[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. [GRAPHIC(S) NOT AVAILABLE IN TIFF FORMAT]