear blue flame. It is an unsaturated molecule, and will combine with chlo-
rin and some other elements. By reason of its unsaturated condition, it has

: d ;} ...co,.

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the power to unite firmly with hemoglobin, and prevent the proper oxidation
of the blood, thus producing, when inhaled, a persistent asphyxiated condi-
tion. Poisoning by carbon monoxid has now become of common occurrence
in consequence of the extended use of water-gas. It is not unlikely that the
unnoticed escape of this gas in houses is the cause of much discomfort and ill

Carbon Dioxid y Carbonic Anhydrid, C0 2 , often wrongly called carbonic
acid, is an abundant substance occurring in air and water. Some of its com-
pounds, especially calcium and magnesium carbonates, are common minerals.
Carbon dioxid is produced in a great variety of ways : —

1. By the respiration of animals;

2. By ordinary combustion ;

3. By fermentation and decay ;

4. By decomposition of carbonates, either by heat or by acids.
The reaction in the case of chalk and hydrochloric acid is —

CaC0 8 + 2HCI = CaCl, + H a O + C0 2 .

It is unimportant whether we regard the water and C0 2 as separate or
waited to form carbonic acid, H 2 CO s . By passing the escaping gas over dry
calcium chlorid or strong sulfuric acid the pure C(\may be collected.

Properties. — Carbon dioxid is a colorless gas of a somewhat sharp taste.
It is soluble at ordinary pressure in its own bulk of water, and the solubility

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Online LibraryHenry LeffmannA compend of chemistry, inorganic and organic including urinary analysis → online text (page 7 of 20)