Empirical Formula: C₈H₁₀K₂O₁₅Sb₂
Molecular Weight: 667.8726 g/mol
Melting point: ≥300 °C(lit.)
Water solubility: 8.3 g/100 mL
Appearance: Colourless crystals
Structure of Potassium antimonyl tartrate sesquihydrate (CAS NO.28300-74-5):
                          
Product Category of Potassium antimonyl tartrate sesquihydrate (CAS NO.28300-74-5): Industrial/Fine Chemicals;Organometallics

 Potassium antimonyl tartrate sesquihydrate (CAS NO.28300-74-5) can be used for anti-blood-sucking insects drugs added to animal feed.

The product can be derived from tartaric acid by via antimonide. Take the mixture of four copies of Antimony trioxide , and 5 copies of Potassium hydrogen tartrate into 40 copies of hot water. While stirring while heating, so that the most dissolved and still hot filtration, and then cooling and crystallization. Filtration and then refined for re-crystallization.

 Potassium antimonyl tartrate sesquihydrate (CAS NO.28300-74-5) hasn't been listed as a carcinogen by NTP, IARC, ACGIH, or CA Prop 65. And the toxicological properties have not been fully investigated. You can see actual entry in RTECS for complete information.

Antimony and its compounds are on the Community Right-To-Know List.

Human poison by intravenous route, producing liver and kidney changes, somnolence, dyspnea, and pupillary dilation. Poison by ingestion, subcutaneous, intravenous, intramuscular, and intraperitoneal routes. Large doses cause severe liver damage. Human mutation data reported. Used medicinally, the therapeutic dose is close to the toxic dose. Upon decomposition it emits toxic fumes of K₂O and Sb.
Hazard Codes: Xn,N
Risk Statements: 20/22-51/53 
R20/22:Harmful by inhalation and if swallowed. 
R51/53:Toxic to aquatic organisms, may cause long-term adverse effects in the aquatic environment.
Safety Statements: 61 
S61:Avoid release to the environment. Refer to special instructions / safety data sheets.

OSHA PEL: TWA 0.5 mg(Sb)/m³
ACGIH TLV: TWA 0.5 mg(Sb)/m³
NIOSH REL: (Antimony) TWA 0.5 mg(Sb)/m³
DOT Classification:  6.1; Label: KEEP AWAY FROM FOOD

 Potassium antimonyl tartrate sesquihydrate , its cas register number is 28300-74-5. It also can be called Antimony potassium tartrate trihydrate ; and Antimonate(2-), bis(mu-(2,3-dihydroxybutanedioato(4-)-O1,O2:O3,O4))di-, dipotassium, trihydrate, stereoisomer . It is hazardous, so the first aid measures and others should be known. Such as: When on the skin: first, should flush skin with plenty of water immediately for at least 15 minutes while removing contaminated clothing. Secondly, get medical aid. Or in the eyes: Flush eyes with plenty of water for at least 15 minutes, occasionally lifting the upper and lower eyelids. Then get medical aid soon. While, it's inhaled: Remove from exposure and move to fresh air immediately. Give artificial respiration while not breathing. When breathing is difficult, give oxygen. And as soon as to get medical aid. Then you have the ingesting of the product: Get medical aid if irritation develops or persists. 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
In addition, Potassium antimonyl tartrate sesquihydrate (CAS NO.28300-74-5) could be stable under normal temperatures and pressures. It is not compatible with strong oxidizing agents, acids, bases, carbonates, and you must not take it with incompatible materials. And also prevent it to broken down into hazardous decomposition products: carbon monoxide, carbon dioxide, antimony/antimony oxides, oxides of potassium.