6.11 Mathematical, statistical and scientific material

Italicize the scientific (Latin) names of genera and species in botanical, zoological and paleontological matter:

  • The sugar maple (Acer saccharum) is a member of the family Aceraceae.

Do not italicize the names of the larger subdivisions (phyla, classes, orders, families and tribes):

  • The order Primates includes modern man (Homo sapiens).

Italicize letters designating unknown quantities and constants, lines, etc. in algebraic, geometric and similar matter:

  • Let n be the number of molecules . . .
  • 5x × a2 – 2ab

Note in the second example that no space is left between the numerical coefficients and the variables, and that the italics help to differentiate between the variable x and the multiplication sign. Correct spacing and italic type also help to distinguish between algebraic variables and SI/metric symbols:

  • 10x m
  • 6a cm
  • 10b L

Italicize quantity symbols such as l for length, m for mass and v for velocity in order to distinguish them from unit symbols such as "L" for litre, "m" for metre and "V" for volt, which are normally printed in roman type:

  • 60 N = m × 12m/s2
  •  m = 5 kg
  • (N = newton, m = mass, and m = metre)

Italicize Latin prefixes and Greek and Roman letters used as prefixes to the names of chemical and biochemical compounds:

  • cis-dimethylethylene
  • ß-lactose
  • N-acylneuraminic acid
  • M-xylene

A number of Greek and Roman letters used in statistical formulas and notations are italicized:

  • P
    • probability of
  • µ
    • population mean
  • Ó
    • population standard deviation
  • Ó2
    • population variance