CRC Handbook of Chemistry and Physics, 86th Edition

The Elements 4-25
forms of solid nitrogen exist, with the transition from the α to
the β form taking place at –237°C. When nitrogen is heated, it
combines directly with magnesium, lithium, or calcium; when
mixed with oxygen and subjected to electric sparks, it forms
first nitric oxide (NO) and then the dioxide (NO 2 ); when heated
under pressure with a catalyst with hydrogen, ammonia is
formed (Haber process). The ammonia thus formed is of the
utmost importance as it is used in fertilizers, and it can be oxidized
to nitric acid (Ostwald process). The ammonia industryis
the largest consumer of nitrogen. Large amounts of gas
are also used by the electronics industry, which uses the gas as
a blanketing medium during production of such components
as transistors, diodes, etc. Large quantities of nitrogen are
used in annealing stainless steel and other steel mill products.
The drug industry also uses large quantities. Nitrogen is used
as a refrigerant both for the immersion freezing of food products
and for transportation of foods. Liquid nitrogen is also
used in missile work as a purge for components, insulators
for space chambers, etc., and by the oil industry to build up
great pressures in wells to force crude oil upward. Sodium and
potassium nitrates are formed by the decomposition of organic
matter with compounds of the metals present. In certain
dry areas of the world these saltpeters are found in quantity.
Ammonia, nitric acid, the nitrates, the five oxides (N 2 O, NO,
N 2 O 3 , NO 2 , and N 2 O 5 ), TNT, the cyanides, etc. are but a few
of the important compounds. Nitrogen gas prices vary from
2¢ to $2.75 per 100 ft 3 (2.83 cu. meters), depending on purity,
etc. Production of elemental nitrogen in the U.S. is more than
9 million short tons per year. Natural nitrogen contains two
isotopes, 14 N and 15 N. Ten other isotopes are known.
Nobelium — (Alfred Nobel [1833–1896], inventor of dynamite),
No; at. wt. [259]; at. no. 102; valence +2, +3. Nobelium was
unambiguously discovered and identified in April 1958 at
Berkeley by A. Ghiorso, T. Sikkeland, J. R. Walton, and G. T.
Seaborg, who used a new double-recoil technique. A heavy-ion
linear accelerator (HILAC) was used to bombard a thin target
of curium (95% 244 Cm and 4.5% 246 Cm) with 12 C ions to produce
102 254 according to the 246 Cm ( 12 C, 4n) reaction. Earlier in
1957 workers of the U.S., Britain, and Sweden announced the
discovery of an isotope of Element 102 with a 10-min half-life
at 8.5 MeV, as a result of bombarding 244 Cm with 13 C nuclei.
On the basis of this experiment the name nobelium was assigned
and accepted by the Commission on Atomic Weights
of the International Union of Pure and Applied Chemistry.
The acceptance of the name was premature, for both Russian
and American efforts now completely rule out the possibility
of any isotope of Element 102 having a half-life of 10 min in
the vicinity of 8.5 MeV. Early work in 1957 on the search for
this element, in Russia at the Kurchatov Institute, was marred
by the assignment of 8.9 ± 0.4 MeV alpha radiation with a halflife
of 2 to 40 sec, which was too indefinite to support claim
to discovery. Confirmatory experiments at Berkeley in 1966
have shown the existence of 254 102 with a 55-s half-life, 252 102
with a 2.3-s half-life, and 257 102 with a 25-s half-life. Twelve
isotopes are now recognized, one of which — 255 102 — has a
half-life of 3.1 min. In view of the discover’s traditional right
to name an element, the Berkeley group, in 1967, suggested
that the hastily given name nobelium, along with the symbol
No, be retained.
Osmium — (Gr. osme, a smell), Os; at. wt. 190.23(3); at. no. 76;
m.p. 3033°C; b.p. 5012°C; sp. gr. 22.57; valence 0 to +8, more
usually +3, +4, +6, and +8. Discovered in 1803 by Tennant in
the residue left when crude platinum is dissolved by aqua regia.
Osmium occurs in iridosmine and in platinum-bearing
river sands of the Urals, North America, and South America.
It is also found in the nickel-bearing ores of Sudbury, Ontario,
region along with other platinum metals. While the quantity
of platinum metals in these ores is very small, the large tonnages
of nickel ores processed make commercial recovery
possible. The metal is lustrous, bluish white, extremely hard,
and brittle even at high temperatures. It has the highest melting
point and the lowest vapor pressure of the platinum group.
The metal is very difficult to fabricate, but the powder can
be sintered in a hydrogen atmosphere at a temperature of
2000°C. The solid metal is not affected by air at room temperature,
but the powdered or spongy metal slowly gives off
osmium tetroxide, which is a powerful oxidizing agent and has
a strong smell. The tetroxide is highly toxic, and boils at 130°C
(760 mm). Concentrations in air as low as 10 –7 g/m 3 can cause
lung congestion, skin damage, or eye damage. The tetroxide
has been used to detect fingerprints and to stain fatty tissue
for microscope slides. The metal is almost entirely used to
produce very hard alloys, with other metals of the platinum
group, for fountain pen tips, instrument pivots, phonograph
needles, and electrical contacts. The price of 99.9% pure osmium
powder — the form usually supplied commercially — is
about $100/g, depending on quantity and supplier. Natural
osmium contains seven isotopes, one of which, 186 Os, is radioactive
with a very long half-life. Thirty four other isotopes
and isomers are known, all of which are radioactive.The measured
densities of iridium and osmium seem to indicate that
osmium is slightly more dense than iridium, so osmium has
generally been credited with being the heaviest known element.
Calculations of the density from the space lattice, which
may be more reliable for these elements than actual measurements,
however, give a density of 22.65 for iridium compared
to 22.61 for osmium. At present, therefore, we know either
iridium or osmium is the heaviest element, but the data do not
allow selection between the two.
Oxygen — (Gr. oxys, sharp, acid, and genes, forming; acid former),
O; at. wt. 15.9994(3); at. no. 8; t.p. –218.79°C; t c –118.56°C; valence
2. For many centuries, workers occasionally realized air
was composed of more than one component. The behavior of
oxygen and nitrogen as components of air led to the advancement
of the phlogiston theory of combustion, which captured
the minds of chemists for a century. Oxygen was prepared by
several workers, including Bayen and Borch, but they did not
know how to collect it, did not study its properties, and did not
recognize it as an elementary substance. Priestley is generally
credited with its discovery, although Scheele also discovered
it independently. Oxygen is the third most abundant element
found in the sun, and it plays a part in the carbon-nitrogen
cycle, one process thought to give the sun and stars their energy.
Oxygen under excited conditions is responsible for the
bright red and yellow-green colors of the aurora. Oxygen, as
a gaseous element, forms 21% of the atmosphere by volume
from which it can be obtained by liquefaction and fractional
distillation. The atmosphere of Mars contains about 0.15%
oxygen. The element and its compounds make up 49.2%, by
weight, of the earth’s crust. About two thirds of the human
body and nine tenths of water is oxygen. In the laboratory it
can be prepared by the electrolysis of water or by heating potassium
chlorate with manganese dioxide as a catalyst. The gas
is colorless, odorless, and tasteless. The liquid and solid forms
are a pale blue color and are strongly paramagnetic. Ozone