Search results
Results from the WOW.Com Content Network
Manganese(II) nitrate is prepared from manganese dioxide and nitrogen dioxide: [1]. MnO 2 + 2 NO 2 + 4 H 2 O → Mn(H 2 O) 4 (NO 3) 2. In this redox reaction, two moles of the reductant NO 2 (gas) donate each one electron to MnO 2 (black solid), the oxidant, which is reduced from its oxidation state (IV) to its lower state (II).
MnO 2 + H 2 → MnO + H 2 O MnO 2 + CO → MnO + CO 2. Upon heating to 450 °C, manganese(II) nitrate gives a mixture of oxides, denoted MnO 2−x, which can be reduced to the monoxide with hydrogen at ≥750 °C. [6] MnO is particularly stable and resists further reduction. [7] MnO can also be prepared by heating the carbonate: [8] MnCO 3 → ...
The most important is Mn 3 N 2, which catalyzes nitrogen fixation and is a high-temperature antiferromagnet. The others are Mn 6 N 5–6, Mn 4 N, [1] [2] and Mn 2 N. [3] The compounds generally form as surface layer during combustion of manganese metal in nitrogen or ammonia gas, and homogenous samples can be difficult to obtain.
Nitrogen dioxide is a reddish-brown gas with a pungent, acrid odor above 21.2 °C (70.2 °F; 294.3 K) and becomes a yellowish-brown liquid below 21.2 °C (70.2 °F; 294.3 K). It forms an equilibrium with its dimer , dinitrogen tetroxide ( N 2 O 4 ), and converts almost entirely to N 2 O 4 below −11.2 °C (11.8 °F; 261.9 K).
Manganese has no satisfactory substitute in these applications in metallurgy. [53] Steelmaking, [74] including its ironmaking component, has accounted for most manganese demand, presently in the range of 85% to 90% of the total demand. [61] Manganese is a key component of low-cost stainless steel.
Biological productivity (photosynthesis) in marine ecosystems is often limited by the bioavailability of nitrogen. [6]The amount of bioavailable nitrogen (nitrate (NO 3 −), nitrite (NO 2 −), and ammonium (NH 4 +)) depends on the inputs from nitrogen fixation and losses from denitrification and anammox as dinitrogen gas (N 2), a compound only accessible to nitrogen-fixing bacteria.
Nitrous oxide (dinitrogen oxide or dinitrogen monoxide), commonly known as laughing gas, nitrous, or factitious air, among others, [4] is a chemical compound, an oxide of nitrogen with the formula N 2 O. At room temperature, it is a colourless non-flammable gas, and has a slightly sweet scent and taste. [4]
2 MnO 2 + 4 KOH + O 2 → 2 K 2 MnO 4 + 2 H 2 O. The transformation gives a green-colored melt. Alternatively, instead of using air, potassium nitrate can be used as the oxidizer: 2 KOH + KNO 3 + MnO 2 → K 2 MnO 4 + H 2 O + KNO 2. One can test an unknown substance for the presence of manganese by heating the sample in strong KOH in air.