[U.S. Government Printing Office Style Manual]
[Chapter 10 - Signs and Symbols]
[From the U.S. Government Publishing Office, www.gpo.gov]
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 Early June x Bright (crossed with)
The equation A+B x 4 (magnification)
The result is 4x4 miles � gallons
20,000�5,000
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,
number mark, dollar mark, or cent mark, is used before or after
each figure in a group or series.
$5 to $8 price range but
5'-7' long, not 5-7' long 12 (thin space)
3 to 5 (no spaces) 1951 (thin space)
�2 to �7; 2��1� from 15 to 25 percent
#61 to #64 45 to 65 F not 45 to
65 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.
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 fl ush 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 fl ush 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.
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.
Element Symbol Atomic Element Symbol Atomic
No. No.
Actinium............. Ac 89 Mendelevium...... Md 101
Aluminum............. Al 13 Mercury.......... Hg 80
Americium............ Am 95 Molybdenum....... Mo 42
Antimony............. Sb 51 Neodymium........ Nd 60
Argon................ Ar 18 Neon............. Ne 10
Arsenic.............. As 33 Neptunium........ Np 93
Astatine............. At 85 Nickel........... Ni 28
Barium............... Ba 56 Niobium.......... Nb 41
Berkelium............ Bk 97 Nitrogen......... N 7
Beryllium............ Be 4 Nobelium......... No 102
Bismuth.............. Bi 83 Osmium........... Os 76
Bohrium.............. Bh 107 Oxygen........... O 8
Boron................ B 5 Palladium........ Pd 46
Bromine.............. Br 35 Phosphorus....... P 15
Cadmium.............. Cd 48 Platinum......... Pt 78
Calcium.............. Ca 20 Plutonium........ Pu 94
Californium.......... Cf 98 Polonium......... Po 84
Carbon............... C 6 Potassium........ K 19
Cerium............... Ce 58 Praseodymium..... Pr 59
Cesium............... Cs 55 Promethium....... Pm 61
Chlorine............. Cl 17 Protactinium..... Pa 91
Chromium............. Cr 24 Radium........... Ra 88
Cobalt............... Co 27 Radon............ Rn 86
Copper............... Cu 29 Rhenium.......... Re 75
Curium............... Cm 96 Rhodium.......... Rh 45
Darmstadtium......... Ds 110 Roentgenium...... Rg 111
Dubnium.............. Db 105 Rubidium......... Rb 37
Dysprosium........... Dy 66 Ruthenium........ Ru 44
Einsteinium.......... Es 99 Rutherfordium.... Rf 104
Erbium............... Er 68 Samarium......... Sm 62
Europium............. Eu 63 Scandium......... Sc 21
Fermium.............. Fm 100 Seaborgium....... Sg 106
Fluorine............. F 9 Selenium......... Se 34
Francium............. Fr 87 Silicon.......... Si 14
Gadolinium........... Gd 64 Silver........... Ag 47
Gallium.............. Ga 31 Sodium........... Na 11
Germanium............ Ge 32 Strontium........ Sr 38
Gold................. Au 79 Sulfur........... S 16
Hafnium.............. Hf 72 Tantalum......... Ta 73
Hassium.............. Hs 108 Technetium....... Tc 43
Helium............... He 2 Tellurium........ Te 52
Holmium.............. Ho 67 Terbium.......... Tb 65
Hydrogen............. H 1 Thallium......... Tl 81
Indium............... In 49 Thorium.......... Th 90
Iodine............... I 53 Thulium.......... Tm 69
Iridium.............. Ir 77 Tin.............. Sn 50
Iron................. Fe 26 Titanium......... Ti 22
Krypton.............. Kr 36 Tungsten......... W 74
Lanthanum............ La 57 Uranium.......... U 92
Lawrencium........... Lr 103 Vanadium......... V 23
Lead................. Pb 82 Xenon............ Xe 54
Lithium.............. Li 3 Ytterbium........ Yb 70
Lutetium............. Lu 71 Yttrium.......... Y 39
Magnesium............ Mg 12 Zinc............. Zn 30
Manganese............ Mn 25 Zirconium........ Zr 40
Meitnerium........... Mt 109
Standardized symbols
10.17. Symbols duly standardized by any national scientifi c,
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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