IUPAC Name: 1-butylsulfanylbutane
Synonyms: 1,1'-Thiobis(butane) ; 4-01-00-01559 (Beilstein Handbook Reference) ; 5-Thianonane ; AI3-18788 ; BRN 1732829 ; Butane, 1,1'-thiobis-Butyl monosulfide ; Butylthiobutane ; Di-n-butylsulfide ; Dibutyl sulfide ; Dibutyl sulphide ; Dibutyl thioether ; EINECS 208-870-5 ; FEMA No. 2215 ; NSC 8460 ; Thiononane-5 ; n-Butyl sulfide ; n-Butyl-sulfide ; n-Dibutyl sulfide 
Systematic Name: Butane, 1,1'-thiobis- ; Butyl sulfide ; Dibutyl sulphide 
Canonical SMILES: CCCCSCCCC
InChI: InChI=1S/C8H18S/c1-3-5-7-9-8-6-4-2/h3-8H2,1-2H3
InChIKey: HTIRHQRTDBPHNZ-UHFFFAOYSA-N
Molecular Formula: C₈H₁₈S 
Molecular Weight: 146.29
EINECS: 208-870-5
Density: 0.838 g/mL at 25 °C(lit.)
Melting Point: −76 °C(lit.)
Flash Point: 170 °F
Boiling Point: 188-189 °C(lit.)
Vapor density: 5.07 (vs air)
Vapor pressure: 5.17 mm Hg ( 37.7 °C)
Refractive Index: n20/D 1.452(lit.) 
Merck 14,1590
BRN 1732829
Stability: Stable. Combustible. Incompatible with strong oxidizing agents.
Product Categories: sulfide Flavor
Following is the molecular structure of Dibutyl sulfide (CAS NO.554-40-1) is:

Safty information about Dibutyl sulfide (CAS NO.554-40-1) is:
Hazard Codes:
Xi
Risk Statements:
R36/37/38:Irritating to eyes, respiratory system and skin.
Safety Statements:
S26: In case of contact with eyes, rinse immediately with plenty of water and seek medical advice. 
S36/37/39:Wear suitable protective clothing, gloves and eye/face protection. 
S24/25:Avoid contact with skin and eyes.
RIDADR: 2810
WGK Germany: 2
RTECS: ER6417000
HazardClass: 6.1(b)
PackingGroup: III
HS Code: 29309070

 Dibutyl sulfide (CAS NO.554-40-1) is a colourless liquid with a very unpleasant smell.
First Aid Measures:
Ingestion: Do not induce vomiting. If victim is conscious and alert, give 2-4 cupfuls of milk or water. Never give anything by mouth to an unconscious person. Get medical aid.
Inhalation: Remove from exposure to fresh air immediately. If not breathing, give artificial respiration. If breathing is difficult, give oxygen. Get medical aid if cough or other symptoms appear.
Skin: Immediately flush skin with plenty of soap and water for at least 15 minutes while removing contaminated clothing and shoes. Get medical aid if irritation develops or persists.
Eyes: Immediately flush eyes with plenty of water for at least 15 minutes, occasionally lifting the upper and lower eyelids. Get medical aid.
Handling and Storage:
Storage: Keep away from sources of ignition. Store in a cool, dry place. Store in a tightly closed container.
Handling: Wash thoroughly after handling. Wash hands before eating. Use only in a well ventilated area. Avoid breathing dust, vapor, mist, or gas. Do not get on skin or in eyes. Avoid ingestion and inhalation.