[U.S. Government Printing Office Style Manual]
[Chapter 10 - Signs and symbols]
[From the U.S. Government Publishing Office, www.gpo.gov]
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10. SIGNS AND SYMBOLS
10.1. The increased use of signs and symbols and their
importance in technical and scientific work have emphasized the
necessity of standardization on a national basis and of the
consistent use of the standard forms.
10.2. Certain symbols are standardized--number symbols (the
digits, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9); letter symbols (the
letters of the alphabet, a, b, c, d, etc.); and graphic symbols
(the mathematical signs +, -, , x , ).
10.3. The signs +, -, , x , and , etc.,
are closed against accompanying figures and symbols. When the
x is used to indicate ``crossed with'' (in plant or animal
breeding) or magnification, it will be separated from the
accompanying words by a space.
i-vii+1-288 pages
The equation A+B
The result is 4 x 4
20,0005,000
Early June x Bright (crossed with)
x 4 (magnification)
Symbols with figures
10.4. In technical publications the degree mark is used in
lieu of the word degree following a figure denoting
measurement.
10.5. Following a figure, the spelled form is preferred. The
percent symbol is used in areas where space will not allow the
word percent to be used.
In that period the price rose 12, 15, and 19 percent.
not In that period the price rose 12 percent, 15 percent, and
19 percent.
10.6. Any symbol set close up to figures, such as the degree
mark, dollar mark, or cent mark, is used before or after each
figure in a group or series.
$5 to $8 price range
5'-7' long, not 5-7' long
3 cents to 5 cents (no spaces)
2 to 7; 2 deg.1 deg.
but
Sec. 12 (thin space)
from 15 to 25 percent
45 to 65 deg.F not 45 deg. to 65 deg. F
Letter symbols
10.7. Letter symbols are set in italic (see rule 10.8) or in
roman (see rule 9.56) without periods and are capitalized only
if so shown in copy, since the capitalized form may have an
entirely different meaning.
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Equations
10.8. In mathematical equations, use italic for all letter
symbols--capitals, lowercase, small capitals, and superiors and
inferiors (exponents and subscripts); use roman for figures,
including superiors and inferiors.
10.9. If an equation or a mathematical expression needs to be
divided, break before +, -, =, etc. However, the equal sign is
to clear on the left of other beginning mathematical signs.
10.10. A short equation in text should not be broken at the
end of a line. Space out the line so that the equation will
begin on the next line; or better, center the equation on a
line by itself.
10.11. An equation too long for one line is set flush left,
the second half of the equation is set flush right, and the two
parts are balanced as nearly as possible.
10.12. Two or more equations in a series are aligned on the
equal signs and centered on the longest equation in the group.
10.13. Connecting words of explanation, such as hence,
therefore, and similarly, are set flush left either on the same
line with the equation or on a separate line.
10.14. Parentheses, braces, brackets, integral signs, and
summation signs should be of the same height as the
mathematical expressions they include.
10.15. Inferiors precede superiors if they appear together;
but if either inferior or superior is too long, the two are
aligned on the left.
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Chemical symbols
10.16. The names and symbols listed below are approved by the
International Union of Pure and Applied Chemistry. They are set
in roman without periods.
