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Crystal structure of α-PbO 2 Crystal structure of β-PbO 2. Lead dioxide has two major polymorphs, alpha and beta, which occur naturally as rare minerals scrutinyite and plattnerite, respectively. Whereas the beta form had been identified in 1845, [3] α-PbO 2 was first identified in 1946 and found as a naturally occurring mineral 1988. [4]
Scrutinyite / ˈ s k r uː t ɪ n i. aɪ t / is a rare oxide mineral and is the alpha crystalline form of lead dioxide (α-PbO 2), plattnerite being the other, beta form. The mineral was first reported in 1988 and its name reflects the scrutiny and efforts required to identify it from a very limited amount of available sample material.
Bone marrow is a semi-solid tissue found within the spongy (also known as cancellous) portions of bones. [2] In birds and mammals, bone marrow is the primary site of new blood cell production (or haematopoiesis ). [ 3 ]
The bone mass in the skeleton makes up about 14% of the total body weight (ca. 10–11 kg for an average person) and reaches maximum mass between the ages of 25 and 30. [2] The human skeleton can be divided into the axial skeleton and the appendicular skeleton.
In the hollow within bones are many other cell types of the bone marrow. Components that are essential for osteoblast bone formation include mesenchymal stem cells (osteoblast precursor) and blood vessels that supply oxygen and nutrients for bone formation. Bone is a highly vascular tissue, and active formation of blood vessel cells, also from ...
3 Pb 2 CO 3 (OH) 2 + O 2 → 2 Pb 3 O 4 + 3 CO 2 + 3 H 2 O. In solution, lead(II,IV) oxide can be prepared by reaction of potassium plumbate with lead(II) acetate, yielding yellow insoluble lead(II,IV) oxide monohydrate Pb 3 O 4 ·H 2 O, which can be turned into the anhydrous form by gentle heating: K 2 PbO 3 + 2 Pb(OCOCH 3) 2 + H 2 O → Pb 3 ...
2 Pb(NO 3) 2 → 2 PbO + 4 NO 2 + O 2 PbCO 3 → PbO + CO 2. PbO is produced on a large scale as an intermediate product in refining raw lead ores into metallic lead. The usual lead ore is galena (lead(II) sulfide). At a temperature of around 1,000 °C (1,800 °F) in air, the sulfide converted to the oxide: [4] 2 PbS + 2 O 2 → 2 PbO + 2 SO 2
An osteocyte, an oblate shaped type of bone cell with dendritic processes, is the most commonly found cell in mature bone. It can live as long as the organism itself. [1] The adult human body has about 42 billion of them. [2] Osteocytes do not divide and have an average half life of 25 years.