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The elements in group 13 are also capable of forming stable compounds with the halogens, usually with the formula MX 3 (where M is a boron-group element and X is a halogen.) [14] Fluorine, the first halogen, is able to form stable compounds with every element that has been tested (except neon and helium), [15] and the boron group is no exception.
Boron is necessary for plant growth, but an excess of boron is toxic to plants, and occurs particularly in acidic soil. [192] [193] It presents as a yellowing from the tip inwards of the oldest leaves and black spots in barley leaves, but it can be confused with other stresses such as magnesium deficiency in other plants. [194]
Selenium, which is an essential element for animals and prokaryotes and is a beneficial element for many plants, is the least-common of all the elements essential to life. [3] [63] Selenium acts as the catalytic center of several antioxidant enzymes, such as glutathione peroxidase, [11] and plays a wide variety of other biological roles.
Plant nutrition is the study of the chemical elements and compounds necessary for plant growth and reproduction, plant metabolism and their external supply. In its absence the plant is unable to complete a normal life cycle, or that the element is part of some essential plant constituent or metabolite .
Levels as low as 0.8 ppm can cause these symptoms to appear in plants particularly boron-sensitive. Most plants, even those tolerant of boron in the soil, will show symptoms of boron toxicity when boron levels are higher than 1.8 ppm. [18] In animals, boron is an ultratrace element; in human diets, daily intake ranges from 2.1 to 4.3 mg boron ...
Excess boron is toxic to plants so care must be taken to ensure correct application rate and even coverage. [7] While boron may be sprayed on leaves, excess will cause plant damage. Application of boron may not correct boron deficiency in alkaline soils because even with the addition of boron, it may remain unavailable for plant absorption.
A borate is any of a range of boron oxyanions, anions containing boron and oxygen, such as orthoborate BO 3− 3, metaborate BO − 2, or tetraborate B 4 O 2− 7; or any salt of such anions, such as sodium metaborate, Na + [BO 2] − and borax (Na +) 2 [B 4 O 7] 2−. The name also refers to esters of such anions, such as trimethyl borate B ...
Allotropes of boron (3 P) B. Blue diamonds (12 P) Boron minerals (2 C, 1 P) C. ... Boron deficiency (plant disorder) Boron fiber; Boron on Mars; Boron steel ...