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Atomic Atomic
Element Symbol Atomic Element Symbol Atomic
number weight\1\ number weight\1\
----------------------------------------------------------------------------------------------------------------
Actinium....................... Ac 89 227.0278 Mercury........... Hg 80 200.59
Aluminum....................... Al 13 26.98154 Molybdenum........ Mo 42 95.94
Americium...................... Am 95 (243) Neodymium......... Nd 60 144.24
Antimony....................... Sb 51 121.75 Neon.............. Ne 10 20.179
Argon.......................... Ar 18 39.948 Neptunium......... Np 93 237.0482
Arsenic........................ As 33 74.9216 Nickel............ Ni 28 58.69
Astatine....................... At 85 (210) Niobium........... Nb 41 92.9064
Barium......................... Ba 56 137.33 Nitrogen.......... N 7 14.0067
Berkelium...................... Bk 97 (247) Nobelium.......... No 102 (259)
Beryllium...................... Be 4 9.01218 Osmium............ Os 76 190.2
Bismuth........................ Bi 83 208.9804 Oxygen............ O 8 15.9994
Bohrium........................ Bh 107 (262.0) Palladium......... Pd 46 106.42
Boron.......................... B 5 10.81 Phosphorus........ P 15 30.97376
Bromine........................ Br 35 79.904 Platinum.......... Pt 78 195.08
Cadmium........................ Cd 48 112.41 Plutonium......... Pu 94 (244)
Calcium........................ Ca 20 40.08 Polonium.......... Po 84 (209)
Californium.................... Cf 98 (251) Potassium......... K 19 39.0983
Carbon......................... C 6 12.011 Praseodymium...... Pr 59 140.9077
Cerium......................... Ce 58 140.12 Promethium........ Pm 61 (145)
Cesium......................... Cs 55 132.9054 Protactinium...... Pa 91 231.0359
Chlorine....................... Cl 17 35.453 Radium............ Ra 88 226.0254
Chromium....................... Cr 24 51.996 Radon............. Rn 86 (222)
Cobalt......................... Co 27 58.9332 Rhenium........... Re 75 186.207
Copper......................... Cu 29 63.546 Rhodium........... Rh 45 102.9055
Curium......................... Cm 96 (247) Rubidium.......... Rb 37 85.4678
Dubnium........................ Db 105 (262.0) Ruthenium......... Ru 44 101.07
Dysprosium..................... Dy 66 162.50 Rutherfordium..... Rf 104 (261.0)
Einsteinium.................... Es 99 (252) Samarium.......... Sm 62 150.36
Erbium......................... Er 68 167.26 Scandium.......... Sc 21 44.9559
Europium....................... Eu 63 151.96 Seaborgium........ Sg 106 (263.0)
Fermium........................ Fm 100 (257) Selenium.......... Se 34 78.96
Fluorine....................... F 9 18.998403 Silicon........... Si 14 28.0855
Francium....................... Fr 87 (223) Silver............ Ag 47 107.8682
Gadolinium..................... Gd 64 157.25 Sodium............ Na 11 22.98977
Gallium........................ Ga 31 69.72 Strontium......... Sr 38 87.62
Germanium...................... Ge 32 72.59 Sulfur............ S 16 32.06
Gold........................... Au 79 196.9665 Tantalum.......... Ta 73 180.9479
Hafnium........................ Hf 72 178.49 Technetium........ Tc 43 (98)
Hassium........................ Hs 108 (265.0) Tellurium......... Te 52 127.60
Helium......................... He 2 4.00260 Terbium........... Tb 65 158.9254
Holmium........................ Ho 67 164.9304 Thallium.......... Tl 81 204.383
Hydrogen....................... H 1 1.00794 Thorium........... Th 90 232.0381
Indium......................... In 49 114.82 Thulium........... Tm 69 168.9342
Iodine......................... I 53 126.9045 Tin............... Sn 50 118.69
Iridium........................ Ir 77 192.22 Titanium.......... Ti 22 47.88
Iron........................... Fe 26 55.847 Tungsten.......... W 74 183.85
Krypton........................ Kr 36 83.80 Ununnilium........ Uun 110 (269.0)
Lanthanum...................... La 57 138.9055 Unununium......... Uuu 111 (272.0)
Lawrencium..................... Lr 103 (260) Ununbium.......... Uub 112 (277.0)
Lead........................... Pb 82 207.2 Uranium........... U 92 238.0289
Lithium........................ Li 3 6.941 Vanadium.......... V 23 50.9415
Lutetium....................... Lu 71 174.967 Xenon............. Xe 54 131.29
Magnesium...................... Mg 12 24.305 Ytterbium......... Yb 70 173.04
Manganese...................... Mn 25 54.9380 Yttrium........... Y 39 88.9059
Meitnerium..................... Mt 109 (266.0) Zinc.............. Zn 30 65.38
Mendelevium.................... Md 101 (258) Zirconium......... Zr 40 91.22
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\1\The atomic weights of many elements are not invariant but depend on the origin and treatment of the material.
The values of atomic weight given here apply to elements as they exist naturally on Earth and to certain
artificial elements. Values in parentheses are used for radioactive elements whose atomic weights cannot be
quoted precisely without knowledge of the origin of the elements. The value given is the atomic mass number of
the isotope of that element of longest known half life.
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Standardized symbols
10.17. Symbols duly standardized by any national scientific,
professional, or technical group are accepted as preferred
forms within the field of the group. The issuing office
desiring or requiring the use of such standardized symbols
should see that copy is prepared accordingly.
Signs and symbols
10.18. The following list contains some signs and symbols
frequently used in printing. The forms and style of many
symbols vary with the method of reproduction employed. It is
important that editors and writers clearly identify signs and
symbols when they appear within a manuscript.
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