Molecule
- Name
- Diacetylene
- IUPAC name
- Buta-1,3-diyne
- Secondary names
- Butadiyne, 1,3-Butadiyne, Biacetylene, C4H2
- InChI
- InChI=1S/C4H2/c1-3-4-2/h1-2H
- InChI key
- LLCSWKVOHICRDD-UHFFFAOYSA-N
- CAS number
- 460-12-8
- Comments
- natural $C_4H_2$
- Formula
- $C_4H_2$
- Chemical formula
- C4H2
- Structural formula
- [HC]#CC#[CH]
- Charge
- 0
- Unpaired electrons
- 0
- Relations
-
- no
- Isotope mixture type
- terrestrial abundance
- Spin type
- unique
- Molar mass
- 50.06 $g/mol$
- State STP
- gas
- State NTP
- gas
- Protic
- protic
- Polarity
- nonpolar
- Dipole
- 0.0 $D$
- Molecule symmetry
- Dinfh
- Case
- linear-polyatomic
- Vibrations number
- 9
- Vibrations
-
Label Mode Bond Symmetry Degeneracy Fundamental frequency Observed frequency Observed frequency Harmonic frequency Activity IR Activity Raman Strength Comments V4 stretching asym. $\equiv C-H$ $\Sigma+$ no 3332.8 active inactive vs V1 stretching sym. $\equiv C-H$ $\Sigma+$ no 3293.0 inactive active ia Raman: vw, in liquid V2 stretching sym. $-C\equiv C-$ $\Sigma+$ no 2184.0 inactive active ia Raman: vs V5 stretching asym. $-C\equiv C-$ $\Sigma+$ no 2019.8 active inactive m V3 stretching $\equiv C-C \equiv$ $\Sigma+$ no 874.0 inactive active ia Raman: w V8 bending out-p $-C \equiv C-H$ $\Pi$ double 628.0 active inactive vs V6 bending sym. $-C \equiv C-H$ $\Pi$ double 627.0 inactive active ia Raman: m V7 bending sym. $-C\equiv C-C\equiv$ $\Pi$ double 482.0 inactive active ia Raman: s V9 bending out-p $-C\equiv C-C\equiv$ $\Pi$ double 220.1 active inactive s - Comments
- Vibrations of the main isotope: $^{12}C_4~^1H_2$. IR data from Jolly et al. 2014