2) The lower number of the two carbon atoms of the triple bond is used to
designate the location of the triple bond.
3) Where there is a choice the double bond is given the lower number.
H CCH CH^3 CH^2 C CCH^3 H C CCH^2 CH CH^2
Ethyne or acetylene 2-Pentyne 1-Penten-4-yne
32 1
ClH 2 CC CH
4321
H 3 CC CCH 2 Cl HC CCH 2 CH 2 OH
4 32 1
3-Chloropropyne 1-Chloro-2-butyne 3-Butyn-1-ol
CH 3 CHCH 2 CH 2 C CH
CH 3
654321
CH 3 CCH 2 CCH
CH 3
CH 3
5 4 321
CH 3 CCH 2 C CH
OH
CH 3
1 2 3 4 5
5-Methyl-1-hexyne 4,4-Dimethyl-1-pentyne 2-Methyl-4-pentyn-2-ol
- Terminal alkynes:
R CCH
A terminal alkyne
Acetylenic dydrogen
1) Alkynide ion (acetylide ion):
R CC
−
CH^3 CC
−
An alkynide ion (an acetylide ion) The propynide ion
4.7 PHYSICAL PROPERTIES OF ALKANES AND CYCLOALKANES
- A series of compounds, where each member differs from the next member by a
constant unit, is called a homologous series. Members of a homologous series
are called homologs.
- At room temperature (rt, 25 °C) and 1 atm pressure, the C 1 -C 4 unbranched