The Molecular Structure of DL-Malic acid (CAS NO.617-48-1):

Empirical Formula: C₄H₆O₅
Molecular Weight: 134.0874
IUPAC Name: 2-hydroxybutanedioic acid    
Appearance:  white crystalline powder 
Nominal Mass: 134 Da
Average Mass: 134.0874 Da
Monoisotopic Mass: 134.021523 Da
Index of Refraction: 1.529
Molar Refractivity: 25.2 cm³
Molar Volume: 81.6 cm³
Surface Tension: 86.2 dyne/cm
Density: 1.641 g/cm³
Flash Point: 153.4 °C
Enthalpy of Vaporization: 63.43 kJ/mol
Boiling Point: 306.4 °C at 760 mmHg
Vapour Pressure: 7.19E-05 mmHg at 25°C
Product Categories: MalicAcidSeries 
Solubility methanol: 0.1 g/mL, clear, colorless
Stability: Stable. Incompatible with strong oxidizing agents, strong bases, amines, alkali metals, carbonates
Synonyms:  (+/-)-2-Hydroxysuccinic acid ; (+/-)-Hydroxybutanedioic acid ; (+/-)-Hydroxysuccinic acid ; Dl-2-hydroxybutanedioic acid ; Dl-hyroxybutanedioic acid ; Dl-hydroxysuccinic acid ; Dl-hydroxysucoinic acid ; Dl(+/-)-malic acid               

Organism	Test Type	Route	Reported Dose (Normalized Dose)	Effect	Source
mouse	LD50	intraperitoneal	50mg/kg (50mg/kg)		"Patty's Industrial Hygiene and Toxicology," 3rd rev. ed., Clayton, G.D., and F.E. Clayton, eds., New York, John Wiley & Sons, Inc., 1978-82. Vol. 3 originally pub. in 1979; pub. as 2n rev. ed. in 1985.Vol. 2C, Pg. 4937, 1982.
mouse	LD50	oral	1600mg/kg (1600mg/kg)		Kodak Company Reports. Vol. #82-0458,
rat	LD50	intraperitoneal	100mg/kg (100mg/kg)		"Patty's Industrial Hygiene and Toxicology," 3rd rev. ed., Clayton, G.D., and F.E. Clayton, eds., New York, John Wiley & Sons, Inc., 1978-82. Vol. 3 originally pub. in 1979; pub. as 2n rev. ed. in 1985.Vol. 2C, Pg. 4937, 1982.

LD50/LC50: RTECS:
CAS# 6915-15-7: Draize test, rabbit, eye: 750 ug/24H Severe;
Draize test, rabbit, skin: 20 mg/24H Moderate;
Oral, mouse: LD50 = 1600 mg/kg;
Carcinogenicity: DL-Malic acid - Not listed as a carcinogen by ACGIH, IARC, NTP, or CA Prop 65.
Other: The toxicological properties have not been fully investigated. See actual entry in RTECS for complete information. 

Hazard Codes: Xn
Risk Statements: 22-37/38-41-42/43-34 
R22: Harmful if swallowed
R37/38: Irritating to respiratory system and skin
R41: Risk of serious damage to the eyes
R42/43: May cause sensitization by inhalation and skin contact
R34: Causes burns
Safety Statements: 26-39 
S26: In case of contact with eyes, rinse immediately with plenty of water and seek medical advice
S39: Wear eye / face protection
WGK Germany: 1
RTECS: ON7175000

Product Categories: MalicAcidSeries
Personal Protection:Eyes: Wear appropriate protective eyeglasses or chemical safety goggles as described by OSHA's eye and face protection regulations in 29 CFR 1910.133 or European Standard EN166. Skin: Wear appropriate protective gloves to prevent skin exposure. Clothing: Wear appropriate protective clothing to prevent skin exposure.
Fire Fighting:Wear a self-contained breathing apparatus in pressure-demand, MSHA/NIOSH (approved or equivalent), and full protective gear. During a fire, irritating and highly toxic gases may be generated by thermal decomposition or combustion. Extinguishing media: Use agent most appropriate to extinguish fire. In case of fire use water spray, dry chemical, carbon dioxide, or appropriate foam.