48695528 the-sulphur-system

1. The Sulphur System
Presented By
Hitesh Wagle

2. The Sulphur System
•Sulphur can exists in four possible phases:
oTwo solid polymorphic phases
Rhombic Sulphur (SR) (m.p. 114°C)
Monoclinic Sulphur (SM) (m.p. 120°C)
oSulphur Liquid
oSulphur Vapours

3. Components & Phase Rule
•All the four phases can be represented by the
only chemical individual “SULPHUR” itself.
•Hence an one component system.
•Phase rule (F= C-P+2) becomes:
F= 3-P

4. Phase Diagram
of
Sulphur System

5. Solid
Rhombic
(SR)
Liquid (L)
Vapour (V)
1 atm
A
B
C
D
E
G
F
Solid
Monoclinic
(SM)
95.6
P
r
e
s
s
u
r
e
(
a
t
m
)
Temperature °C
114 120 444.6
B.P.
SR/V
SM/V
L/V
S
M
/L
S
R/S
M
SR/L
1290 atm
165

6. Curves In Phase Diagram
•Curve AB: Sublimation Curve of Rhombic Sulphur
•Curve BC: Sublimation Curve of Monoclinic Sulphur
• Curve CD: Vapour Pressure Curve of Liquid Sulphur
•Curve CE: Fusion Curve of Monoclinic Sulphur
•Curve BE: Transition Curve Solid Sulphur
•Curve EG: Fusion Curve of Rhombic Sulphur
•At any curve, phase rule becomes,
F= 3-P = 3-2 = 1 (Monovarient)

7. Curve AB: Sublimation Curve of Rhombic Sulphur

8. Curve BC: Sublimation Curve of Monoclinic Sulphur

9. Curve CD: Vapour Pressure Curve of Liquid Sulphur

10. Curve CE: Fusion Curve of Monoclinic Sulphur

11. Curve BE: Transition Curve of Solid Sulphur

12. Curve EG: Fusion Curve of Rhombic Sulphur

13. Triple Points
•Triple Point B
•Triple Point C
•Triple Point E
•At any Triple Point,
phase rule
becomes:
F = 3-P = 3-3 = 0
(nonvarient)

14. Areas in Phase Diagram
•Area ABEG (Rhombic Sulphur)
•Area BCEB (Monoclinic Sulphur)
•Area DCEG (Sulphur Liquid)
•Area ABCD (Sulphur Vapours)
•In an area, Phase Rule becomes:
F = 3-P= 3-1 = 2
(bivariant)

15. Metastable Equilibrium
•3 Dashed curve:
curve BF (sublimation curve of metastable SR)
curve CF (vapour press. Curve of supercooled liquid
sulphur)
curve FE (fusion curve of metastable SR)
•One triple point F
•3 areas:
Area ABFE (Metastable SR)
Area ABFCD (Sulphur vapours)
Area DCFE (supercooled liquid sulphur)

16. Thank
You