5/2

5/2, the just major tenth, is the ratio between the 2nd and 5th harmonics; one octave above 5/4. It comes up in open voicings of various chords involving 5/4. For example, it is the bounding interval of 4:7:10 and 14:20:35, which may be used as the fundamental consonances of the 2.5.7 subgroup.

Interval information

Ratio	5/2
Factorization	2-1 × 5
Monzo	[-1 0 1⟩
Size in cents	1586.314 ¢
Name	just major tenth
Color name	cy3, coyo 3rd
FJS name	[math]\displaystyle{ \text{M10}^{5} }[/math]
Tenney norm (log2 nd)	3.32193
Weil norm (log2 max(n, d))	4.64386
Wilson norm (sopfr(nd))	7
[sound info]
Open this interval in xen-calc

In 2026, CompactStar proposed the name sestertave for this interval in the context of using it an equivalence. This is derived by the same logic as "tritave", using a somewhat obscure Latin-based numerical prefix for 5/2, sester-, which literally means "half-three" (as in halfway to three if you start at two), found in words like "sestercentennial".

See also

• Ed5/2.