Cucumbers are mostly water, with only a small amount of carbohydrates, protein, and fat. Here's a breakdown of the chemical composition:

* Water: 95.7%

* Carbohydrates: 3.6%

* Sugars: 1.7%

* Fiber: 1.9%

* Protein: 0.7%

* Fat: 0.2%

In addition to these macronutrients, cucumbers contain various micronutrients, including:

* Vitamins: Vitamin K, vitamin C, vitamin B1 (Thiamine), vitamin B2 (Riboflavin), vitamin B5 (Pantothenic acid), vitamin B6, folate, vitamin E, and vitamin A.

* Minerals: Potassium, magnesium, manganese, phosphorus, calcium, copper, and sodium.

Other components include:

* Phytochemicals: Cucumbers contain various phytochemicals, including flavonoids, lignans, and cucurbitacins, which may contribute to their potential health benefits.

* Enzymes: Cucumbers contain enzymes such as superoxide dismutase (SOD), which may act as antioxidants.

Note: The specific chemical composition may vary slightly depending on the variety of cucumber and growing conditions.